Straw bale architecture in Japan / 日本のストローベイル建築 / Research Book by eberhard tom

STRAW BALE ARCHITECTURE IN JAPAN

日本のストローベイル建築

Ta k e s h i J i n n o u c h i / K o j i I t o n a g a / N a o k o B a b a / ShokoandHiroaki Y o s h i m o t o / KyleHolzhueter/ G o i c h i O i w a andhissonReiOiwa/ HidetoOoshima/ T a r o I g a r a s h i / MirzadelyaDevanastya/ K e i r a M a m o r u / D i r k E b e r h a r d / BastienLimouzin/

I would like to express my deep gratitude to :

Those who agreed to give me these interviews, those who built these buildings in straw bale, those who have been promoting ecological materials, those who act to improve the ways of living in Japan.

And of course, I also address a great gratitude to those who helped me in the development of this research :

At first the «Ecole nationale supérieure d’architecture de Montpellier» and «Tohoku University» who give me the opportunity to spend a research year in Japan. Then, Igarashi sensei and his laboratory. And finally my Japanese roommates and students of Montpellier who accompanied me from France.

Table of contents 4

Table of contents Purpose Postulate Approach

6 8 10

Introduction

I/ Straw in Japan

15 19

A/ Traditional use of Straw B/ A new material : Straw bale

II/ Straw bale construction in Japan

23 27

A/ Building technique B/ Performance and living aspects

III/ Current state of Straw bale in Japan

31 47

A/ 7 People B/ 7 Buildings

IV/ Future of Straw bale in Japan

63 67

A/Japanese society B/ Evolution of Straw bale

Conclusion

Resources Appendix

72 74

why ? Purpose :

Arriving in Japan, I was first confronted with Tokyo and urbanity. I grew up in a small village of 200 inhabitants located in the mountains, close to Spain, in the French PyrĂŠnĂŠes. Thereafter I studied architecture in Montpellier, a student city of 200,000 inhabitants. So I did not really face the city, the urban megacities, as it can be seen in Japan. Then I went to Sendai. Despite its 1 million inhabitants, I discovered a peaceful city, very green and bordered by mountains. I came to Japan with the ambition to visit the famous contemporary architectures of this country, now popular all over the world, and encouraged by great architects such as Kengo Kuma, Sou Fujimoto, Junya Ishigami, Toyo Ito, Shigeru Ban or Sanaa agency to name only the most known. But also to discover traditional Japanese architecture, which has invaded my imagination since childhood, with the films of Akira Kurosawa and my growing interest in natural materials. It was with this ambition that I wandered around the Japanese countryside surrounding Sendai. There, I discovered beautiful wooden temples, old abandoned buildings made in wood and clay, and others, partly covered with steel sheets or wooden planks. Materials such as wood, clay or straw, are therefore still very present in Japan, despite being damaged or hidden. Seeing this I wanted to focus my research in architecture around the Japanese ecological construction and its use of natural materials. By searching a little, I quickly realized that this represented a very wide field of Japanese architecture and a far too ambitious project for a young student who did not speak Japanese correctly. Faced with this I had to focus on a field of study that I already knew a little, and that could easily be studied using English. Having already done a research on bio sourced and geo sourced materials during my third year of architecture school, having subsequently carried out many internships in building sites using straw bales, I came to question me about the state of straw bale construction in Japan. After some research on internet, I realized that in Japan straw bale construction was mostly practiced by self builders and often under the training and expertise of a handful of artisans. There were barely four architectural straw bale offices, all helped by a straw bale builder of US nationality. So I saw an opportunity to contact this handful of straw bale professionals in Japan, maybe to interview them in order to produce a report on straw bale construction in Japan.

what ? Postulate :

In France, straw bale construction has existed for many years, as it can be seen with the building : ÂŤLa maison FeuilletteÂť, located in Montargis and designed in 1920 by engineer Ă&#x2030;mile Feuillette. This house was built with a wooden frame and a straw bale filling for insulation. This visionary architecture for this post-war era, has not subsequently enjoyed much popularity, and reappeared in France and Europe only in the 80s. Today, with the new thermal regulations and the rise of the climate emergency, the straw bale is becoming more and more popular in France. Being a material with many thermal qualities, acoustic qualities or even for the quality of the air, but also being a waste of agriculture and therefore an inexpensive material, the straw bale seems to be one of the main materials of the future in France. But what about Japan? It seems that in Japan, the current situation is close to the situation in France in the early 2000s, with the first buildings designed by architects and engineers. We begin to have the first analyzes and scientific measurements of this material, with its relation to humidity, its thermal measurements, .... After being an alternative material, used only by auto builders looking for an original and easily buildable architecture, today more and more people will be interested in this material as a healthy and functional material. If we compare this to France, theoretically the straw should know more and more popularity and scientific analyzes will be more numerous. After having correctly learned about this material, having a detailed report, the next step will therefore potentially be to train more and more professional builders. After the scientific and engineering expertise, it will be the skilled labor that will be developed. Then after these steps, straw bales can be used without problems and houses can be built for less expensive, throughout Japan. Nevertheless, France and Japan are very different countries, agriculture, history, culture and government policy are not the same. But then, if we are interested in detail, what is really the state of straw bale construction in Japan, how does society perceive it, how will it develop in the future? With all these questions I will be able to search around a general issue: What is the current state of straw bale construction in Japan?

how ? Approach :

In order to answer these questions, I will contact the various actors of construction in straw bale in Japan. I will first try to learn a little more, then to prepare more appropriate questions and interview these actors, in their homes, their offices or their cities. By going to their homes, in their areas, I will also be able to visit straw bale buildings in Japan. I will be able to photograph, to see, sometimes to enter inside these buildings, to interrogate the users, know their defects and their qualities. In order to have a good analysis of the current state of straw bale construction in Japan, I will interview different professions around straw bale: architects, builders, inhabitants, eco-builders, teachers, researchers, people building with other materials, or people not directly concerned by straw bale buildings. After contacting these actors, I will be able to organize appointments, and to plan a schedule. My research will therefore be based on the analysis of 7 actors in straw construction: two architects-builders, an architect, a self-builder, a researcher and builder, a teacher, and a member of an environmental association. In order to interview these actors, I will have to go to several cities throughout the months of January, February and March 2019, among these places we will find: Asahikawa, Fujisawa, Totsuka, Toyama, Otsu, Kumenan and Motosu. During this trip I would also have the opportunity to see many buildings in straw bales, whether houses, cafes, religious buildings or other. In total I visited 13 buildings, including 7 who will have the right to a more precise analysis. Thanks to the testimonies and the photos that I have collected, I can develop my research around 3 media: The Booklet, whose function is to show, through photographs, an overview of the panel of buildings built in straw bales in Japan. This booklet will be accessible to everyone, Japanese and English speakers, because using the universal language of photography. The Documentary Video, which presents, by means of photographs, videos and audio testimonials, several visions of straw bale in Japan. It will provide a full report on straw bale construction in Japan, explained by it different actors, with their words. It will also testify to a trip, told through photographs and videos. The research trip I made will be summarized to the audience in around ten minutes. The main Book dealing with complete research, analyzing the straw bale construction in Japan and containing the majority of the photographs, and transcribing all the interviews. This is the main Book.

Introduction : By observing the heritage we note that plant fibers are present in the oldest human constructions. They are found in particular with thatched roofs but also as exterior cladding or combined with clay as a plaster (cob). Its use becomes innovative as insulation. Loosely packed straw was already used to insulate attics or old buildings, but it is as a residue of agriculture that it now has a huge revival thanks to its excellent properties. The construction in straw bales is based on the use of raw materials and therefore does not need to go through a factory like other conventional products. Indeed it relies on a renewable resource (every year), and because of its position as a by-product of cereal agriculture it does not compete with food production. It does not require additional fields because it mobilizes a small part of the production. In Japan, it is rice straw (and then wheat) which is mainly used. But we can find constructions in all other cereals produced in regional agriculture. Then its availability as building materials is linked to the presence of an agricultural baler, allowing it to be set up as straw bale. The construction of straw bales started in the Sand Hills region of Nebraska in the late 19th century, when the first agricultural presses appeared (balers). It was practiced by the peasant-builders with small bales. The straw bale walls was stacked up and some kind of header (usually wood) is placed on top of the straw bales, then the roof is put on top of that header. This technique is still rare in Japan because of standards and regulations (especially for earthquake) but it remains the most used straw technique in the United States and is growing in some European countries such as England or Switzerland. The most common technique in Europe and Japan is the straw bale as insulation and plaster base in houses with wooden structure. The dimensions of standard straw bales are 37 cm high and 47 cm wide, and the length can vary from 80 to 120 cm. The straw bale construction has been heavily exported outside the United States in the 90â&#x20AC;&#x2122;s. It has become particularly popular for its low-tech qualities. Indeed, it requires very few tools or skills. Often the construction is done through workshops, promoting the sharing of knowledge and community work. This material have social qualities but also respects the environment : its production, implementation and deconstruction does not produce waste. Today, straw bale is experiencing a revival in the world due to its numerous ecological advantages. Straw bales are low in embodied energy. Straw bale walls function as a carbon sink, sequestering carbon during the life of the building. Straw bale walls provide sound insulation, seismic stability, and low fire risk. Straw bale walls are also highly insulative, reducing energy use and CO2 emissions due to heating.

I/ Straw in Japan

A/ Traditional use of Straw “ Traditionally, straw was very useful and important in Japan, they made everything with rice straw” ( Jinnouchi) Despite its long history in Japan (more than 2000 years), rice was, for a long time, a food for warriors and nobility. It starts to be consumed by the majority of the population only from the seventeenth century and became the staple food in the early twentieth century. Rice paddies have shaped Japanese rural landscapes and their preservation remains a priority for localities and the government. Rice is planted in the spring and harvested in September and October. In the past, peasants cultivated rice to pay the warriors’ tax, and ate millet and barley. From the time of Edo (1603-1868), rice cultivation took off and the harvests became more abundant, the peasants and common people could add a little rice to their meals. But after 2000 years of rice production, as food or as currency, this resource has become very useful and used by the Japanese. When the rice is separated from the stalks of straw, we end up with a huge amount of straw .It’s the same for other cereals, such as barley or millet, which was the basic Japanese food in old times. Braided rice straw in the form of rope is used in the decoration of shrines and the manufacture of ornaments and ritual accessories. But not only, rice straw became a popular resource, and strawbased handicrafts reverted to the elements of everyday life. Straw could be used to make rain jackets, or once woven into sandals, boots, bags, ropes and many other items of everyday life.

“ Using the straw is an ancient Japanese wisdom. There is some world heritage town, using straw as materials, for the roof.” (Baba) Straw was also traditionally used as materials in architecture. We can still see, in many world heritage sites throughout Japan, straw used as a roof covering. Thatching was used commonly for the roofs of traditional houses, temples and shrines. Today there are approximately 100,000 thatched buildings in Japan, which makes the country one of the bigger, talking about numbers of thatch. There are around 300 thatchers working to maintain and renew this cultural heritage. When we talk about thatched roofs in Japan, we think of Shirakawago, in Gifu Prefecture, or other world heritage site. However, thatch roofs were common throughout central Japan. It is not uncommon to see houses with strange roofs in the Japanese countryside, they are in fact thatched roofs zinced or covered over. Indeed the roof must be renewed completely every 50 years, but with the lack of money to maintain this technique, many choose to cover this roof of zinc, most often, or tiles. The thatched roofs - kaya in Japanese - are really good materials (for insulation also) but need a special pose to ensure a tightness. The most used material is “Susuki”, Miscanthus sinensis. But probably for a large portion of the lost wealthy farmers in Japan, straw was the common roofing material.

“ In Japan straw was used as traditional materials for walls, cutting straw and mix it with clay.” (Itonaga) Japan is a country where earthen construction is omnipresent. Even in large cities it is not uncommon to see an old building with plasters damaged by time, thus revealing the different layers of earth applied. The most common technique on the archipelago is plastering, used on a secondary bamboo structure. Conventional and traditional architecture in Japan consists of a wood structure and then without insulation, a bamboo mesh between the wood elements, on which we will put a plaster composed of earth and straw. Then other finer plasters will follow. There are many different plasters with different proportions of clay, sands and pebbles, straw, or other elements. But basically the straw is composted, fermented and then mixed with clay. This tradition of earthen plaster came from two aspects of Japanese life, the tea ceremony and the fear of fire. Between the 9th and 13th centuries, Buddhist monks brought tea from China to Japan and in the 16th century, Zen practitioner Sen no Rikyu, established the tea ceremony. The tea ceremony generally takes place in tea house, following the Japanese aesthetic of «wabi-sabi». The walls of the tea houses are plastered with earth. It was ask to the craftsmen to create unpretentious, but refined earthen plastered walls. In this way, tea and the Japanese aesthetic led to the high development of fine earthen plastering in Japan. In Japan, fire was also something to be feared. Since most traditional Japanese buildings are made with a wooden structure, the danger of fire was ever present. In order to protect buildings from fire a thick earthen plaster was made. The massive earthen walls of these buildings protect valuables from fire and food stuffs from rodents and temperature extremes. However, Japan also experiences high precipitation. In order to protect the earthen walls from weathering, storehouses were often finished with a thin coat of Japanese lime plaster . Through tea and fire, we see two streams of natural plastering in Japan, fine finishes to be appreciated and functional massive earthen walls for protection. “ It is a valuable resource that is gone out of use.” (Holzhueter) But today apart from its minimal use in earthen plaster and some roofing craftsmen in thatched roof, the craft of straw disappears. Traditionally, Japanese architecture was based on natural materials. All the elements of the houses and temples were using wood, natural fibers and clay. The architecture was based on the concept of «come back to the earth». But today these techniques and materials are less and less used and are replaced by a large use of industrial and chemical materials, such as concrete, plastic, or glass fiber insulation.

I/ Straw in Japan

B/ A new material : Straw bale â&#x20AC;&#x153; In Japan, some farmers will do straw bales probably just to deal with the straw.â&#x20AC;? (Holzhueter) As we have seen, straw, usually used in the objects of everyday life, becomes a waste. Often when the rice is harvested, the straw is cut and left in the fields. But rice straw is quite resistant to decomposition and therefore does not compost quickly. This is why it is viewed in a negative way, as a nuisance waste, and most often the farmers prefer to burn it to clean the field. This is where the straw bale makes its intervention. Indeed balers was introduced in the second half of the twentieth century in Japan by the United States. They are used to manage this waste, to make it easier to transport and store the straw. We find originally square straw bales but nowadays it seems that it is the big round straw bales that are the most used. Because they are larger but also because they can be wrapped in a vinyl film, protecting it from the rain. If in Europe, we still find a lot of square shaped straw bales, it is because they are used for horses and livestock. But Japan is not a breeding-based culture. Then the straw are sometimes put into bales, for no real purpose, or it can also be used in the fermentation process of Natto (fermented soybeans). There is a lot of straw in Japan but the main problem is that rice harvesting is held in Automne, during the rainy season. Then this material is hard to keep and dry. Japan donâ&#x20AC;&#x2122;t have a strong system to stock this straw and thoses straw bales. Some of them let straw dry in plastic greenhouses but in Japan, having a shed to store the bale is rare. Because of this lack of system straw bale are rare and expensive.

â&#x20AC;&#x153; In Japan, if you want to build a house with straw bales, agricultural cooperation will be necessary.â&#x20AC;? (Ooshima) In Japan, if you want to build a house by yourself or built for someone, you need to find a farmer that want to make straw bale, it works on personal basis. The personal links will be important. You will need to have a good relationship with a rice or cereales farmers, or with a cow or horse breeder who will have the ability to find or make bales. It is often necessary to negotiate with the farmer. For example, if you want to use the straw to make bales, you will have to cut the rice straw in longer sections, which can annoy the farmer. If you can not buy the straw bales, you can also manage to borrow a baler. Indeed, in the past, Japan has not found much utility in the balers and most have been left out and abandoned. Many are therefore unusable today, rusty and damaged by the humid and rainy climate of Japan. But there are still some, scattered in the Japanese campaigns. You can easily borrow these to make bales yourself.

â&#x20AC;&#x153; It is actually cheaper to import straw bale, that it is to buy domestic straw bales.â&#x20AC;? (Holzhueter) Because of all this, the straw bale can sometimes be expensive. Because there is no system around it, you have to create your own, and that goes through conflicts, work and costs. In Japan the straw bale can cost between 500 yen and 1000 yen. While in other countries the straw bale is experiencing a great rise because of its very low cost (in France it can be found between 300 and 500 yen for comparison). Nevertheless, this purchase provides additional income for the farmer by buying a resource, which for him was only a waste. But sometimes because of its very high cost, it is often cheaper to import the straw bale from areas where the system is already developed. For the construction of slow coffee and other straw bale buildings in the Tokyo area, the straw from Toyama was used. But these trips also involve pollution and additional cost. Hence the importance of creating a system gradually, to be able to provide straw bale all over Japan. Bales of rice straw are the most common type of bale, while bales of wheat straw, dried meadow grasses, susuki (Miscanthus sinensis), and bamboo grass (Bambusoideae luerss) are also available in some areas of Japan. Rice straw is the most available, logically because it is the most cultivated cereal in Japan, it is a good material, really resistant to moisture. But because the rice straw is difficult to dry, the harvest being done during the rainy season, the wheat straw is much used in Japan. It is harvested earlier in the summer and allows for optimal drying conditions.

II/ Straw bale Construction in Japan

A/ Building technique “ Straw bale constructions are mainly made by self builder or during workshops.” ( Jinnouchi) In Japan, there are only a handful of professionals builders specializing in the straw bale, who work on straw bales as an income. We find Kyle Holzhueter, based in the prefecture of Yokohama, who advise and work with many self-builders and intervenes in the workshops. Kyle Holzhueter worked a lot on the straw building designed by Goichi Oiwa and the “Slow design” architecture office. Otherwise there are two architectural firms specialized in drawing and construction of straw bale buildings, one in Toyama: “Sakichi Kenchiku”, and one based around Nagoya: “Straw bale project”. Apart them, we will mainly find self-builders. These actors of straw bale construction in Japan are sometimes architect and builder straw, some are also carpenter or plasterer. So there are not many professional builders in Japan, but these few builders are in contact and are working to help and teach the Japanese to build in straw bale. Some works on professional training, others act during workshops and advice many Japanese wishing to self-build their houses in straw bale. There is no regular Japanese construction system for straw bale. Almost all straw bale buildings in Japan were raised in a workshop type format. Mainly because it is not a very difficult skill to learn. Straw bale buildings are easy to build, and it is pleasant to getting hands dirty and working on materials like straw or earth coatings. Even women and children can have a lot of fun when they work on these workshops. Still, these workshops are often under the instruction of someone with experience. Almost all of these experienced builders took workshop with the Straw bale building association. It is an association made 13 years ago, in Nasu, near Fukushima. This association don’t exist anymore, but it was found by Umagami san, who was one of the first people to bring straw bale in Japan. There is also a lot of self taught straw bale builders. Most of the time you can find problems of insulation, or some insects and rodent. But it can also be very dangerous, especially in the case of load bearing buildings, if it is poorly built, because the building can be strongly affected by the rain.

â&#x20AC;&#x153; Right now, I think the majority of straw bale buildings in Japan, incorporate straw bales with the conventional Japanese timber frameâ&#x20AC;? (Holzhueter) In Japan, we cannot build straw bale as a structural system. Under Japan construction law, it needs a wood structure. We can still find some buildings in load-bearing, but they are rather rare because it makes the permit process more difficult. Then, most of the straw bale buildings are combined with a wood structure, a conventional one. With this structure, the problems of earthquakes are automatically avoided because managed by the wood frame, moreover the straw bale being flexible, it behaves very well and damped the vibrations. But the problem with the conventional wooden structure are the big and thick diagonal bracing inside the wall. It makes it impossible to put the bale between the posts. Then the bale needs to be entirely on the outside or entirely on the inside. And in that case, you are left with this very large gap between the post that need to be filled with something. Sometimes this gap is filled with stuffed straw, it is an easy option. For more efficiency, you can also fill that gap with light rice husk using lime or clay, or light straw clay. It is an additional step that need to be done. There are other obligations regarding the use of straw bale in buildings. The japanese climate is very humid, with a lot of rainy days. And humidity is the biggest ennemie of straw bale. To avoid the contact between water and the straw bale, most of the time, clay plaster is used. Indeed clay plaster are used for centuries in Japan, and if the rain touch the plaster there is no problem. But the problem is if clay accumulate too much water, in winter, it risk to freeze and to break the plaster. This problem can be solved with a longer roof. Straw bale buildings need to have a long roof to avoid too much contact with water. It is not easy to extend the roof because then it becomes heavier. To support it, you can add poles to the outside, but then you also need a base for the poles, which can be expensive. The straw bales also involves larger walls and therefore larger foundations. In addition, the junction between the straw bale and the foundation must be correctly put in place with a capillary break in order to prevent the water from going up in the straw wall. Another specificity that can be found in straw bale building in Japan is that most buildings are made during workshops. This non-professional construction process involves working in safety and thus prevents complex elements. So we can easily observe that many straw bale walls are only 2 or 3 meters high. Then we end up without insulation, or with another insulation, to the roof. And the roof too will not be insulated. Therefore, unlike other countries, the straw bale is not used so much for its insulation qualities.

“ Most of the cost will be labour cost. So I don’t think it is cheaper.” (Ooshima) The buildings in straw bale are not too complex to achieve and especially they can be realized in a short time. Beforehand we will have to put in place the foundations and the wood frame, but later, the setting up of straw bales is done very quickly. For small buildings such as large buildings, the laying of straw bales and the first coating earth can be done between 3 and 5 days in a workshop type format. For self-built houses of course it will be longer but basically stacking straw bales and the first plaster coat can be done quickly, then it will only remain to apply a final plaster. Straw bale buildings are build in workshop also because the cost of labor is quite expensive. You can also proceed by doing participative projects where the client is involved in the construction of his house. Thus we can reduce the time of construction and therefore the cost of labor. The price of the straw bale does not really affect the total cost of the house. The cost of the wall is only 20% of the total cost. Even if the straw bale were free, it will not really change the cost of the building. The problem is that if you want to use straw bale, your foundations tend to be bigger, which implies an additional cost. If you want the same floor space, then your roof tends to be bigger. And that is why the cost increase, with the foundation and the roof.

II/ Straw bale Construction in Japan

B/ Performances and living aspects â&#x20AC;&#x153; In other straw bale houses, I sometimes had failures. â&#x20AC;&#x153; (Oiwa) Most of the time, people are satisfied with their straw bale houses. The design is attractive, air quality is good and most of the time the straw wall works well as insulation, and the house remains pleasant in winter as in summer. But often there are also problems, each problem having its reasons. The most common problem is moisture. Sometimes the plaster breaks and the water go inside the straw. If the plaster is not well made inside, there isnâ&#x20AC;&#x2122;t any problems, but outside, it is a problem. It is really important to apply well the plaster, especially on joint parts. To be sure to avoid this problem, some add a wood facade on the outside, after the plaster layer. To build a straw bale house, you have to carefully understand the climate : rain, wind, mountain,etc....

“ We feel strange, strange but comfortable. I can’t really explain it, but it is comfortable. “ ( Jinnouchi) If you identify the dangers, you discover that straw bale have many qualities. First, it is a very efficient insulation material, with a lambda (thermal conductivity) around 0,08. This allows these houses to remain comfortable in both summer and winter, in areas ranging from Okinawa to Hokkaido. Straw bale avoid spending too much energy to heat these houses, and most of them don’t need air conditioning in summer. This insulation is also due to the thickness of the wall, which is not usual in Japan. Indeed in Japanese houses, the walls are very thin. The old Japanese houses are cold in winter and hot in summer, the notions of comfort being different at this time. This change of comfort that has occurred since, also implies accepting the need to further isolate homes and to accept these thick walls. Some people see thick walls as comforting and protective. In Japan, it is not usual to insulating the house and few old houses were airtight. The interior remained sufficiently comfortable by the use of the earth as inertia. Clay plaster have the ability to store heat. While people try to seal more and more the house to isolate it and avoid bringing warm air or fresh air, the materials used in Japanese homes generate a lot of harmful substances. Therefore, ventilation is very important. But it’s a pity to let the hot air escape.That is why heat storage becomes very efficient. With its good relationship with clay plaster, straw bale house allows for a real breakthrough. As Goichi Oiwa said : “ The first reason we built in straw bale house is that it creates a good and truly healthy bioenvironment. The second is that straw bale can connect people and the community. Third, is that straw bale house connects people to nature. The fourth, is that the straw bale house connects people and people. It means the people inside the community and the people outside the community, as in the workshops. The fifth is story. Straw bale house is connected to the past, to history and creates new stories for the future at the same time.” People who find environmental and self-building quality in straw bale, now are more attracted by earthbag houses. Because earth is easy to find, the walls are thinner and the design is even more organic (with round shapes and domes). But with this material you don’t find the quality of insultaon find in straw bale and people slowly realize that straw bale is more comfortable.

“ There are many obstacles in Japan.” (Ooshima) Japan remains a country where straw bale construction can be difficult. It is a very rainy country, while water is the main enemy of the straw bale. There are many earthquakes, the government is not yet promoting the development of alternative and low-tech materials, and there is a great fear of fires in Japan. In spite of all this, the straw bale construction manages to cope with these constraints. There is almost no place in Kyushu, Honshu, Shikoku, or Hokkaido that you cannot build with straw bales. It can be used almost everywhere in Japan. Okinawa might be a little different. In fact, it is even very effective in mountain areas or colder areas of Japan. So if you correctly design the building, humidity is almost entirely a design and build issues. In the case of earthquakes, the straw bale is most often coupled with a conventional wooden structure and absorbs vibrations. It does not become troublesome but is even a good material to follow and accompany classical Japanese seismic structures. Regarding fire, the straw bale is now known to be fire resistant because of its density. What’s more, coupled with a wooden structure, it slows the combustion of the house by preventing the fire from reaching the wood. This has not yet been tested in Japan, but the straw bale construction remains safe thanks to the use of a thick coating of clay protecting it from fire. Banks, also, don’t want to accept a loan for houses in straw bale. This is because there is no guarantee on the thermal insulation of buildings as well as for lack of example and precedent. That’s why thermal performance analyzes have been done on public facilities built in straw bale. Now with the test result, it is possible to receive a loan to build a straw bale house.

III/ Current state of Straw bale in Japan

A/ 7 people : As explained in the Introduction, straw bale buildings were first built in USA in the late 19th century. But there was a revival of straw bale construction in the USA in the 70’s and 80’s with young people leaving cities for the countryside, known as the “back-to-the-land movement”. This allowed straw bale to be export abroad, in the Europe, and also in the Japan in the 90’s. The first ones to start building in straw bale were self builder, who take inspiration from the USA. It is like this that Takeshi Jinnouchi discover straw bale construction in 1995. Indeed he saw a straw bale construction in “the real good” magazine and was directly inspired as an architect. Shortly after that, in 1996, in Hokkaido, he built with other people one of the first straw bale building in Japan. Some years after, it is the university professor Koji Itonaga and Goichi Oiwa that discover straw bale in Australia, respectively in 1998 and 1999. They both meet straw bale in Australia, in small communities and permaculture centers. After this experience, Goichi Oiwa decides to study again straw bale houses in the USA, in 2000. In 2002/2003, it is Kyle Holzhueter, coming from the USA, that encounter straw bale in Australia when visiting a permaculture center. After that he decides to learn some straw bale skills in the USA and finally joined the Itonaga sensei laboratory, in Nihon university, Japan, and study straw bale with a scientific point of view. In 2003, the young architect, Hideto Ooshima saw a straw bale house on a TV program and was directly attracted. It gives him hope about the future of japanese architecture and decide to built his first houses in Japan directly after that, with the help of a builder from USA. In 2004, Hiroaki Yoshimoto discovers straw bale in a magazine and it immediately opened his eyes to new architectural possibilities, with organic forms, approaching the architecture of Gaudi. He decided to join Kassel University in Germany to learn more about straw bale with the german architect Gernot Minke. Naoko Baba discovers straw bale with «the Sloth Club» and the workshops of slow buildings, designed by Goichi Oiwa and built with the help of Kyle Holzhueter, Hideto Ooshima, Koji Itonaga and Hiroaki Yoshimoto. All those people are important in the straw bale history in Japan, some as architect, some as researcher, some as builder, some as inhabitant and some just as “japanese”. They were all interviewed from January to March 2019.

1/ Takeshi Jinnouchi

Takeshi Jinnouchi was my first interview for this research. He welcomed me in his personal house in straw bale, near Asahikawa (Hokkaido), from 23th to 28th of January. Takeshi Jinnouchi is graduated in architecture and first worked as architect in an office in Tokyo. But he fastly retired and start working on environmental issues. Returning in Hokkaido in 1992, he worked in forestry and rural living. He is one of the first japanese to build in straw bale, it was in 1996. He makes an experimental building with volunteers based on american documents. After this, he start a musician career in Tokyo and then after returning in Hokkaido, devoted his life to carpentry, forestry and ecological building. In 2006, he built his own house in straw bale and also established his forestry NGO, which explore the relationship between urban residents or childrens and forestry.

2/ Koji Itonaga

I have meet Koji Itonaga in his office, in the Nihon University, department of building science in Fujisawa. It was the 08th of February. He was the second person involved in straw bale construction in Japan that I have met. Koji Itonaga is a professor in the department of bioenvironmental and agriculture science. He works a lot about rural planning and revitalization. He have conduct a lot of research about sustainability, materials and also environmental disasters. He have a look on problems in japanese society and the solutions that can be made, for him it is now more important than all to develop local japanese wood for the construction. He was the professor of Kyle Holzhueter when he researched about hygrothermal environment of straw bale walls. In 2014 he received an award for rural planning society works. He is involved in a lot of works mainly concerning resilience design, community support, and eco-lifestyle.

3/ Naoko Baba

Naoko Baba is the secretary general of the Sloth Club. She is the third person that I met concerning straw bale in Japan. She is not an architect, not a straw bale builder, she is just surrounded by it. She participated in workshops and is working inside the café Yukkurido, a straw bale building. This is where we have meet, in the café Yukkurido and Zenryoji Monshido, in Totsuka (Kanagawa), the 9th February. The Sloth club is a NGO, set up in 1999 by Keibo Oiwa, a cultural Anthropologist. It is an association open to everyone, student, working people, from all countries. It was found to preserve the sloth, but also to imitate its behavior and “lazing like sloths”. Indeed, Japan is the third economic power and it has acquired this status in a very short time thanks to immense productivity and strong growth for only a few decades. In this country where everything must go fast, the model of slow life makes a lot of sense. The sloth club have established itself inside the slow café, in Kokubunji. But also built other slow café in Totsuka and in Hokkaido. They are all build with straw bale. Those café are organic restaurant, community centers, they also sell fair-trade products but also organise events and workshops around slow life and environmental issues.

4/ Hiroaki and Shoko Yoshimoto

Hiroaki and Shoko are both architect, working together in the office Sakichi Kenchiku, based in Toyama. I met them the 16th of February. Hiroaki is also a carpenter by trade. He works on organic architecture and on electronic wave measurement. He is affiliate to the Japanese Baubiologie study group. He also have made many research concerning the humidity and the temperature in straw bale architecture and work a bit as plasterer. He is the only one I met in Japan who received his formation and knowledge in straw bale from Europe and Germany, with Gernot Minke, famous architect and writer on earth and straw buildings. His wife, Shoko Yoshimoto is a first class architect and also work in a forest child institution.

5/ Kyle Holzhueter

Kyle Holzhueter was interviewed in his permaculture center near Tsuyama, in Okayama prefecture. It was from 04th to 09th March. He was born in the USA but now live in Japan as a builder, a researcher and educator in natural buildings and sustainable systems. He studied organic and biodynamic farming in US, permaculture in Australia and natural farming in Japan. He is also graduated from Kyoto plastering institute and work now as plasterer. In 2011, he completed a PhD in Nihon University, bioresource science Lab, from Koji Itonaga, researching on the hygrothermal environment of straw bale walls. Since that, he built many straw bale buildings in Japan, advise and teach in a lot of workshops. He also have been working on light straw clay and light rice husk. Since 2017, Kyle found Permaculture center Kamimomi, in Okayama prefecture, where he hosts workshops about natural buildings and permaculture systems.

6/ Goichi Oiwa

Goichi Oiwa was the main architect of straw bale buildings in Japan. He designed with his architecture office, «slow design», more than 20 straw bale buildings in Japan. He was also professor in the faculty of design of Seian university. After working 23 years in an architecture design office in Tokyo, in 1999, he discovered straw bale and creates his own design office, slow design. This was also due to his engagement as a member of the environmental NGO «the Sloth Club» created by his brother, the anthropologist Keibo Oiwa. Since 2001, he presides the «Slow design study group» working on living and the creation of a new ecological lifestyle. With his students, they were working on the Japanese lifestyle without being dependent of nuclear energy. They studied to reduce the use of electricity in a fashionable way and also created the «suito movement», against the existence of automatic vending machines in Japan. With his office, «Slow design», he was focusing on connections, on small and humble things. He wanted to build local with promotion of craftsmen.

7/ Hideto Ooshima

Hideto Ooshima is the representative of «Straw bale Project» architecture office. He was the last one I interviewed, in Gifu prefecture, around Nagoya, the 21th March. After graduating from University, he started working in an architectural design office. But when he realized the reality of housing in Japan, a combination of standardized and mass produced industrial products in order to improve economic efficiency, he losts his joy about design. It is when he discovered straw bale in a video from USA, in 2001, that he find hope again. After that, he started researching on straw bale house by himself, and improved it years after years. In 2004, he founded the architecture office «Straw bale Project», that now involve 7 members. The work of this office is to propose designs and to supervise architectural design around straw bale construction. They put forward the heat insulation, durability, fire resistance and seismic resistance in their buildings. They also assure the construction and the maintenance of the straw bale buildings. They mainly work in a participative way, with workshops and also work in collaboration with Koji Itonaga and his Nihon University’s design Lab.

III/ Current state of Straw bale in Japan

B/ 7 buildings : If we take a look at all the straw bale buildings I saw in Japan, we find buildings designed by architectural offices and some by self builders. In fact in Japan, the majority of straw bale buildings are made by self builders. In the panel that can be seen here, we find mainly buildings made by the office «Slow Design» and the architect Goichi Oiwa. This is due to the simple fact that the buildings designed by this office are better documented and their addresses can be easily found. Among other straw bale architecture offices in Japan, we find the office «Sakichi Kenchiku» in Toyama with architects Shoko and Hiroaki Yoshimoto (whose buildings will not be presented here but in the booklet), as well as the office «Straw bale Project» around Nagoya with the architect Hideto Ooshima. Apart from these architectural offices, we will present an experimental building on the permaculture experimentation field at Nihon University, by Koji Itonaga. We will also find the house designed but also inhabited and built by Takeshi Jinnouchi in Hokkaido. When we observe all these buildings we observe similarities due, among other things, to the fact that most of the time they are built during workshops. It will be noticed that on many buildings the wall in straw bale will not be very high. With that, except for the house in Hokkaido, it can be seen that the straw bale is more used for its aesthetics and qualities of healthy natural materials, rather than to insulate the house thermally. Often in these buildings, the main element being the wooden structure, the straw wall will come to fill the spaces between it or to protect it by creating a facade. The straw bale becomes a healthy, pleasant material, easily put in place to complete the wood structure and so, with the clay plaster, completely finish the building. Unlike other countries, such as France, where straw bale buildings are designed by builders and experts, here in Japan, the aesthetics of the straw bale building is important. Indeed, the straw bale disrupts the traditional Japanese aesthetics of thin walls and must create a new imaginary around the thickness. The wall becomes massive, with roundness, curves, it comes into relationship with the structure, hiding or bringing out. It is an architecture thought in a workshop process, in a manufacturing process, and therefore the attention to detail will be important. Because of the use of clay plaster indoors, the light clings to the walls and will diffuse a beautiful warm light. The use of clay plaster outdoors will help to harmonize with the traditional houses. Indeed we will easily notice a house in straw bale but nevertheless it does not contrast too much with the traditional Japanese architecture, and even it will render somehow homage. In Japan, the straw bale architecture is in contradiction with the traditional Japanese architecture and at the same time pays tribute to it. It reuses the natural materials used centuries ago in Japan, adapting them to the modernity of this world as well as new challenges and comforts induced by this same world.

1/ Atom House

Atom house is probably one of the first straw bale buildings, in Japan, built for experimental purpose. It was built in Nihon Universityâ&#x20AC;&#x2122;s Center for Natural Environmental Sciences in Fujisawa (Kanagawa Prefecture). Its construction starts in 2002 and was completely finished in 2006. This buildings was design by the professor Koji Itonaga and also by the architect Tono Mirai and students of Nihon Universityâ&#x20AC;&#x2122;s Architecture and Regional Ecological Design Studio. It was designed to experiment materials such as straw bale, but also clay, rammed earth, cob and some alternative techniques. It was also to experiment solar power and manage inertia using rammed earth and straw bale insulation. That is also why they have placed some sensors, six inside the straw bale wall, one inside the buildings, and one outside. With these sensor they can observe variations of humidity and temperature inside the wall. But this straw bale building was rather poorly constructed and designed and today it is slowly falling apart. Indeed, the relationship between the straw wall and the roof has not been well studied. It can be seen that the straw wall and the roof were even joined together by the earth plaster. If the roof does not sufficiently protect the straw wall and especially if there is no rupture between the two, the rainwater will infiltrate, crack the coating earth and then enter the straw wall, making it moldy. The weak points of the straw bales are mainly, the top and the bottom of the wall. In order to protect it from the water, it must have a capillary break between the foundation and the straw wall. Then the water does not rise back into the straw by capillarity. Regarding the top of the straw wall, it is much faster. If it is not sufficiently protected the water will go directly into the wall and humidify in its entirety. As is sometimes said, the most important thing against rain is the hat and the boots.

2/ Seian University of Art and Design Cafeteria

This cafeteria was built during the 2004 academic year, from April to September, to be opened to the public in October. If this project was realized in a very short time, it is because it was imagine and put in place by the professors and the students of the Seian University of Art and Design. It is in this university, near Lake Biwa, in Otsu (Shiga prefecture), that Goichi Oiwa, architect of slow design, but also professor in this university, launched the project. This project is built as a training structure for construction and enhancement of local craftsmanship. It is a simple building, composed of an apparent wooden structure, then there are windows between the wooden structure composing the external facade. Finally inside this volume, a sanitary block in straw bale is set up. It is a small volume of straw bale welcoming the kitchen and two toilets. The use of the straw bale may seem useless but the straw bale, here, will not serve as thermal insulation but as a very good sound insulation and hygrometric regulator. Straw bale, combined with the clay plaster, will very well ensure this dual function, while creating a visual break with the rest of the building, made in wood and glass.

3/ Jinnouchiâ&#x20AC;&#x2122;s House

This big house was built near Asahikawa, in the mountains of Hokkaido. It was designed by Takeshi Jinnouchi, as a straw bale architect but especially as the owners of this house. I think it is the only building I have seen in Japan that uses the straw bale from floor to ceiling to completely insulate the house. In these mountains where it is very cold in winter the insulation is very important, there the straw bale becomes very interesting. This building was built in 2006 using not rice straw or wheat straw but straw bales made from long grass. In one or two weeks, Jinnouchi san and his wife borrowed a baler and produced 850 straw bales for this house. Then the wooden structure was made conventionally with a young carpenter. The timber sections are large and there are many posts because of the large snow loads in the area. Then Jinnouchi, with some friends, placed the straw bales one by one, in a month and a half. Subsequently, the clay coating was done in 3 or 4 months by him, his wife and friends. This part took a long time because of his reduced knowledge of clay plaster at the time. Thatâ&#x20AC;&#x2122;s why, in the end, the last layer of plaster was realized during a workshop, by a young plasterer, Noda san, helped by 40 people, in just two days. This house is a testimony of a great construction done by a self builder and architect, almost made by him alone. There were many problems and a lot of work to make this house where he lives today with his wife. Today we can see many faults that mainly concern the clay plaster. It sometimes breaks or cracks due to frost and snow, bringing fresh air outside the house in winter.

4/ Shinrin no koubou

This building is a café but also an organic market, located near Kyotango in Kyoto Prefecture. It has been designated by Goichi Oiwa and slow design, at the request of an environmental company based on a sustainable forest dairy. By working to preserve the forest ecosystem while producing milk, this café will promote quality milk production combined with environmental education. This building is therefore a community center practicing new economic and production models based on sustainable and environmental management of ecosystems. It was built at the end of 2007. Here the straw bale is not used everywhere. It will be particularly present on the south west facade. The rest of the house will be in wood panels with, probably, a thin insulation. Difficult here to know the role provided by the straw bale because it is sometimes found over the entire height of the wall or sometimes only 1 meter high. It seems that it has been put in place for aesthetic purposes and not as an insulation material. Indeed it brings a beautiful aesthetic to the building with its very thick wall forms and rounded corners. But it also has some mistakes. Here it is not the roof and its edge that are questioned but the management of the holes. Indeed another important point in straw bale houses is windows and doors. It is also necessary a good protection against the rain, having a sufficient roof overhang so that the rain does not flow along the plaster. The joints will also be important because we must be careful not to seek continuity between the elements using the clay plaster, as it was done here. Although this creates a beautiful aesthetic effect, the connection will also allow the water to cling to the plaster and then get inside the wall. If on the roof, the clay plaster is cracking, it will not be too dangerous as long as it is protected by a roof overhang. It is also necessary that the clay plaster or the straw wall doesn’t touch the ground, you need to disconnect it from the ground so that the rain doesn’t goes up in the wall. Here it has been done, but not in the outdoor terrace. Since this brings an extra height, the rain will splash on the straw and clay wall when the rain hits the ground.

5/ Café Yukkurido

This buildings was built for the revitalization of the local community in Yokohama urban area, in Totsuka, and to welcome the NPO association “Café della Terra” specialized in environmental and culture activities. It was designed in the end of 2010 and beginning of 2011 by the architect Goichi Oiwa and his architecture design office “slow design“. Finally the construction started in summer 2012 as a workshop. The building is also built in response to the Tohoku earthquake and tsunami in 2011. For this, all the wood used comes from this region to financially support this territory in destruction. You can see videos of this workshop and explanation about it in the french TV program “Tracks Sloth club” (available on youtube). Although the whole building is more complex, the straw bale part is quite simple. It is a straw bale wall corresponding in plan to a round. Then there is a large stainless steel roof supported by wooden posts separated from the straw wall. The fact of having detached these two elements, the wall and the roof / structure, makes it possible to have a large roof protecting correctly the straw bale wall. In addition, the effect produced is visually very pleasant. Unfortunately straw bales are used only in front and it will be thin wooden walls on the other parts of the building. Due to its round shape, the junctions between the straw wall and the square roof is also very complex and difficult to achieve.

6/ «Straw bale Project» concept house

This building, isolated in the mountains of Gifu Prefecture, was built in the small village of Hinata. This is where the architecture office «Straw bale Project» decided to build an experimental house in straw bale. Built in 2012, it serves as a witness and exhibition building but also occasionally as a working space for this architecture office. Here the straw bale is not visible from the outside even if we feel that the wall is unusually thick. In this cold and humid region, Ooshima san, the architect, decided to don’t leave the clay plaster coat as it is, but to protect it with a wooden facade. Thanks to this protection and the overhang of the roof, we can ensure that the straw bales will be protected from moisture. In the interior, however, you can see the earth plaster and easily guess the composition of the wall. We are facing a conventional wooden structure using wood elements of an old framework. The posts here are inside the straw wall and the straw bale will be placed outside the structure. Unfortunately, even if the straw is properly used as insulation for the facade, the roof will not be insulated, but just composed of thick wooden planks (6 cm in total), before the roof tiles.

7/ Zenryoji Temple

This temple, located in the same place as the café Yukkurido, is actually attached to it. Indeed this complex consists of three volumes: the temple, the retirement home (not in straw bales), and the café. These three places communicate spiritualy with each other, respectively: with oneself, with the community and with the outside world. Here also the wood used comes from Kurihara town, Miyagi prefecture, in Tohoku. This building has undergone a renovation later in 2016, which notably gave this straw facade, inspired by traditional japanese thatched roofs. Here, therefore, apart from this thatched facade, we do not perceive the straw walls from the outside. Indeed, the clay plaster is protected by a wooden facade and will be visible only from the inside. It is when entering the temple that its architecture is revealed. Indeed the wooden structure is very delicate and thin and being disconnected from the straw bale walls, makes them stand out even more. The design is also in appearance very simple, two walls in straw bale with clay plaster on each side, a wooden structure holding a high ceiling and at the end the ornaments and the statue of the Buddha. These are illuminated by a clever play of natural light diffused along the wall. The wood of the ceiling and the walls being dark, they bring out surprisingly the straw bale walls with their plaster as well as the structure wood. Unfortunately, designed during a workshop, the straw bale walls don’t go up to the ceiling and reach about two meters, to be easily set up. In this building the straw bales come from wheat, and the whole building was designed following the principles of «back to the earth», in a will of strict use of bio and geo sourced materials, so that during its destruction or dismantling it does not cause any damage to the environment. Unfortunately regarding standards it was mandatory to use concrete foundations, but the monk has managed to use the form boards to the hidden part of the ceiling, it is a nice little victory.

IV/ Future of Straw bale in Japan

A/ Japanese society “ I feel that the general public pays attention for their living space “ (Baba) It seems that even in the mainstream, people start to think more and more about their living space. People are now looking for more healthy houses. Until now, industrial materials have developed very well in Japan. Although wood carpentry construction continues to exist and be used, materials such as concrete, glass fiber insulation or chemical paints are very prevalent in Japanese homes. These materials make indoor spaces very polluted and the air is not healthy enough. That’s why now many people are starting to have skin problems, or allergic problems. The issue of indoor air quality and quality of materials is becoming more and more popular. The Japanese want healthy, chemical-free houses. Unfortunately alternative chemicals-free materials and products remain expensive and many can not afford to buy them. Some people will also try to build their own houses or renovate old houses. Many find themselves living on the sideline of current society and government, in the countryside. In the same way, some decide to don’t live in a house and to follow the movement of Tiny House. This movement is gaining popularity in Japan, many people decide to build their own small nomadic habitat around a vehicle, in the back of a car or truck. They choose not to have a home base, but to travel, to move, to live in sobriety, with very little. Many also remain very interesting by constructions in straw bales. Although only some ultimately decide to actually build one, many inquire, visit houses in straw bale or ask for advice. In Japan, a country where energy consumption is high, many people are beginning to have an ecological conscience and try to question their lifestyle habits, their consumption of electricity and materials and try to return to a lifestyle closer to tradition and environment.

“In the current circumstances, people with an environmental conscience work on the sidelines.” (Ooshima) Unfortunately, the Japanese government is doing very little in the sense of the environment. For heating, for example, the use of kerosene is still very popular while it is now known that it releases carbon monoxide and other toxic gases. Many Japanese people also use air conditioners to cool in the summer or to heat in the winter. Unfortunately, there are few alternatives and wood stoves for example are forbidden in many areas. Furthermore there is also no environmental forest management in Japan. There is no vision of sustainability and of the entire ecosystem around the forest. Without real governmental action in this sense, some people are forced to act alone and work hard for the environment. Financing must be done by crowdfunding and people with an ecological conscience must hold hands to have enough power. Fortunately some construction companies are setting up eco-friendly branches, using chemical-free materials or local wood. Unfortunately these products are still expensive and many can not afford to use these products. It seems that the government acts more in the sense of the environment, only in a market logic. They are interested in helping companies because those companies pay an income tax. The government is not that interest in low cost or raw materials, used in buildings. There are still many regulations and rules that prevent ecological transition. The current logic is more one of saving energy or energy efficiency than promoting energy and alternative materials. The government is still taking action in the direction of ecology, driven in particular by the Kyoto Protocol, international agreement to reduce greenhouse gas emissions, or by the «Sustainable Development Goals» put in place by the UN. In addition, it seems that the government is conducting numerous experiments on its territory in favor of the construction of ecological buildings, or the use of local wood. Despite these small advances, it seems that society itself is not ready for a real ecological transition in the building sector. Many still want a home already made, choose in a catalog. Many focus on conventional architecture and large construction companies. It seems that alternative and low tech materials such as straw bale will remain marginal and not widely used in Japan.

IV/ Future of Straw bale in Japan

B/ Evolution of straw bale â&#x20AC;&#x153; Maybe many people will be interested in it. But a very, very few, will build it.â&#x20AC;? ( Jinnouchi) The degree of recognition of straw bale buildings now is still low. Despite this, it seems that it is becoming more and more popular in Japan. Most likely, it will continues on its progress and some buildings will be built each year in Japan, by the bravest ones. There will always be resources in straw bales and people wishing to build their own homes or to have a very well insulated house, especially for the mountainous regions of Japan. Whether for straw or other alternative materials, it is certain that the desire to build cheap ecological homes will increase. But it seems that straw bale, in Japan, will remain a secondary material. Because the system around that is currently absent and it will have difficulties to develop. Indeed it is not a country that has in its tradition the breeding of animals and the storage of bales will remain difficult in this very humid climate. The resource will always be present but will have a hard time becoming more popular. This scarcity also makes it a rather expensive product. Too expensive for the most modest households, and not expensive enough for the farmers to really motivate them to make straw bales. In addition, the labor is also relatively expensive, even though it is often done as workshop or participativ construction. It will always be more expensive to build a straw bale house in a country where industrial materials are cheap and easy to set up. Moreover, the price of the land is expensive in Japan, and the high density in the cities do not allow to have wider walls.

â&#x20AC;&#x153; Now I think there is a revival of straw bale in Japan, of people interested for its function.â&#x20AC;? (Holzhueter) In spite of this, the changes in consumption and the increasingly indispensable arrival of an ecological transition are also stimulants of a renewal for straw bale buildings. Rumors indicate that Kengo Kuma, one of the greatest japanese architects nowadays, is making a straw bale building in Toyama. More and more people are training in straw bale construction. This increasing number of straw builders will therefore make it possible to build more straw buildings in more parts of Japan and with better quality. It can also lower the cost of labor and make straw bale construction more accessible. This material is starting to be heavily examined and today we have many analyzes on its effectiveness and its qualities as insulation, resistance to moisture or fire or even earthquakes. These analyzes will make it easier to obtain bank loans or building permits. The straw bale construction is experiencing a real revival for its qualities, no longer as primary constructive techniques but as a real alternative material. It is in this sense that a network is gradually set up, all those who work in straw bale construction know each other personally and can easily communicate. By mutual help between the various Japanese actors, the sharing of analyzes and observations and by communication with the networks of other countries of the world, the construction of straw bale can thus be structured little by little and build a real system in Japan.

â&#x20AC;&#x153; Straw bale is very important for insulation, but in Japan we have a lot of other alternative insulation materialsâ&#x20AC;? (Itonaga) In parallel with the development of straw in Japan, many alternative materials are spreading. Among them we find wood wool, cellulose wadding, cotton. Materials from bio-sourced resources or recycling. The development of earthen construction and the use of clay plaster remain a major challenge for Japan, which needs this storage coat for heat and inertia. Among the new emerging materials, we also find the light straw clay that echoes to the traditional cob. In fact by mixing a large amount of chopped straw with clay, an effective insulation is produced while keeping thin walls. Instead of straw, you can also find light rice husk using agricultural rice waste, or you can also add some lime to protect the insulation from insects or moisture. But the biggest potential in Japan remains linked to wood and to the used of local wood. Indeed, Japan is a forest country with great resources of good quality timber for construction and this is what Japan needs to focus on. Japan today has to recover traditional knowledge and materials, namely wood and clay; focus on its unused resources such as rice-related agricultural waste; or even try to further reused and recycled. By this return to traditions and territories, Japan can thus have a huge potential in the fabrication of an healthy architecture for man and for nature.

Conclusion : When I prepared this research, I was on one side attracted by the work of slow design, which I found beautiful, and on the other hand certain to face a network less experienced than the one I was able to meet in France and Europe. It seemed to me, a priori, that Japan was a country gradually discovering this material, that it gained popularity among self-builders because it belonged to an imaginary of ecology, alternative, and organic aesthetics. This was not completely wrong, but there was something different in this country. While, self-builds straw bale constructions were developed, during workshops or by the advice of some experienced builders. There was also, in parallel, an enthusiasm coming from Japanese architects, teachers and researchers. They became interested in this material and started to experience it and get to know it better. It is this same handful of architects and researchers who quickly responded favorably to my interview request. Indeed, these people, for years trying to improve the living conditions of Japanese homes, have proved to be particularly kind and open-minded. This objective was not easy to achieve, but they persevered and they can now be proud of what they have already accomplished. These builders, architects, professors and researchers all know each other and for some are friends and work closely. But each of their sides they acted to mount a system, to improve the techniques or to make known this material. When I finally met them, I came (for the most part) accompanied by a friend, a student of architecture in Montpellier. He was coming back from an internship with the French Straw Bale Construction Network (RFCP), so he arrived more up to date than me on the conditions of straw bale construction in France.

While I thought I met these people, as a stranger seeking information, these encounters turned out to be true dialogues. I was warmly welcomed in their cities, their offices or even sometimes their homes. We exchanged on our countries, on the respective progress concerning the ecological materials and the development of the construction in straw bale. I also sometimes gave them some documents or technical information about the straw bales, but most of all I think, I made them discover a real additional motivation. By the example of France, where straw bale is becoming very popular and with a solid future as building materials, I have been able to show them that their efforts are not in vain. Others have been able to achieve this progress and have cruelly tipped the scales towards an architecture respectful of the environment and healthier for human. Moreover by this trip to the meeting of its actors, I hope, solidified this network. This Japanese network of straw construction that today is still abstract and not very visible, but can be very easily set up by the proximity of these people. Everyone was curious about the othersâ&#x20AC;&#x2122; view of the future of straw construction, and I hope I have given these people a new spirit, by sharing everyoneâ&#x20AC;&#x2122;s efforts and given an idea of the potential of straw bale construction. One of the goals of this research is to give an account of what has already been done, to prepare for the future of straw bale architecture in Japan.

Resources:

All the photographs are personal and are either from the trip to Japan, or previous experiences related to the material «straw bale». As far as the writings are concerned, the majority draws its sources from personal experiences but above all from interviews held in Japan, with the actors of the construction in straw bale (and which can be found in Annexes). Apart from the personal resources some website allowed me to better develop some comments and information: - https://rfcp.fr/ The website of the French network of construction in straw bale - http://holzhueter.blogspot.com/ The blog of Kyle Holzhueter who made me discover straw bale in Japan and presents actors, buildings and some pages of stories and analysis. Some journals also helped me a lot in my research: - The brochure of the RFCP, Some data are treated in appendices. - The booklet of Slow design, presenting the work of Goichi Oiwa - The booklet of Straw bale Project, Presenting the work of Hideto Ooshima And finally, which was also of great use: - The previous thesis of Kyle Holzhueter, Entitled: «The Hygrothermal Environment of Straw Bale Walls in Japan and Building Practices to Control Interstitial Moisture»

Appendix :

Map of a journey in Japan around straw bale architecture :

RFCPâ&#x20AC;&#x2122;s informations on straw bale material :

Transcript of all the interviews in Japan : Takeshi Jinnouchi, 25th January 2019, in his house near Asahikawa, Hokkaido How did you discover straw bale construction ? In 1996, or 1995, I saw «the real goods» magazine, maybe from California, an alternative lifestyle magazine. And then bought one book of straw bale, red it and built my first building in 1996. And what about this House ? This house was the second one, built in 2006. Why were you interested in straw bale at this time ? Mmmh... I saw the photos of straw bale buildings. And I feel... This is it ! And my wife said «how can it be ? is this true ?». But when I built it, then she also said. «This is it !» Do you like to live in this house, in your house ? Yes ahahah, maybe it is a little bit too small. And also, there are many troubles/problems, because at this time, I didn’t know many things about straw bale or about clay plastering. Do you think a link between your work of forestry and alternative buildings like straw bale constructions ? Before, I wouldn’t imagine that there is a link. But this year, me and my friend, we buy a gasoline engine. We’re going to build a new shell around here, with the wood we cut and maybe use light-straw clay as insulation. That would be a dream for me. Do you think straw bale buildings is adapted to Japanese carpentry ? If the traditional carpenter realizes a straw bale constructions, they can easily build it. If they join the project from the start and think together with the farmer, plasterer, builder. If they work and think together, it can be. What work makes your NGO ? In 2006, we have made a new NGO in Hokkaido, to connect forest and people. There is no good system in Japan for an environmental management of forest. They don’t think for the owner, the forest, the soil, the water, for wind. Many other countries like European countries, they do sustainable management, but in Japan the sustainability is not seen, and that is a very big problem, that’s why I created this NGO. But it is really small, it was very hard, but now we manage 200 hectares around Asahikawa. We do some workshop in the forest to show how to manage a forest, how to make firewood, and also some activities for the children («let’s go to forest»). Is there is a network for straw bale buildings in Hokkaido ? There is no association about straw bale in Hokkaido. But many people come and want to know a bit about straw bale. And we welcome them warmly and for free. That’s also why we built this house.

What was the traditional use of straw in Japan ? In Hokkaido, many people come from Honshu (the west southern part of Japan). Traditionally, they used often rice straw for architecture (thatch). A hundred years ago many people arrived in Hokkaido to live there, then they built the same architecture style as Honshu, a wood structure without insulation and light straw and clay plaster. But now ordinary insulation is glass fiber and plastic sheets inside and outside. No one uses traditional materials and straw. What is the use of straw nowadays in Japan ? They just burn it or just cut and leave them on the rice field. Traditionally, straw was very useful and important in Japan, they made everything with rice straw like shoes, clothes, houses, ropes, bags, etc........ In winter farmers make straw equipment by their hands, very beautiful craftsmanship. But now, no one still uses it. Is it easy to find straw and straw bale in Japan ? There is a lot of straw around fields and farmland. But we don’t have any system to keep it or use it. So it is hard to really use it. Now farmers work for money and economy, then straw is only trash. So it is very hard to take straw. Do you find some baler for rice straw ? Not for rice straw, it is used for grass, not wheat, but now it’s changing for roll bales. Sometimes farmers make weed roll bales. Then it can be sold. But for rice straw, nobody can sell it. Then what did you use for this house ? I used grass straw bales. It is very heavy and hard, but the rice straw is better, stronger against moisture. Have you already built constructions using rice straw bales ? Not for my house, but for other people. But it was expensive, because there is no system around it. Maybe it is more expensive in Honshu. I heard that on straw bale of 80 cm length, 50 cm wide and 38 cm height is 1500 yen. I think it is very expensive. In France it is about 500 yen (4 euros).... Oh really, it is more expensive than California. What was the price of the bale for your house ? Yes, it was for free. But, me and my wife, we take one or two weeks to produce 850 bales. Before they uses baler to make square bale, can’t you find it them anymore ? They are very, very rare, because many farmers use roll bales now. Very few use compact bales. Maybe horse trainers. Is the construction of straw bale made by workshops or by professionals ? I don’t know about Japan, but for Hokkaido there is no professional builder. Maybe in Honshu I know one or two, like Ooshima san. I don’t know the other people, but there are a few. Straw bale constructions are mainly made by self builder or during workshops.

Did Ooshima made a specific formation or have a certification, to be a professional straw bale builder ? I only talk to him by phone, but never met him, so I don’t know How long it takes to make a straw bale house, like this one ? The first straw bale house in 1996, took 3 months to build it, and almost the same for all the others. But for this house, it is not even finished yet, so I don’t know. But for wood structure I order a young carpenter team, they built the structure in 4 or 5 months. Then I fill the straw bale during one and a half months by myself and bamboo mesh on it, this takes two weeks. And at the end to finish the clay plaster, it took 3 or 4 months to make it mainly by myself and sometimes helped by my wife and my friends. And at the end, last year, 40 people came and finish the outside plaster in 2 days. What was the relation between the carpenter and this new material ? what they think about straw bale ? First, they feel really strange. But then they visit the first straw bale house I made, in 1996. It was in summer, very hot outside, but inside the house, it was very cool. Then they find this material really interesting and they said «let’s do it». Did they change the way to build a wood frame, was it easy to combine it with straw bale ? No, it was very difficult. The concrete base is double, the wood frame and windows have to be doubled (double structure), the roof is bigger (cause of snow). The construction of this building was mainly made by you and your wife, do you feel that this type of construction is more available for everyone, like women and children ? Yes, women and children come and they have a lot of fun when they work with straw bale and clay. That’s a really good point of those materials, don’t need special skills or materials. Just do ! Can you feel a big difference by living in a straw bale building ? We feel strange, strange but comfortable. I can’t really explain it, but it is comfortable. Because the house is not quite finished, sometimes cold wind can come inside. Then I can not compare the difference of heating energy spend. But I think it is more comfortable. Have you also same feelings from other people living in straw bale houses ? Maybe, I didn’t visit their house after the workshop, but I have to. Did people around you and your friends are interested in straw bale house when they visit your house ? Yeah, everyone is interested. But did it encourage them to also build a straw bale house for themselves ? Hum... I told them : «This is very hard». The feel interested, but they don’t build. But some of my friends build a new house and used clay plaster also. This is good. For humidity, for inertia.

Do you think this building was cheaper that usual one ? Not so cheap I think. Concrete base is bigger, wood structure is doubled, the roof is bigger. It takes a long time to build it. So not so cheap, but I am preparing another way for wood construction, a more primitive one. I am a forestry worker and I can take long timber, like 10 or 15 meters, bolted together and easily make big constructions. Light straw clay is maybe better for insulation, or straw bale also, I don’t know. That would be a cheaper constructions with the same concepts. Do you think it is possible to make a straw bale buildings in city centers and dense urban area ? Maybe not, because the land is very expensive. Maybe it’s hard to build there. Wild buildings need places to store the straw bales, but there is no land to store them in big cities like Tokyo. And what about public buildings, like schools, in countryside ? Yes, but with Japanese architect law, structure needs to be other material like wood, concrete or steel. But for insulation, straw bale is useful. According to the law, there is no prohibition to use straw bale for public buildings ? Maybe yes, I think. Then, do you know why there are no public buildings ? Maybe people don’t know about straw bale construction. Maybe public people think, how about fire ? about moisture ? etc.... I know it is safe, but maybe the problem is that they don’t know it. Today, in Japan, there are some buildings in straw bale, well built, who can prove that it straw bale can work well. Then maybe, in the future, in 5 or 10 years, do you think in Japan it will be more easy to build straw bale buildings ? Maybe, I think so. Straw, wood and clay constructions are good, but in Japan, making straw bale is too expensive, I think. To make, to store and to bring, and finally to build. There is no system in Japan. So maybe with a system between farmers, builders, developers, government, all mix together, with a good dialogue. But for now there is no real system, and straw bale is too expensive. That’s the problem I think. Maybe, because straw bale buildings in Japan are increasing, then farmers will want to make straw bale, and little by little creates a virtuous circle and thus creates a system. Do you think it can be possible in the future ? In the future, mmmmhh.... I don’t know. I know that the foreign countries, straw bale construction is increasing because of self builders but also with public buildings. But I feel it is different in Japan, I don’t know why. Maybe because of earthquake ? No, no it is not because of this. The main problem is the lack of system, coming from farmers and the government. Japanese government doesn’t know anything about straw bale construction, but if they see how it is increasing in France (also pushed by the government politics for ecology), maybe it will change. What do you think ? or there are too many rules in Japan for constructions ? for earthquake ? I think the lower straw bale constructions, like 3 or 3,5 meters, are good for earthquake.

But what about this building ? It is a strong wood construction, a traditional one, then it is good for earthquakes. What about the comfort of this house ? in summer or winter ? For both, It is always comfortable. What do you think about the future of straw bale construction in Japan ? Does people will also want to build a straw bale house ? I don’t think so. Maybe many people will be interested in it. But a very, very few, will build it. I think it needs a support system to buildings a straw bale as a beginner. But it is hard to support, because of the lack of money, or the lack of support from the neighbourhood, like farmers or builders. They don’t have enough information about where is the straw, where is clay. So, I think it is a little bit too hard to build a straw bale house for them. In France, and Europe, they want to improve the formation and workshops to allow more and more builders to build with straw bale. With this, it will be more easy to find some professionals straw bale builders in every area. What about the formation and workshops in Japan ? Maybe Kyle, in Okayama. He makes many workshops in Japan and also joined a lot. Maybe he feels problems in Japan. We have many rains in spring, in summer, in autumn and a lot of snow in the winter. So, people need big sheds to store the straw bale. Maybe that’s also the problem. Before, I moved a lot of straw bale by truck. It cost a lot, to move to another place, to make bales with the straw, and to move them again. It cost too much. In France, straw bale buildings are increasing because people want to make ecological buildings, don’t want conventional materials, but prefer healthy materials for human and for nature. Is it the same in Japan ? Young people want healthy buildings, well, a part of them. This is very good. Some young people repair old houses or build by themselves, choose to live in the countryside. Grow their own principles, and live together. I think it is a very good movement. And what about the type of buildings they want ? Some of them build straw bale houses, sometimes they use other alternative materials like timber or clay or plaster. In France, we also have other alternative materials for insulation like wood fiber, or recycle paper, etc... Do you have same materials in Japan ? Yes a little bit. In Japan, the government is not good for alternative lifestyle, I say : «fucking Japanese government !». But there is newspaper fiber, a cheap alternative insulation not so much used, but I don’t know about the others.

Koji Itonaga, 8th February 2019, in his office inside Nihon University, Fujisawa How did you discover straw bale construction ? My first time was a straw bale building in Australia in 1998. That place was a permaculture center. At this time I was studying permaculture design. There was a small straw bale storage. Then, did you continue to study it in Japan ? Yes, but in Japan, domestic animal’s farmers make straw ball. But we don’t have traditional straw bale building. Then traditionally what was the use of straw ? For straw bale it was for animal food. But in Japan straw was used as traditional materials for walls, cutting straw and mix it with straw. Straw bale construction need to have baler, is it easy to find some in Japan ? Now ? Now there are a few. The bale is very small, and farmers don’t like it, they want big ones. After messing the straw is more soft for animals. Then it is easier to eat. Do you know vinyl covers ? to protect the straw bales. Now, almost all farmers use vinyl, because there is a lot of rain in Japan. It is the same for rice straw and wheat straw ? Yes the same, maybe half / half. Then, if people want to build a straw bale house, can you easily find straw balls everywhere in Japan ? I think it is difficult, so if we want to build a straw bale building, then we must relocate straw ball (where ?). In my case, in the university, there is an organic farmer who takes care of cows. And He makes the straw bales for them. So we have here, around 10 minutes from here, so we buy him. One straw ball is around 500 yen (4€), maybe it is not so cheap. In Japan, almost all farmers make straw bale, but the purpose is not straw bale building, it is for animals. Yoshimoto, in Toyama, he had to require the straw bale around his area. Our straw bales, three years ago, were bought from him. It was his straw bale, which he has brought here from Toyama. Is the construction of straw bale buildings made during workshops or by professionals ? In Japan, the most famous builder is Kyle. But he is not a carpenter, but a plasterer (painter), so he has some carpenters to help him. Maybe Yoshimoto is a straw bale builder, Ooshima is maybe more designer. Tono Mirai he is architect and builder, maybe also for straw bale. Straw bale buildings are easy to build. Is it easy to adapt the straw bale construction with carpentry in Japan ? In Japan, carpentry is under law. In Japan, we cannot build straw bale as a structural system. Under Japan construction law, it needs a wood structure. Some people don’t care about the law, but with earthquake it is dangerous.

Japanese people, almost all, if they get a house, they want an already made one. The self building system, most of them, cannot understand. For them house needs to be built by professionals. And traditional wood construction is a very hard technique, so carpenters are very important. Then most people and old people will ask a famous carpenter and construction enterprise. In the countryside, they ask the traditional carpenter to build new buildings. Maybe in the future, it will be difficult to develop self build houses, maybe young people. Except for buildings, do you think, people in Japan want to change ? like for plastic ? Now in japan, we have a new association : «low carbon society» with architects, researcher, and construction companies. Now we are in discussion every year, and one person is researching constructors in the company. And he told me, they want to use as half of building materials, the Japanese wood, we have a lot of wood. Because now it is cheaper to import, and that is a big issue now. Before wood constructions was limited to 2nd floor, now it is the 3rd floor. And there are also hybrid wood materials, with steel inside the wood, for big buildings. Some companies are building now with this system. The wood is recycled from Japanese wood. Do you think straw bale will be more popular in the future, in Japan ? I don’t think so. It is difficult. There are 2 or 3 reasons. Maybe there are a few farmers who make straw bales, if the straw bale cost 1000 yen maybe other farmers will start to make straw bales. The straw bale is very important for insulation, but in Japan we have a lot of other alternative insulation materials like paper, wood, and others. Now it is mainly the glass. Do you think it will change ? Maybe a little. You can also use recycled glass. It is not natural, but the system is good. Except straw bale, because the main problem is moisture, and straw bale is too hard for this. I think in France, it is because there is a lot of farmland. In Japan, there is a few baler, they use now vinyl bale. I went in Denmark also, and in a community they use straw bale for energy, for heating. In Japan, straw from the rice production is combined with earth, for the next year production, it is a nice compost. In Japan, we need to use the wood from Japan, for the environment, with wood fiber but also wood panels for insulation. I think between France and Japan the difference are the quantity of materials, in France there is a lot, in Japan, there are a few, because there is a lot of domestic animals also. In Japan it is more important to develop local wood. Some people can still build straw bale building because of its special design and for self building, and I will help them.

Is there some formation, education program, to learn how to build with straw bale ? Now in Japan, we don’t have a regular Japanese construction system. Only have straw bale workshops and buildings. But 13 years ago, a straw bale association make some constructions workshops in Nasu. But now I don’t know. Kyle is developing a Japanese construction system with workshop. And in the university it is not teaching, only my class for now I guess. Do you feel a real difference of insulating with straw bale ? I think it is a really nice material. Do you know thermal conductivity ? Straw bale is around 0,08. Do you think people are satisfied ? Yes, I think. In Japan we have a long winter season. And it is difficult with moisture. Sometimes the plaster breaks and the water go inside the straw.

What do you think is the cause of moisture, do you think it is because straw bale building are not really well built ? I don’t live, myself, in a straw bale house so I don’t know. If the plaster is not well made inside, there is not problems, but outside is a problem. Because we have many rainy days, it is dangerous. Kyle idea was to add a wood facade on the outside, after the plaster layer. With this wood cover it works well. The humidity has danger level on the top and the bottom of the facade. And except moisture, is there other problems ? Yes, Insects. And also mouse. Usually if it is well made, the straw bale doesn’t have grain, and if there is no hole, you don’t have those problems. Yes, I think the join part is really important. And for fire there is no problem because of plaster, and density. My friend tries reed straw, but the reed is really large so it is hard to make straw bale. Do you think we can make straw bale building all around Japan, South and North ? Yes, no problem. But I think the north of Japan is very important, because we need insulation. Sometimes south of Japan is very wet, for a long time, so moisture is a problem. In hot and warm area there are also a lot if insects. Japanese society starts to be aware of environmental issue now ? Now ? Do you know sustainable government goals, it was about 4 years ago, 2015, 140 countries join to agree on these goals, 17 goals. So recently, the Japanese government has been pushed in this way.

Naoko Baba, 9th February 2019, in café Yukkurido, Totsuka, Kanagawa Inside the Zenryoji Temple, discussion with the monk (translate by Naoko Baba) : Naoko baba - He is the person who decides to rebuild this building with straw bale. The japanese Buddhist history is long, and in the old time the Buddhist constructions were organic, didn’t use concrete and chemical, just materials which come back to the earth. But recently, of course, there are some modern materials using chemical materials and not organic ones. Has it been your choice to build with straw bale ? where it came from ? Of course in Japanese architect law, there are some rules, like for earthquakes. So we have to use concrete foundations, but the other materials, he decides to use organic ones. Because of the law, there is a minimum concrete for the base, and with the concrete, they have to use wood panels. But usually the wood panels are used only for this purpose and then they are a waste, but he decides to reuse the wood panels for the ceiling, the unseen part. For the straw bale, you need a lot of people. So for this part (wall) there were 100 volunteers, in the workshop, including the elderly people. And for the café, it was for 1 months and 350 volunteers came together for the workshop. His concepts to build this building was «back to the earth». Because he knows this temple is not permanent, maybe in 100 years, he can break and if that happens, it doesn’t want to make any ecological damage. Inside you see that the straw bale is broke. That wall is with wheat bales and the other building is with rice straw bales. During the construction, because the bale was steel wet, in spring the straw grow and germinate. He imagines, if after the temple broke, still the wheat can survive. It kinds of common artwork to put stones and grass in the plaster. And this is designed by Goichi Oiwa. He is suggesting to see the a video, in Japanese, about the construction of the temple. (Video : hard to understand) Can you see the small window on the ceiling, we open it twice a year, in spring and autumn equinox, the sunset goes threw the window, it is really nice. And it shines on the Buddha statue.

Inside the café, discussion with Naoko Baba : The temple is square, it is more easy to make than the café. The café was very difficult to make on joints, between wall and roof. This building, there is a window to see inside the wall. So it is rice straw bale. I work at the Sloth club, it is an environmental NGO, in Japan, almost 20 years, and we are promoting the slow life movement. Goichi Oiwa is also a member of the sloth club, and we are doing the slow café movement using the straw bale construction. This is the 3rd of 4th café using the straw bale.

And you are a member of sloth club but you work here ? Yes, I am one of the paid staff of sloth club. This café is the refund café, and I am working support, not as regular staff, but I support, do some accounting on the café, and those kind of things. Café Burabura. It is not a take care service, but the organization owner takes care of mentally handicapped groups. So the staff there also has a mental program, they came in the morning, but if someone feel bad at lunch time he go back home. Straw bale house in Japan is new. But using the straw is an ancient Japanese wisdom. Like Shirakawa-go, there is some world heritage town, using straw as materials, for the roof. In Japan, young people, recently, choose tiny house, the tiny house movement. People don’t want to own a house, so they build a little house on the back of cars. Then, they can move when they want, and because it is small, you don’t need to own much and live simply. I heard that Goichi san was invited to Korea some years ago, because young people were interested in straw construction. But I don’t know after if they already have built some café and building or if it is on the way. Is the Sloth club doing some workshops on straw bale ? Yes. First this building was built in 2012, and in 2011 after the disaster, the monk asks the sloth club to do a workshop. And we have done the promoting and promotion, and Kyle comes to say what to do. I also joined the workshop for some days. This was the first workshop. And then a second workshop was made some months after, after the bales dry. But for the main building, it was too professional so they don’t need many volunteers, that is why only hundred people came for one week. Because we are doing an environmental movement, so we wanted to let people know we are doing this project. So we inform them with Facebook, website. The sloth club related building is café slow in Kokubunji, this café, the café Burabura and the Goichi san house. Do you feel that the Japanese government also wants to promote natural building and ecology ? I don’t think so. I think they don’t have consciousness about ecologically friendly construction. But nowadays, there are many people making allergy problems on the skin. Those people want healthy house, even if it is not a straw bale house. So the housing construction companies have an eco-friendly brand. It is more expensive, but using chemical free wood and materials. Regarding the Japanese government they don’t really pay attention, so these buildings and others café don’t have system to apply for support, most of the buildings are self-funding including crowdfunding. And do you think it will change ? I hope. I hope. I expect the government to support those rice cultures, including the construction. So they can grow rice and after harvesting, in spite of just throwing away the straw they can reuse those materials. In Japan there is no big network of straw bale house ? We are an environmental NGO, not only focusing on straw bale so I don’t really have information on that. But I feel that the general public pays attention for their living space. On how they can choose comfortable ecologically friendly materials, and not petrol and chemicals. For workshops, I think we have kind of network. But if you mean a builder network, the sloth club doesn’t have many resources on that.

Because the NGO work also on agriculture and is in contact with farmers, it is a kind of network also. Yes, we are in contact with Goichi san and Kyle, those professional builders, so if someone wants to build a straw bale house we can introduce him to them. Do you think farmers are aware that rice straw can be used to build houses ? I donâ&#x20AC;&#x2122;t think many rice farmers know that. Because to build straw bale house you need square bale, but in Japan, usually they use round ones. I heard the people who have baler, there is not many using square ones. Goichi san knows how many square baler there is in Japan, but cafĂŠ slow used bale from Kansai, western part of Japan, not from here. That means there is no square baler in Kanto area.

Shoko and Hiroaki Yoshimoto, 16th February 2019, in Toyama city center Using an electronic translator, Japanese - French: I studied natural materials at Kassel University in Germany. Nihon university doctor, Kyle, research on temperature, atmosphere, humidity in the straw bale building. With measurement on outside and inside and also on the different part of the wall : high, middle, and down. This will be temperature and humidity data for 2012. The measurement time is once every 15 minutes. Test data from California University, the relative humidity is 80% for a temperature of 10 ° C. There are risks if the relative humidity is greater than or equal to 90%. Mold grows when there is too much moisture, and then straw decomposition begins. The temperature does not exceed even if the humidity exceeds. Since the straw is in the structure, the rain has no effect on it. Straw bale buildings can therefore be built safely in Toyama. This will be the building image of Zenryoji Temple. I brought straw from Toyama. It has been reinforced with bamboo (rods into the bales of straw). I have not been there since it was completed. It will be a therapy facility. This is a facility for children with heart damage. It is the accomodation for them, built in straw bale. It will be the first public straw bale building in Japan. I used it inside the building. Here is the photo once completed. This will be the «window of truth». «Kaya» (traditional roof in straw). In Asian nutmeg. This is made each year. To make a difference of color, and feel the time. This will be the second public building in Japan, it’s a road station and a cake shop. First, there is a small volume. It is load bearing. The place will be Shimanto River, in Shikoku (west). I sent you the address on messenger. In Sendai there is a straw bale house also, a soba restaurant. I used the straw bales on the outside wall for the first time in Japan. We finished with Tosa plaster. «Tosa lime». Tosa is a city in Kawauchi. Here is a photo of a workshop in France, just before I went to Germany. This becomes the straw bale house of Kassel University in Germany. Gernot Minke. This is Minke seminar. This wall is straw bale. And this one is not one, look like straw bale. I put straw and then a metal grill. Do you have any questions ?

How did you discover the straw bale construction? I saw it in a magazine 15 years ago. This made me think of the Sagrada Familia and I thought that the straw had the same design. And so afterwards you went to Germany to study it? I went with a student from Tokyo University and a student from Waseda. There was a publication symposium of a German professor, Gernot Minke. What is the use of straw in Japan? As a plaster, with earth for the walls, the straw is composted, fermented, and mixed with clay. I would like to know more about the straw boot specifically in Japan. Besides the construction, what is the use of straw? Use for livestock and for fertilizers. For the fermentation of Nato (fermented soy). Is it easy in Japan to find or make straw bales? There is a not so much baler to make square bale. Most of the time it is round bales. I borrow the machine from a farmer. How are builders trained in straw bale construction? By all means. There is an association in Fukushima prefecture, where there is a workshop. I learned in workshops in Germany. How many builders can build straw bale buildings in Japan? Kyle, Oiwa sensei, Ooshima in Nagoya. About 4 companies. Afterwards, they will help other people to build, there are also poorly built buildings, dangerous because strongly affected by the rain. Kyle did a job on it. What do you think of the future of straw bale in Japan? Since natural materials are being examined, I think we can now increase manufacturing. A famous architect is building a straw bale building in Toyama this year: Kengo Kuma. Can you give us more information about this straw bale building, designed by Kengo Kuma? It will be built in June this year in Toyama. Iâ&#x20AC;&#x2122;ll let you know. Is the Japanese government in favor of straw bale construction? In Japan it is difficult to use bio materials because the regulations are strict. Especially with the earthquake.

Is straw bale construction gaining popularity in Japanese society? Building a house with natural materials in Japan is now popular. It is difficult to form a lot of people because of the cost. In fact, I think the best way is to build a traditional architecture that matches Japanâ&#x20AC;&#x2122;s climate with natural materials. In Japan we built houses only from natural resources. But now we build with industrial products, we rarely use natural materials. Because industrial products are cheaper and faster. As Japan is narrow, the price of land is also expensive. The thickness of the straw bale wall makes the house narrower.

Kyle Holzhueter, 8th March 2019, in his house near Kumenan, Okayama How did you discover the straw bale construction ? I studied permaculture in Australia, and there I encounter straw bale there, that was in 2002/2003. I knew I needed more building skills, if I wanted to be able to create the permaculture vision I had. So, I thought I wanted to work with a carpenter, and just by chance I participated in a straw bale workshop. This was in United states, in Pennsylvania. I was a graduate student, I was doing a master in sustainable systems, in Pennsylvania. And I happened to participate in a straw bale workshop. And this straw bale builder was looking for an intern. So I interned him for straw bale building during 3 months. Then I worked in his company for 3 months. That’s how I got involved in straw bale building. And then you wanted to use straw bales for permaculture only or for your house as well ? Before doing my internship, I had already applied to come back to Japan, on a scholarship. And while I was working in this company, I got the notification from the ministry of education in Japan, that I had received the scholarship. So I came back to Japan. Part of the application process involved finding a professor in Japan who would supervise your research. (it was «Monbusho») A japanese friend living in Australia introduced me to Itonaga sensei. Itonaga sensei was the founder of Permaculture Center in Japan. In his research studio at Nihon university, he was researching on straw bale buildings. So I entered Itonaga sensei research studio and I started studying straw bale building. Traditionally, how straw was used in Japan ? Actually, straw was a very important resource in traditional Japanese society. They made sandals with straw, boots from straw, they would make raincoat from straw, they would make hats from straw. It was also used as roofing material, for probably half of homes in Japan. The houses suitable for thatched would use thatched because it had a greater durability than straw. But probably for a large portion of the lost wealthy farmers in Japan, straw was the common roofing material. And then when did straw bale was introduced in Japan ? I haven’t looked at it recently. But I think some of the first straw bale buildings in Japan were built around 2001/2002. And if straw bale is not used as building material, is straw bale still useful ? The original purpose of the baler was to store straw as feed and to transport it easily. In Japan, some farmers will do straw bales probably just to deal with the straw. Straw is a bit resistant to decomposition and doesn’t break down very quickly, so a lot of farmers like to burn straw, to get it out of the fields, to make it easier to till the field for next year. Now commonly the combines that are use to harvest rice is to chopped the straw as it is harvested. And that helps break down quicker. So now, straw is not widely used in Japan? No, unfortunately not. It is a valuable resource that is gone out of use.

Is it easy to find straw bales in Japan ? It is not easy. Japan doesn’t have a strong livestock culture. Which mean they don’t have a lot of balers,and if there are not a lot of baler, there is not a lot of straw bales. So domestically the straw bales tend to be rather expensive. It is actually cheaper to import straw bale, that it is to buy domestic straw bales. Another factor of that, is that the rice harvest come during the typhoon season. So generally straw isn’t fill dry. As you said before, in some areas, it is possible to dry them ? Yeah. In Toyama prefecture, with bales of wheat straw. They can do that because they can harvest the wheat before the rainy season start, in June. So they make the bales in early June. Or Hokkaido, which doesn’t get typhoons. Is it easy to find not straw bale, but baler ? I was looking for used baler. I think you can find baler for approximately 1200 dollars. The thing is you will need a traktor then, with a strong enough horsepower to run the baler. But the use of baler in Japan is not common. The construction of straw bale building is more done by professionals or more during workshops ? Almost all straw bale buildings in Japan, the bale are raised as a workshop, in a workshop type format. I mean, it is not a very difficult skill to learn. But it is often under the instruction of someone is experience. And how many professionals can teach this in Japan? There is maybe a handful of professionals builders in Japan, who do straw bale building for income. How those professionals are trained ? I learned in United States. But I think most of the people who built with straw bales in Japan, some of them are selftaught. Actually probably all of them took workshop with the Straw bale building association, which don’t exist anymore. It was founded by Umagami san, in Tochigi prefecture. He was one of the first people to bring straw bale in Japan. He first discovered straw bale, I think in the american south west. He is a designer, an artist, by trade. How long does it take to make straw bale building ? For example, the straw bale building that I just worked on Tokushima prefecture. It is a small building, the floor space is only 10 square meters. It has rather tall walls, with 8 stacked bales high. For that building, all the bales were stacked and the base coat of plaster was made in 3 days, in a workshop type format. In Hokkaido, in 2014, I think, we built a 300 bales, straw bale house. All of the balls were up in 4 days. It was a workshop type format, but myself and some of the staff went earlier, and did some of the critical work before the workshop. But for the rest part 300 bales in 4 days and the base coat of plaster was done in 4 days, and the finish plaster done in 2 days. With probably about 10 volunteers per day. What is the relation, in Japan, between straw bale and carpenter or plasterer ? There is not a lot of overlap. Well, it’s not true, I guess there is some. Toyama straw bale association, is lead by Yoshimoto san and he is a carpenter by trade. There is also a straw bale builder in Yamanashi prefecture or Nagano, I can’t remember his name, maybe Sugiyama san, and he is also a carpenter. And I am a plasterer by trade. I think a lot of the owner builders, or other builders, they are not carpenters or plasterers.

Then, is it easy for the carpenter to adapt his work to straw bale ? Thatâ&#x20AC;&#x2122;s a really good question or issue. How best to incorporate straw bale in Japanese architecture ? Right now, I think the majority of straw bale buildings in Japan, incorporate straw bales with the conventional Japanese timber frame. Not the traditional, the conventional. Which is fine, but in conventional Japanese timber frame, there is big, thick diagonal bracing inside the wall. Which makes it impossible to put the bale between the posts. So the bale need to be entirely on the outside or entirely on the inside. And in that case, you are left with this very large gap between the post that need to be filled with something. In recent years, when I had to combine straw bale with conventional Japanese timber framing, I have filled that gap with stuffed straw. I think this is probably a good option. I think you can also fill that gap with light risk husk, lime or light rice husk with clay, or light clay straw. There are a lot of different options to fill that gap. But still it is an additional step that need to be done if you want to use straw bale with Japanese conventional timber frame. And you can do something unconventional, but that make the permit process more difficult. Did the people feel the difference of heating cost by living in a straw bale house ? Yeah. In 2012, I helped a self builder in Wakayama, named Yamaguchi Akira san, to build a straw bale house. After that I wanted to build an earthbag house and now he is a professional builder of earthbag house, generally working in a workshop type format. He likes earthbag for the artistic quality, he likes the dome and the artistic sense of it. But he says that the straw bale building is way more comfortable than his earthbag buildings. It is warmer in winter and cooler in summer. I think that testifies to the quality of the straw bale buildings. So basically people who live in a straw bale building, or work on straw bale, they are satisfied with it or there is a lot of problems ? I think most of the time they are satisfied. But definitely there are problems. But all of the problems have a reason. So if you can identify those reasons, then you can develop better buildings or build better buildings. You studied with Itonaga sensei on the humidity in straw bale, is there a big issue with humidity in Japan ? I think there is an issue with humidity. But there are ways that you can protect the straw bale walls from moisture or from humidity. You know, Japan has a varied climate, from areas close to the oceans and where we are now, 400 meters elevation, so I mean, I can talk all day about that, it was my research. But do you think the problem of humidity is mainly because of Japan climate or because of construction problems ? I think there is almost no place in Kyushu, Honshu, Shikoku, or Hokkaido that you cannot build with straw bales. I think it can be used almost everywhere in Japan. Okinawa might be a little different. So it is almost entirely a design and build issues, if you correctly design the building. But I think it is not a problem of climate. In fact, it is very effective in mountain areas or colder areas of Japan. Do you think because of the problem of resource in straw bale, is it more expensive to buy a straw bale building ? Oh straw bale is more expensive. The cost of the walls, of the total construction cost will be maybe 20%. Even if the straw bale were free, it will not really change the cost of the building. The problem is that if you want to use straw bale, your foundations tend to be bigger, or there is an additional cost of the foundations, and if you want the same floor space, then your roof tends to be bigger. And that is why the cost increase, with the foundation and the roof.

Do you feel an interest of neighbour or friends about straw bale ? Yes, I think they are definitely interested in straw bale. I think the first people in Japan who adopted straw bale were not the people like me, who are scientific interest in it. The first people who used straw bale in japan were mainly interested in its novelty. It was something new, something different., it was something westerner, it was something DIY, it was something community. And that is what people were looking for. And now since earthbag has become more popular in Japan, the people who were interested in straw bale became interested in earthbag because that’s meeting their needs. It is low skill, low cost, DIY friendly, you can do it yourself, there is a lot of community involved in it. So the people who were more interested in art or community aspect of straw bale have moved on. Now I think there is a revival of straw bale in Japan, of people interested for its function. So you think it will still increase, the number of straw bale buildings in Japan ? I think so. Well, I don’t know if it’s going to increase, but it will continue. They will continue to build straw bale buildings in Japan because there are bales available, and it provides great insulation. And there will always be places in Japan that want super insulation. But I think rice husk is easier to mechanize, easier to accommodate on a conventional Japanese timber frame. So I think there is probably a bigger future for using rice husk, light rice husk lime or light rice husk clay, in Japan. Is there others alternative materials ? Yes, there is light straw clay (mixing straw with clay), those are the main one. Maybe using wood chips, but their problem is that they absorb too much water. And it is quite easy in a laboratory to make samples and have good results. But in the field, when you build an actual wall, it is too long to dry. Do you think it is also possible to build straw bale buildings in city centers ? You might have an issue with compliance of fire coat. But Oiwa sensei will know more about that than me. But we have built some straw bale buildings in cities and there was no problems. I think what is important is that these 2.5cm of plaster over the bales. Because I think the fire-coat requires that. And there is no other legislation that forbids to build straw bales in cities ? No, no. Not even concerning seismic activity ? Yes for sure there is legislation, in Japan, there is «Kabebi Ritsu»(壁率?) which mean the «strength of the wall», that determine how long and how tall it can be. A traditional Japanese timber frame with «Nuki koho and takekomai» and earth plaster, has a Kabebairitsu of 1, and a conventional Japanese timber frame will have one around 1.5 or 2 or 2.5, I can’t remember. And then steel reinforced concrete walls will have a rating of this rating. And that determines how tall and wide a wall can be. But straw bales are generally used as infill materials, not as load bearing, so there is no consequence of building with it. Do you feel that the government promotes the use of ecological or alternative materials ? I was a part of a government program in 2011. There were twenty locations in Japan that got a government granted to build ecological homes. Which were to display for citizens. So citizens could experience and see those houses and say «Hey I want this» and could choose those buildings as opposed to the conventional buildings.

But other than that... There is a government grant to use local wood, where we are here in Okayama prefecture. But other than that, no, there is no government program to use ecological materials. A lot of companies are developing products, that they are claiming to be ecological and pushing that on the market, but, well.... Do you think it will evolve in the future ? I think the government need tax revenue. And they are just interested in having things bought and sold. Because they receive taxes from that. Or they are interested in helping companies to, because those companies pay an income tax. So no, the government is not that interest in low cost or raw materials, used in building. To conclude, what do you think of the future of straw bale building in Japan ? I think itâ&#x20AC;&#x2122;s going to continue, about how it is now. Maybe a little bit more. Maybe I will work on one or two straw bale buildings each year. And maybe in Japan, there is one, two, or three new straw bale buildings per year. I think it will probably continue on that trajectory. And the use of alternative materials will continue to grow. I think on commercial base and on raw base. There will be an increasing need for low cost ecological buildings, so people like myself are going to continue to look for ways to use local and renewable resources. On one hand, and on the other hand, there will be also a growing need and desire for ecological buildings by people with money, so they are going to be able to pay for those commercial products that are going to be healthier or better for the environment.

Goichi Oiwa, 10th March 2019, in his house in Otsu, Shiga Discussion with Goichi OIwa, his son Rei Oiwa, on his son’s wife who also make the translation. Rei - In the traditional Japanese thinking, we believe that every part of the house has a god. So, where gods live is really important. Rei’s wife - Many elements like poles don’t have only structural meaning but also spiritual meaning. Rei- But it’s getting difficult to find very big trees to use as a «Daikoku-Bashira» post, so it’s getting expensive also. Especially for square post. Rei - The location of this straw bale house is also very important. Before he starts to build this house, he considers the view on Biwa lake, and the trees. Goichi - There were two old trees, kaki trees. Rei - Yes he didn’t want to cut those trees, so it influences a lot the location of the house. He designs the house around these trees. Thanks to these kaki trees, in summer, it offers shade. Rei’s wife - So he set up the veranda here, a small garden also, with the view on the lake. Rei - Thanks to the shade of the trees, it is not too hot in the summer and we can enjoy a beer in the verandah. At the end of the house, you can see green trees. This is the limit of our area. Those trees remain green in all seasons They are very ancient trees, this kind of trees existed here 3000 or 4000 years ago. Goichi - Yes, before Buddhism, before Shinto, during Animism. Rei- I think for him those trees are symbols of Animism. Rei- In this region, it rains a lot all year round. Then the straw bale wall also get wet. The traditional Japanese style also uses clay wall. And some old Japanese houses, centenarians, are dying. If the rain touches the clay wall, there is no problem. The surface of the clay plaster, seems to be flat, but actually it’s really uneven. So if the rain always hits the clay, the water accumulates on the surface of the wall. Then, in winter, it is a very cold season, so the water freezes inside the clay plaster and sometimes it will crack. Goichi - It is a very difficult problem. Rei’s wife - And then the water spoils. Rei - This can not happen in a straw bale house. So, to avoid this situation, the roof is longer. Because the Japanese climate is very humid with a lot of rain, the length of the roof is really important. In this house, it is very long, but before this one, he sometimes failed on this part, on the roof. But it is not easy to extend the roof because it becomes heavier. To support it, you can add poles to the outside, but then you also need a base for the poles, which is expensive. Rei - In other projects of his career, in other straw bale houses, he sometimes had failures. Behind, there is a mountain, so he had to take into account where the wind comes from. To build a straw bale house, we have to carefully understand the climate : rain, wind, mountain,etc....

Goichi - This is Gernot Minke’s book, with examples of straw bale houses. There you can see one of my design. I design my first straw bale house, for the first time in 2003.

-Discussion about straw bale network in France and Europe.Goichi - In Japan, the progression of straw bale is very slow. It is becoming more and more popular, but it is still hard to find straw bales and to build houses. Goichi - This house does not have air conditioning. In summer, we don’t need it. This is straw bale power. Rei - Before starting the straw bale projects. He was in Australia to learn about australian straw bale construction. Oh yes, can you explain how you discovered the straw bale construction? Rei- It was in 1999. He received information about a straw bale construction workshop and builders in Australia and United states. So he decided to visit it and learn how the straw bale construction movement is going in Australia, he also went with two friends. After visiting Australia, he went to Humboldt county in Northern California. The people of the community, in this county, buy land to protect it from illegal logging. Many people in this community, with the support of the Energy Foundation, are buying very large land near the pacific ocean. The inhabitant of this community built in straw bale for themselves and have a very interesting farming life. So he was interested and decided to visit this county. He was very interested in the straw bale construction, but besides that he was interested about their lifestyle. This was in 2000. He lived in Tokyo at that time. So after that, he created a workshop with his students on straw bale houses. Because at that time, he and his student were working on the Japanese lifestyle without being dependent of nuclear energy. They studied to reduce the use of electricity in a fashionable way. He specializes in «living», thinking about way of living. He is a member of a group working on this theme, which is based on food, ecological clothes, and alternative lifestyles. Goichi - The young people had very good ideas. Rei - They created «suito movement» (水筒), the «water bottle movement». This is because everyone use bottle of water to avoid using paper cup or pet bottles. But it needs also to be fashionable and cool, so they made nice design. His group was against the existence of automatic vending machines in Japan. There are many in Japan, and even if no one use it, they are functioning 24 h and will consume electricity. To reduce this, they launched this «water bottle movement». This is one of the works of his group of students. Goichi - Then I started researching on straw bales. Rei - As a result he went to Australia and Northern california to learn more about straw bale construction. When he come back, in 2001, for the first time he built a café in straw bale, the café slow in Tokyo. He had no textbook, or manual, or examples. So, during this project (the first slow café) he did a lot of failures. There was an old factory building, it was like a renovation. The advantages of these walls was that they were only inside, so, protected from the rain.

Goichi - They were two different opinions, or you like it or you find that ugly. It was really a new architecture for Japan. Rei- This old «café slow» starts in the center of a residential area. The members of this community were, a bit, crazy groups, fans of karting (?) . So, in the early years, it was really difficult for the café to get customers. Rei - Our family also has a straw bale house, a cottage in the mountains. It is a very good house in summer, the design is really close to this house. My father is a little tired, so he wants to explain to you five points about straw bale construction. Rei - These five reasons are written in his book. This shows how to make a Japanese straw bale constructions. The first reason we built in straw bale house is that it creates a good and truly healthy bio-environment. The second is that straw bale can connect people and the community. Third, is that straw bale house connects people to nature. The fourth, is that the straw bale house connects people and people. It means the people inside the community and the people outside the community, as in the workshops. Goichi - The fifth is story. Rei - Straw bale house is connected to the past, to history and creates new stories for the future at the same time.

Hideto Ooshima, 21st March 2019, in ÂŤstraw bale projectÂť building, Gifu Using an electronic translator, Japanese - French: What I feel after starting this activity: little by little every year, I feel that the awareness of the ecological house and the straw bale construction is on the rise. But still the problem of the cost remains important in Japan. Few people are able to build their ideal home. Have you ever built public buildings with straw bales? I do not know if we can call that public buildings, but I have nevertheless built facilities. Do you think, like me, that public buildings play a big role in popularizing straw bale construction? Yes, it is our goal too. However we started with single houses.

Private discussion. We take stock of my research, the straw in France and Japan. In Japan, if you want to build a house with straw bales, agricultural cooperation will be necessary. It is necessary to build a system little by little. Currently, here it works. What interests me a lot is the strong link he must have between farmer and architecture, in the case of the straw bale house in Japan.

Discussion son straw bale in France. In Japan, there is a smaller scale of the network. In Japan the connection is on personal basis. Personal links are more important. I did not have the opportunity to have a loan for my house because I wanted to build it in a bale of straw. Banks do not want to accept for houses in straw bales. This is because there is no guarantee on the thermal insulation of buildings as well as for lack of example and precedent. Thatâ&#x20AC;&#x2122;s why we do thermal performance analyzes on straw bales in a public facility. We now have the test result. With this it is now possible to receive a loan to build a house. There are many obstacles in Japan.

Discussion on the European network and its data. In Japan, there is a sense of awareness of ecological house. It will be good to have in Japan, a network of straw construction as there is in Europe. It would be interesting to share the results of the different studies.

Discussion on the French network.

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It is difficult in Japan to change architectural laws and it is often necessary to act independently. But it is not so difficult. The Japanese architectural law does not make structural demands so difficult. In Japan clay coatings are used for its ability to store heat. So far in Japan, there was no way to store the heat. And this desire to store heat has not been put forward, even with the environmental laws recently announced in Japan. I think heat storage needs to take on more importance and I think the straw bale house allows for a breakthrough. In Japan too we try to seal more and more the house to isolate it and avoid bringing warm air or fresh air. But I still have trouble with this design. The materials used in Japanese homes generate a lot of harmful substances. Therefore I think that ventilation is very important. But itâ&#x20AC;&#x2122;s a pity to let the hot air escape. Therefore I think that heat storage becomes very efficient. We must also begin to sell houses in straw bales. From now on I have to work hard to increase the straw bale house controls. The first houses in straw bales had the image of self built houses and cheap. So many people have tried to imitate and build their own straw-bale house. However, some houses were destroyed because they did not respect the law. I was also told that the trend in Japan is more focused on the ÂŤearthbagÂť now. Maybe the Japanese have a hard time with thicker and more isolated walls. People who visit straw-bale houses are always surprised by the thickness of the wall. But some people also find it very comforting. The thickness of the wall in Japan is very thin. It is said that in old Japanese houses it is very cold in the winter and very hot in the summer. In Japan each room has an air conditioner.

Discussion on heating and energy in France. In Japan, kerosene is often used to heat.In Japan, laws are strictly against the use of wood stoves, and local laws limit its use. For example, even if I want to use one, I do not have the right.I think Japan is a little late. For this reason, few Japanese are aware of the environment and the housing issue. I think if it changes, people will be more interested in straw-bale houses. Perhaps the Japanese government will change its position if other countries like France are becoming more environmentally friendly. In the current circumstances, people with an environmental conscience work on the sidelines. And that can be difficult if the law does not change. Japan is a strange country, a country where the neighborhood will complain about the use of a more environmentally friendly wood stove. A network should be built on straw bale construction in Japan. Because all those who work straw bale in Japan know each other very well. At some point I think I should build it. I will have to learn more English in order to better communicate with the networks of other countries.

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REAL INTERVIEW.

Using an electronic translator, Japanese - English: How did you discover straw bale ? When I was working on architecture, I felt a little doubtful about making a Japanese house. Then I find straw bale house, seeing it on a TV program. But I think the purpose of the program was to make a house by yourself rather than a special feature of straw bale house. So yo first tried to build it by yourself ? Yes. There are no law or rules of straw bale house in Japan, so I can only do it by myself. Since I am also working on architecture, I do research on straw bale house while adapting the Japanese law. In which year did you start to build with straw bale ? My straw bale projects are in this book. So it was in 2003. All the work listed here are works in straw bale houses. Do you feel that straw bale construction is starting to be more famous here ? I feel that the degree of recognition is still low. But I also feel that recognition is definitely rising from the beginning. Do you think it is especially in this area, in Gifu prefecture ? I donâ&#x20AC;&#x2122;t think it is only in Gifu prefecture, there is also the same feeling throughout Japan. I thought it would be more popular in colder areas, but it seems to be unrelated. Is it easy to find straw bale materials in Gifu prefecture ? I am active in Aichi prefecture. But I am making straw bale with the help of a farmer there (in Takahama) and a few people. When it started it was really difficult to negotiate with the farmers. In order to make a straw bale, I had to leave Inawara (rice straw) with a long size, which put a lot of burden on farmers. I had a hard time with the farmer. By chance we were able to get a good cooperation because in our staff home, there was a farmer. Do you think that straw bale house are also positive for farmers ? Well, farmers make rice and sell it. But we think that it may be somehow good because we purchase the rest of rice straw.

Electronic translator, switching to Japanese - French: You say that you buy the straw from the farmer, yet the farmers still seem reluctant to produce straw bales. Why that ? It is true. People can explain to farmers why we are building houses in straw bales.

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Electronic translator, switching to Japanese - English:

Farmers are relatively helpful when it comes to telling me why I want to make a house. Even if a bad person pays you, it won’t help me.

Discussion on straw bale in France I also studied wheat straw bale and I got quite good results. It depends on the harvest time, but the drying condition is very good. Here, you use rice straw, then how you manage to dry them ? As some farmers, harvest rice after sun drying, then get rice and let them dry in plastic houses during the winter. Japanese main food is rice, so Inewara will increase by all means. Is the price of rice straw bale low or is it expensive ? I think it is expensive. In Japan it is around 500 yen.

Discussion on straw bale price and production in France Rice straw is also used as livestock in Japan. It is old. In Japanese architecture, Inawara is used mixed with soil (clay). Do you think, because the use of less materials and cheap, like clay, a straw bale house can be cheaper than a conventional Japanese architecture ? Most of the cost will be labour cost. So I don’t think it is cheaper. You may reduce the cost by making the construction time shorter. In order to make it easy, we are leading the construction of the house with the client, he can participate.

Discussion on straw bale construction in France Electronic translator, Switching to Japanese - French: In Japan, many promoters make housing without paying attention to the environment. I saw a big problem and found a solution in the house in straw bale. If you compare the construction of Japanese houses to the traditional method, there is no rule as to whether the straw house does not meet the construction standard set by the government. Does the government take new measures for the environment? I feel like I’ve been in a face to face. Then, I do not work on architecture. For example, it is determined that the use of a wood stove is not environmentally friendly. The ecology in Japan will be more about using efficient stoves and air conditioners.

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If I understand correctly it’s more based on energy saving than on alternative energy. Yes. Japan uses with certainty too much energy. That’s why I’m looking to build straw bale houses, use electricity as little as possible, do not produce too much waste, do recovery or reuse, do not make a house larger than necessary. Do you think that the straw bale is also a good material for seismic wood structures? I think it’s very effective. For example, with concrete, the house will break in an instant. There are many earthquakes in Japan, straw is very effective at absorbing vibrations. Have you ever built a load bearing straw bale house here? I have never done it. In Japan it is not recognized by the law.

Discussion on straw bale construction in France / my Research. How did you learn to build straw? At the same time as the others (Yoshimoto / Oiwa / etc...)? At first I relied on American techniques and standards. I learned from someone living in New Mexico. We do research every day by gradually thinking about how to incorporate straw bales. We try to learn from our experiences by gradually correcting the dangerous parts. You always work with the other Japanese actors in the construction of straw? I am not part of a network, but I gradually train my own craftsmen. I hope it will be possible to create a network in Japan. How do you think the straw bale construction will evolve in Japan? by the training of builders? or by building a network of expertise? Since there is still no law in the straw-bale house in Japan. I think the security changes considerably depending on the builder. We therefore train craftsmen who can exercise safely. Are these new artisans trained to build their own homes or to become builder companies? It is in order to build for others. Do you also work with other alternative materials when insulating? I use, for example, cellulose wadding, wood wool, or cotton. Are there manufacturers of alternative materials in the area? Very little. There is no specific place. Is it easy to adapt the straw construction with Japanese frameworks? It is difficult today to build temples or ancient shrines. It is relatively easy to match with the traditional construction method. The difference can be difficult.The ancient temples and shrines have very special structures. However, the method of wood construction is transmitted from ancient times and remains very widespread. Now there is a big difference between the conventional wooden house and the traditional architecture.

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Is it possible to adapt it to the current conventional wood frames? Yes. It is very easy. There is cross beam. Then the straw bale is outside the structure. How is insulated the roof of this building? Thereâ&#x20AC;&#x2122;s just a double layer of thick boards. There is no insulation, but 6cm thick of wood.Then there is a layer of air and then the tiles. Before there was a 120 year old house here, I reused some wood frame elements.

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S t r a w B a l e A r c h i t e c t u r e i n J a p a n 日本のストローベイル建築 r e s e a r c h b y T o m E b e r h a r d I g a r a s h i L a b To h o k u U n i v e r s i t y ENSAMontpellier 2 0 1 8 - 2 0 1 9

A research by Tom Eberhard

under the supervision of Taro Igarashi / Igarashi Lab

2018 / 2019

of Tohoku University