Mortice & Tenon 54 Winter 2013 by M&TOnline

NUMBER 54 WINTER 2013

Andy Hyde Charpentiers Sans Frontières at The Château de Gaillon Dimitri Malko Restoration Work in Japan Joe Thompson The Chappell Framing Square Rebecca Yahr and Christopher Ellis Lichens in the Attic Elizabeth Cunningham Handheld Conspiracy Remembering Ed Levin

At Play Frame 2013. Cressing Temple, Essex

Photos by Fleur Hall

Picture call… Show us what you do and how you do it editor@carpentersfellowship.co.uk

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The Carpenters‘ Fellowship Promoting the study and practice of timber frame carpentry

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CONTENTS 2

At Play Photos by Fleur Hall

I n Site D avid Le viatin

6 Andy Hyde Charpentiers S ans Frontières at The Château de G aillon 1 2 D imitri M alko

R estoration Work in J apan

2 0 Jo e Thompson The Chappell Framing S quare 2 3 Reb ecc a Yahr and Christopher E llis

Lichens in the Attic

2 6 E lizab eth Cunningham Handheld Conspirac y 30

Rememb ering Ed Levin

Copyright Copyright of the Mortice and Tenon is held by The Carpenters’ Fellowship. Copyright of individual articles, illustrations or photographs remains with the authors, illustrators or photographers. Printed by Welshpool Printing Group Severn Farm Enterprise Park Welshpool, Powys SY21 7DF on C o c o o n FSC recycled paper ISSN 1 1368 4612

Editor David Leviatin Sub-editing SOServices Design Mark Clay

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In Site Our annual gathering was a bittersweet affair. The good weather, good beer, good food and good company were all tempered by the news of Ed Levin’s death. Fortunately, his old friend Steve Chappell was on hand. Standing within the ancient oak framework of Cressing’s magnificent Barley Barn, in front of hundreds of timber framers from around the world, Steve introduced Ed to those who didn’t know him and also managed to conjure up his spirit for those who did. In addition to establishing Ed’s person and presence, Steve’s moving words helped sharpen the focus of Frame’s theme: Considering the Past and Imagining the Future of Timber Frame Construction. Later that night I found myself engaged in discussion about the use of CNC machines – an important aspect and recurring theme of our framing future – with a couple of the Hundegger’s leading lights. While my reservations about cutting frames on CNC machines drawn from CAD designs are no secret, my scepticism, and that of many other framers, should not be misconstrued. We’re not Luddites. We are well aware of how remarkable machines are. A machine freed slaves from having to gin cotton by hand; a machine enabled some women in the world not to have to wash clothes in rivers; two machines: a rocket ship and the television, took all of us to the Moon. Bravo! Seriously… The point to consider, however, is the knock on effect, culturally, of our increasing reliance on labour saving devices. Machines designed to save labour can in fact do so literally, making the work of those who have laboured for a living much safer (saving the lives of labourers) and generally making the lives of everyone else in society healthier as well. When the primary purpose of using machines is to make things more cheaply, in an effort to sell those things more profitably, the saving of labour becomes more problematic because it results in the employment of unskilled and inexperienced workers who simply feed machines. Because the making of things well generally takes more time and costs more money than the making of things profitably, the

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former – making things well – involves a few experienced and skilled people working together on a relatively small scale all of whom are practically engaged in and understand all aspects of the entire manufacturing process from start to finish. The latter – making things profitably – usually takes place on a larger scale and involves more people with less experience and skill working separately from one another, usually for rather than with machines, in a highly specialised and differentiated process of which they have incomplete knowledge, little overall understanding and only the most basic interest. Clearly, there is nothing wrong with machines; it’s the way they are used and misused. The problems I have encountered with CAD drawn, CNC machined frames have nothing to do with the technology being used but everything to do with the people using it. Because many of these people are young office-bound folks they have never taken an old building to bits or used tools to make and erect a new one; consequently, they know little about the practical aspects of historical design (timber selection, timber conversion, timber dimensions, timber placement, joint detailing) or much about the practical nature of the interrelated processes of workshop manufacture and on-site raising. Amazingly, given the state of technology and the efficiency of transport networks, a frame can be designed in one place, cut in another and shipped to site without ever having been put together. At the moment this is a curse, but it could very easily become a blessing. Recently I returned from Moscow where my team and I put up and closed in two CAD designed, CNC cut frames. We had nothing to do with the design or manufacture of the frames. Despite being CAD designed in one place, cut on a CNC machine in another and never put together before leaving the workshop, the frames weren’t all that bad. If, however, they had been designed by someone familiar with the do’s and dont’s of historical framing and put together by framers who knew what they were doing before the frames left the shop, they would have been

much better to look at, more structurally sound and much easier to put together. The trick is for craftsmen to begin to do again what until very recently they had always been doing: Know their business inside and out and work with their tools instead of for them. A few weeks ago, I found myself in the McLaren Technology Centre in Woking, Surrey with an astrophysicist friend of mine. Forget about how I got there; what I learned about what they do with carbon fibre and how they do it is something all of us who make things, in whatever material, should consider. The first thing you see when you walk into the sinewy glass and steel Norman Foster structure is a row of cars. The one in front of them all was the oldest: Bruce McLaren’s 1929 Austin 7. The red beauty, its bonnet held in place with a thick brown leather belt that would look great running through the loops of my Levi’s, was purchased in bits by Bruce’s dad Les. Father and son put the car together and Bruce won his first race driving it in 1954. The other cars on display, the actual machines driven to victory by the likes of Hunt, Lauda, Fittipaldi, Prost, Senna and Hamilton, chart the history and the evolution of Formula 1 racing. All of these vintage cars work and are occasionally driven. As we made our way past this impressive row of glistening driving machines (a display of racing history placed front and centre to inspire McLaren’s craftsmen and engineers) and on our way to the state-of-the-art wind tunnel, we could look through floor to ceiling sheets of glass and watch a small number of smartly dressed technicians overseeing the operation of a large herd of CNC machines, all of which were quietly cutting titanium in a stunning production facility. In the wind tunnel, our host, a guy from marketing, explained how everything was tested and re-tested and how McLaren’s engineers could predict a car’s performance before it whipped around the track. The theoretical mind of my physicist friend was tickled to see how everything could be measured, how patterns could be discovered and how risk could be minimised and performance more or less assured through the use of complex equations run by powerful machines. Having spent a good part of my life on building sites, I have grown tired of coming up short trying to predict outcomes. Leaving the wind tunnel, the talk was about F1 cars being fabricated without people and being run around the track without drivers … Light, strong, fast, computer

designed, machine made, remotely operated … Listening to all of this theoretical chatter, especially after seeing the way in which McLaren’s humble hands-on mechanical heritage was celebrated at the front door was getting me depressed. And then we met Dave. Dave is a McLaren race team mechanic, part of the travelling pit crew. Because he had a bad back he was taking time off the road and working in the Technology Centre. He was fiddling with an engine and a gearbox when we were given permission by our host to approach and ask a few questions. Unlike some craftsmen who can be cranky and difficult, Dave was easy going and keen to talk with us. When asked to describe the most memorable mishap, Dave paused and said that each and every race throws up something that they had never anticipated. The physicist looked perplexed. I went for his jugular and asked Dave, “do you mean that with all this hi-falutin’ technology at your fingertips you still can’t get a good idea of what is going to happen on race day?” “Not really,” he said. “There are the crazy things like when a crsip packet or a bird gets sucked up into the car and blows the engine. Or,” he said as he motioned for us to come closer as he separated the gearbox from the engine. “You see that,” he said pointing to a piece of the gearbox that he then pinched between his thumb and forefinger. “You hear that,” he then said as he gently began wiggling the piece back and forth: clink-clink, clink-clink. “What’s that?” I asked. “That’s the Wiggle,” Dave replied. “The Wiggle?” “Yeah . By the end of the race, that piece will be tight; if it starts out too tight before the race, it can get over tight during the race and ruin the gearbox and end our race.” “Is the Wiggle something you can measure?” I asked. “No, it’s just something you learn to know the feel of after years of taking these things to bits and putting them back together again.” What makes McLaren’s method of production special and one that despite their vast oceans of money we can learn something from is their understanding that making things exceptionally well requires the seamless integration of people, machines and materials; of historical knowledge, innovative theory and practical experience all ideally humming along together under one roof, where everyone and everything involved knows how the entire manufacturing process works (and has worked and evolved over time) from start to finish. When machines are used simply as a short-cut, as a way in which to eliminate parts of the making process (either skilled people and/or quality materials) in an effort to cut costs, we all lose out. David Leviatin

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All photos Andy Hyde

The Château de Gaillon is perched above one of the great meanders of the Seine as it winds its way towards the sea through the Upper Normandy countryside. It has probably been a stronghold in the territory for millennia. When the Vikings first sailed up the river in the later years of the 9th century, they almost certainly recognised the strategic importance of its position immediately. It was once held by Richard the Lionheart during the Plantagenet wars against the kings of France. In its chequered history, it came close to destruction many times. During the Hundred Years War it was captured by the English and its destruction ordered, but later spared. Towards the end of its military period it passed into the possession of the Bishops of Rouen and was redeveloped as their summer palace. The buildings were transformed according to one contemporary account into The most beautiful and the finest place in the whole of France. The fortress was reworked first into the flamboyant Gothic style and

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then in the first years of the 16th century, it became the first example of the new Renaissance style in France as sculptors and masons were brought from Italy to re-style the château to the new taste. The antipathy of the French Revolution to the church brought about a long period of destruction which was exacerbated as the château was used successively as a prison, lunatic asylum and barracks and during which, its architectural treasures were systematically looted. A few decades ago, the roof structure of one of the Château’s towers, the Tour de la Sirène collapsed. Enter Charpentiers Sans Frontières and the assembled talents of about forty carpenters and blacksmiths from nine countries! The missing part of the roof carpentry was a ‘cartwheel truss’ or enrayure which dated from 1822. The tower had originally been taller but then reduced by one storey. The framework of the conical roof is quite complex. The 12 principal rafters radiating from the apex

All photos Andy Hyde Technical illustration M Pommier

Cha rp entiers S a ns Frontières at The Château de G a illon A nd y H yde

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Above and left: Historic tools and traditional methods were used to convert the timber.

Right: Scribing a joint. Notice the strings radiating from beneath the timber. These were used as datum in the same way in which a chalked up lofting floor would have been used to layout and mark the timbers .

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Above: The bell tower .

Below: In addition to the main structural repairs missing or damaged timbers were restored using joinery repairs.

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were originally framed into the enrayure with a similar frame above and braced radially to a central kingpost. The structure is bound together by curved purlins which ring the entire framework on four levels. Hewing was soon under way to produce the components of the enrayure. The biggest was the 8.2 metre tie-beam which spans the entire frame. Finding the trees for some of the timbers had been complicated by the need for several with particularly shaped bends. This was to accommodate the eccentric joint at the centre of the enrayure around the king post where the joints are displaced to avoid excessively weakening the tie-beam. The half-ties had to be carefully marked out and hewn to follow these shapes. The timbers had all been hand-felled by axe and extracted by a horse-team from a nearby forest about six months previously. There were no records of the truss before its collapse, so our reconstruction was conjectural. It was based however on the construction of the remaining structure and comparable contemporary carpentry. Its precise form was influenced by the necessity to lift the tie-beam into position through a quite narrow hole in the roof where rafters had rotted around a recently and badly installed roof light. The project lead carpenter Florian Carpentier from Picardy, had constructed a model of the frame. He had discovered that the bends in the half-ties needed to be reversed with respect to those of the existing upper frame, if the tie-beam was to be successfully lifted into position.

A full-size ground plan of the enrayure was set out in the courtyard below the tower using string to mark the centre lines. Once the hewing of the ties and the diagonals had been completed, the laying up and jointing of the frame began. The geometry of the curved purlins was an interesting problem for anyone unfamiliar with complex geometry. The solution was explained and demonstrated by JeanNoël Gascher, carpentry instructor of the Lycée des Métiers in Evreux. Using the trait de charpente as practiced by carpenters all over France, a full size plan and elevation of the roof through the level of the purlins was drawn up. From this, the true shape of the purlins was developed and templates made. The most exciting event of the week was the transport by horse team of the main timbers of the enrayure through the town to the lower courtyard of the château. The only practical route was via a substantial detour. Horse-logger Bruno Buttard drove his pair of Ardennais heavy horses to pull the heavy load, making quite a spectacle as we negotiated our way through the narrow streets of Gaillon, the traffic having been stopped to allow us to pass. We had hoped to do the raising by traditional methods but the scaffold was judged unsuitable for this and a modern crane hoisted the timbers into the roof very efficiently. Some of the lighter

timbers such as the purlins and rafters were indeed hoisted by rope and pulley. The interest in the week was enhanced by the presence of a large group of historians and archaeologists who were attending a parallel series of seminars and observing the carpentry in action to see ‘how it was done’. Several of them gave evening presentations on an aspect of traditional craft or architecture. One of the most interesting was given by Marcin Gładki from Poland. He has developed a highly sophisticated computerised laser scanning system and is collaborating with the Museum Centre of Hordaland (MUHO) in Norway in recording a wide variety of traditional buildings. The scanner is capable of resolving detail to a remarkable degree of accuracy and the method is proving to be a valuable tool in the interpretation and analysis of traditional buildings, even to the level of details such as tool-marks. The Château de Gaillon was reacquired by the French state in 1975 and restoration has been under way ever since. There is still much work to do before it regains anything like its former splendour. Our international meeting of Charpentiers Sans Frontières has made a small contribution to that restoration which is a great monument to the skill of the Renaissance craftsmen of the 16th century. Andy Hyde is a furniture maker currently retraining as a timber framer.

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Re s to ra t i on Work in Ja pa n Dimitri Malko

Japan has a very long history of building with timber. Relying almost exclusively on the use of timber for its architecture, Japanese carpenters have had to find ways of connecting timbers without the use of expensive steel nails and straps. Many dozens of different timber joints were invented and then combined together to create a vast catalog of connections designed to suit a variety of different situations. Many observers believe that the craft of the Japanese carpenter reached its peak in the 19th century toward the end of the Edo Period (1615-1868). During these years, the innovation and ingenuity of the temple carpenters (Mia-daikku-san) brought carpentry to its highest level. Elaborate techniques of drawing along with the perfection of complicated joinery, made it possible for beautifully carved buildings with complex roofs to flourish throughout the country. Recently, I had the opportunity to work as an apprentice for a traditional carpentry company in Japan. The company specializes in the restoration of historic timber frame structures. Two of the projects I

was involved in taught me a great deal about Japanese carpentry in general and about a specific joint in particular. The first project was the restoration of part of an altar in a Buddhist Temple; the second was the restoration of a Bell Tower that was part of a Buddhist compound. In both projects we relied on the use of two very impressive traditional joints: the shiachi-sen and its mitered cousin: the shiachi-sen-dome. The Restoration Projects The shumidan We first encountered the shiachi-sen joint while restoring a shumidan, the elaborate raised timber platform found in the centre of Buddhist temples. Composed of many layers of delicately carved and intricately joined Kiya-ki (a Japanese elm that is red in color, dense in weight and smells awful when not seasoned) the shumidan is a tremendous work of art and craft with an important purpose. The temple’s priest sits on the shumidan while chanting the ceremonial prayers and beating out a rhythmic pace

Images Dimitri Malko

Left: The Bell Tower restored. Below: View of the shumidan before the restoration.

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Above: Cross cut view of the shumidan, showing the build-up of mouldings.

Left: The shumidan, stripped of ceremonial objects, shortly before the repair work commenced

on a delicately carved traditional drum. The shumidan we were going to restore was originally made in the 19th century in the Zenshu-yo style of architecture that came to Japan from China at the end of the 12th century along with Zen-Buddhism. After many years of use (according to the temple’s current priest, his grandfather, who had also been a priest in the same temple, had reached the State of Buddha while sitting in meditation on the very shumidan we were meant to be restoring) the shumidan was beginning to collapse inwards – the two posts that maintained its overall structure had moved over time and resulted in the weakening of the entire ensemble. The company for which I worked was asked to restore the shumidan so that it would be stable and safe for the priest to sit on while conducting the prayer ceremony. After looking at pictures of the job, we realised that it would be tricky work requiring us

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to try and gently pull the structure back together by reinserting all of its many layers snugly back into the grooves carved into its posts. Up for the challenge, our team, a Japanese Shokunin – highly skilled tradesman – and I, set off in our little truck on an early morning for the four-hundred kilometer journey south, through the valleys and the mountains, to a small village in the prefecture of Saitama. We lived at the temple throughout our time working on the shumidan. Once we arrived on the site and had a good look at the shumidan we realised that our work would not be as straightforward as we originally thought. The elm layers of the shumidan had not just slipped from the grooves in the posts, the entire structure had also moved significantly to the right; we would not be able to simply pull the ensemble back together as we had thought.

Images Dimitri Malko

Above: As the shumidan collapsed inward, its many different layers moved sideways and drifted out of their grooves.

When viewed as a timber frame structure, a shumidan is essentially a stack of timber composed of many different sized pieces, or layers, of cleverly joined and finely carved and bevelled elm. Each of the layers is composed of three pieces of elm all of which are brought together using shiachi-sen joints to form a U shape. Theoretically, a shumidan holds itself together without any nails as each layer is set above the previous one, all of which maintain their positions by resting on each other. Only the last layer is fixed into the posts using two hand-made square nails. A very large overhang, at a ratio of 1:2, meant that each time there was any movement from the posts or the flooring, the entire shumidan with all its elaborate layering moved as well. Thus, over time, as all the many interdependent layers moved slightly in different directions they each began to eventually disassociate themselves from their places in the grooves carved into the posts. We could not just pull back the parts in-situ as we had originally hoped, we had to very carefully disassemble the whole shumidan to readjust the layers between them and then fit them back into their original places. The elm being very heavy, we decided to suspend the upper part of the altar from the ceiling above with the help of two great chain-blocks – in this way, we didn’t have to move the upper part of the altar too far away from the lower part of the altar, the shumidan, on which we were working. To have removed the upper

Above: Once the plateau has been removed, the interior structure reveals itself

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The Joints

The Shiachi-sen Traditional Japanese timber frame construction did not use nails for connecting the many different pieces of a timber building. Therefore, a very large range of wooden-joints were invented by Japanese carpenters, some of whom knew and were capable of using more than a hundred different joints. Most of these joint connections were hidden, and generally the connecting system can only be understood once all of the pieces have been taken apart. The shiachi-sen is one of these secret joints. The joint first appeared in Japan in the late 6th century, as Buddhism became the dominant religion in Japan. The joint was imported by Korean and Chinese builders who were spreading Buddhist culture throughout the country by building Buddhist Temples. The shiachi is a variety of Japanese mortise and tenon joint, connecting pieces not at 45 degrees along their length. The joint is held together by pegs in hardwood or in bamboo called sen. The two very short tenons on the female part of the joint are used to hold the joint tight, so it will not split open and loosen the hard-wood pegs. Through its composition the shiachi-sen is made to prevent the two parts from twisting. This wooden-joint is used to connect two pieces together in length, for example it would be used to connect wall-plates. The earliest examples of this assembly are in the 7th century buildings of the Horyû-Ji temple in Nara. The visible faces are connected by a long almost diagonalshaped cut to minimize the gap that will appear after the shrinkage of the wood. The Shiachi-sen-dome In addition to being able to connect timbers together along their lengths, the shiachi-sen can also be used to connect timbers at 45 degrees angles. When it is used in this way, it is called a shiachi-sendome. Dom means miter. This type of joint is used almost exclusively for connecting the different parts that compose the layers of shumidans. It allows the connection of

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Above: A shiachi-sen joint showing the component parts.

Below: A shiachi-sen joint in elevation and plan. This example is used on wall plates in the Horyû-Ji temple complex in the city of Nara.

Above: A new shiachi-sen joint cut for a Buddhist temple near Fukushima.

part of the altar, as opposed to simply lifting it out of the way to give us access to the shumidan, would have been very complicated and risky. With the upper part of the altar secure and out of the way, we began to dismantle the shumidan layer by layer. On the first layer, we added some wood in the groove to create a level base for the next ones. Then, after repairing all of the shiachi-sen-dome joints, we refit each of the shumidan’s many layers back into the grooves in the posts in which they were meant to rest. The last and most delicate step was to lower the upper part of the altar back into place. Fortunately it went back into its original position very smoothly. Our work on the shumidan enabled our team to better understand old building techniques, especially the use of the shiachi-sen-dome joint. The experience and the knowledge gained from that experience proved particularly useful later that year when we wound up recreating a version of the joint we discovered on the shumidan job to connect the sole plates of a Buddhist compound’s bell tower.

two pieces of timber at 45 degrees by using only wood and with the visible face of the joint showing no apparent connection. This joint was characteristic of the skill and craftsmanship of carpenters working during the Edo period. The joint was, and is, quite difficult to realise, because it demands very sharp chisels, concentration and the finest precision. We came across two types of shiachi-sen-dome in the shumidan: one with the peg in the center of the joint and one with two pegs off-center.

Images Dimitri Malko

Above: We found two types of mitred shiachi-sen-dome joints while repairing the shumidan. One using two tongues or sen to lock the joint together and another that used only one sen.

The Bell Tower Soon after completing work on the shumidan we began the restoration of the base structure in a Shiô-ro; a Buddhist compound’s bell-tower, near the city of Fukushima. The overhang of the roof’s eaves was not large enough, and the rain dripping off the roof kept the sole plates damp. After more than twenty years, the structure had been very severely damaged by rot. To connect the sole plates we decided to recreate the wooden joints we encountered in the shumidan. We had to connect four pieces of timber together to form a square and naturally we did not want any visible joints. As an apprentice in a traditional Japanese carpentry company, I thought I had absolutely no chance of doing these joints: only my elderly co-workers could do them, as they worked better and faster than I did. As the five day winter holiday approached, one of the older carpenters had only traced the joints on the

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Left: The Shô-Ro during the restoration; At exactly 8 o’clock every morning, the head priest of the temple rang the massive bronze bell several times.

Hinoki sole-plates. Hinoki is a kind of Japanese cypress, with a distinctive scent. I asked him if it was possible for me to stay in the workshop during the holidays and spend my time making the complicated shiachi-sendome joints. He agreed, but under certain conditions: I would not be paid for the five days; all the joints must be finished and ready to be loaded on the truck, stacked neatly in front of the gates. The challenge was achieved. In January, we put the different elements together and by early February the Shiô-ro was completed. Having participated in these two restoration projects and a few others, I had the chance to have a small glimpse of what the Mia-daikku-san (temple

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carpenters) were capable of doing. Their work demands concentration, humility and many late night hours spent carefully sharpening blades that will assist them in realizing the precise execution of their vision. Despite, or perhaps because of all this attention to detail and focused effort, seeing the result of one’s work is the best reward a carpenter can have. Dimitri Malko trained in France at the “Compagnons du Devoir” (AOCDTF), working on different restoration sites in France and Russia. He spent a further two years in Yamagata, Japan as a master’s apprentice. dimitriomalko@gmail.com

Images Dimitri Malko

Top: The sole-plates with the shiachi-sen-dome before assembling Bottom: The wood-joint after assembly, held tight by two wooden sen tongues made from Japanese chestnut.

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The Chappell U n i ve r s a l Fra m i ng S q ua re To many carpenters, learning how to cut rafters to the correct lengths and bevels is one of those aspects of the craft that you “either love or hate!” If like me you are fascinated by the many different ways there are to solve the problem then the arrival of a rafter square that the inventor of which claims to be “the best square in the universe”is going to be of considerable interest. Squares have been used to calculate the bevels and lengths of roof timbers since the late 16th century in England. The use of the square to line out the lengths and bevels gradually became the dominant method during the 18th century. This carried on for spans up to seven meters or so to the 1970’s in the UK, until the widespread pattern, adopted by both Eagle which later became adoption of the pre-fabricated North American roof truss. Stanley in the USA and Smallwood from Birmingham, The early squares were made out of two pieces of England. wrought iron, fire-welded together, into an “L” by a Historically there have always been differences blacksmith. These often had blades of 18" or 24" by 1¼" between the US and the UK in the use of the square. with a tongue of 12" by 1" and divided off into inches and On the most basic level, there is a difference in the eighths. The 19th century saw the introduction, from the terminology used. For example, the Side Cut in the US is United States, of the steel square, with its 24" by 2" wide known as the Edge Cut in the UK. While there are a few blade and 16" or 18" by 1½" wide tongue, divided off into other linguistic wrinkles, there is a more fundamental inches and eighths, tenths, twelfths and sixteenths. These difference between how the square was read and used steel squares soon came with ready reckoners engraved by English and American carpenters that reflects the very on them, such as Essex Board measure, Brace measure different on-site experiences and challenges they were and the Octagon Scale. most likely to encounter. The first rafter tables that were engraved onto the steel These different experiences and challenges can be square were patented by J.Howard in 1881. These gave gleaned from the pages of old English and American you the rafter lengths in feet and inches or inches and carpentry books. twelfths, for the run of the roof, for the three most popular 19th and 20th century pitches, viz quarter, third and half pitch. This pattern of rafter table, based on simple whole number ratios, was expanded to seven pitches and used by firms such as Sargent and Craftsman in the USA, in the 20th century. Then in 1901 Moses Nichols patented his new rafter tables that were not restricted to the rafter lengths for a few standard pitches but were based on “rise per foot of run” Example of the Sargent square and gave you rafter lengths and bevels for 17 different roof pitches. American books focus heavily on the framing of Seven lines of figures were given, these were: rafter unequal pitch roofs but they pay very little attention length per foot run, hip rafter length per foot run, jack to framing roofs irregular in plan. English books cover rafter edge bevel, hip rafter edge bevel, jack rafter length unequal pitch roofs but they also spend a great deal of at 16" and 24" centres (the rafter length per foot run times time discussing the framing of irregular plan roofs. 16/12 and 24/12) and sheathing face bevel (the reverse This may have something to do with the fact that of the jack rafter edge bevel). This pattern of rafter table, American carpenters, beginning in the 17th century, usually with just the first six lines became the dominant were working almost exclusively on new builds in which

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Images Chappell Universal Square & Rule Co

Joe Thompson

the plan of the building was made as regular as possible to facilitate the more straightforward framing of regularized timbers. Standardizing and regularizing the building process made it easier for young carpenters of different backgrounds and modest skills to make the business of house construction a profitable enterprise Example of the Nichols square patented in 1901. This square increased the number of for developers who were in a rush possible roof pitch calculations from 7 to 17. to knock out buildings that were very much in demand to house the huge numbers of What follows below, is a line by line breakdown of the European immigrants moving to America’s cities and equal pitch rafter table found on the blade of the Square’s also to make it possible for the same developers to face. The table covers equal pitch roofs from 15 degrees stake valuable claims in the sparsely populated western to 50 degrees in increments of 2.5 degrees. To follow territories by building geometrically regular towns of along, you will need a calculator and a pencil and paper geometrically regular stud frames almost overnight. in addition to the Square. We will be cutting a 40 degree The more skilled English carpenters, on the other hand, pitch roof. who were trained in a tradition of scribing were working less on stand-alone regular plan new-builds but rather Line 1 gives us the rise per 1mm of run. on the head-scratching challenge of stitching additions For a 40 degree pitch roof there will be 0.8391mm of onto the already existing irregular plan of centuries oldrafter rise for every 1mm of rafter run. To get the correct buildings that not only may have moved out of regular rafter on your timber angle use 10 on the Square’s blade shape over time but that were originally framed to and 8.391 on its tongue. You can also multiply both follow the irregular lines and angles, dips and rises – so figures by 30 and then mark the correct rafter angle on characteristic of English and European cities, towns and the timber by using 30 on the blade and 25.173 on the villages – that were drawn up in an effort to maximize tongue. every inch of a very limited amount of valuable space. Essentially a way to convert the given angular pitch to a So, what’s so special about this square? rise you can use on the tongue to partner the run you already What can it do that others can’t? And how useful will it have for your blade (all th e figures are given to 4 decimal be for English carpenters? points and the graduations are in 1/10ths). The Chappell Universal Metric Traveller Framing Squares were released in 2012. Developed by Steve Line 2 gives us the length of common rafter per 1mm of Chappell of Fox Maple from Maine, USA, this is a roofing run. The same figure also is used to give us the difference square with a 10 line set of rafter tables. The Traveller is the in length of jack rafters per 1mm of spacing and the top smaller of the two metric squares available; it has a body cut of jack rafter (edge bevel). (or blade) of 500mm by 50mm with a tongue of 300mm For our 40 degree pitch roof the common rafter length by 40mm and is made from 13 gauge, 304 grade stainless will be 1.305 units of length for every 1 unit of run. This is steel. All the graduations are in centimetres and 1/10th of known as the “unit multiplier”. If the span of our building a centimetre (millimetres) in between. is 8.5m, then the run of the building will be 4.25m, or half When I first acquired the square it did not come with the building’s span. To find our total common rafter length its instruction booklet, so I was quite baffled at first where we multiply the roof’s run of 4.025m by 1.305. The result is to start. Then I downloaded the imperial booklet off 5.738m, the length of the common rafter. the website, and that helped up to a point. The metric If the roof has hips and/or valleys and the hip and valley version of the booklet arrived and I could then get going, jack rafters (nothing more than interrupted common but what really helped most was seeing Steve himself rafters) are going to be set out at 400mm centres, the use the square at Frame 2013. His work features a lot of lengths of the first or shortest jacks, the ones 400mm from open valley roofs with framed purlins, often with unequal the valleys and hips, will be 522mm in length or the result pitches, over rectangular plans. The new rafter tables have of having multiplied 400mm x 1.305. been specifically developed to enable carpenters to solve To line out the jack rafter edge bevel use 10 on the these complex interactions and rotations. These visually Square’s blade and 13.05 on its tongue and mark along stunning and layout challenging roofs are essentially a the tongue. feature of the timber frame revival over the last 40 or so years; there are very few historical precedents. Line 3 is length of hip or valley per 1mm of run. For 40 degrees the figure given is 1.644

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So for our run of 4.25m the hip rafter length is 4.25m x 1.644 = 6.987m Again this is the “unit multiplier” or ratio that generates the hip or valley rafter length per unit of run.

This is the other “new” figure that is required at the foot of the hip or valley where it frames into the adjacent principal rafter. In an open valley roof this is where the framing can get busy!

Line 4 is Difference in length of Jack purlin per 1mm of common rafter length and Top cut layout over Jack purlin (Purlin edge bevel) and sheathing offset per 1 unit. For 40 degrees the figure on the table is 0.7660. For purlins at say 2.00m up the common rafter, the purlin length will be 2 x 0.766m = 1.532m. The maths teacher would confirm that to calculate the adjacent side length (purlin length) use the cosine of the angle = cos 40 degrees= 0.766

Line 8 is Working plane top of hip or valley over 1. For 40 degrees the figure given is 0.8600. So use 10 on the blade and 8.6 on the tongue and mark off by the blade. In the UK we would tend to call this the hip rafter edge bevel; hip length/hip run =16.44/14.14 or 10/8.6

Line 5 is the depth of backing and bevel cut per 1mm of hip or valley width. For our pitch of 40 degrees the figure on the table is 0.5103. So for a hip of 50mm width the depth of hip backing is 50/2 x 0.5103 = 12.75mm. We use half the width of the hip, as we are working off the centre line. This figure is the tangent of the hip rafter backing bevel So to set up the saw blade bevel = tan¹0.5103 = 27.03 degrees (see line 10 below) These first five lines are all pretty standard stuff, giving us the dimensions and bevels for the common, hip and jack rafters and purlin length. Line 6 is the housing angle purlin to hip or valley over 1 and hip/valley side angle to purlin header. For 40 degrees pitch = 0.3482 So use 10 on the blade and 3.482 on the tongue and mark off the bevel by the tongue. This is the first of the “new” figures that is used when framing a purlin into a hip or valley. The housing avoids taking all the shear on the tenon and hides any shoulder shrinkage. Old English carpenters would know this bevel as the “Valley over Purlin side bevel” Line 7 is Housing angle of hip or valley to principal rafter or level plate over 1. For 40 degrees the figure given is 0.4195 So use 10 on the blade and 4.195 on the tongue and mark off by the blade, against a level line not the edge of the timber.

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Line 9 is Jack purlin side cut layout angle over 1 and Fascia mitre angle with tail cut at 90 degrees. For 40 degrees the figure given is 0.6428 So use 10 on the blade and 6.428 on the tongue and mark off by the tongue. In the UK we would tend to call this the purlin side bevel; Common rafter length/rise = 13.05/8.391 or 10/6.428 Line 10 For 40 degree pitch roofs the figures given at which to set your circular saw are: 27.034 and 32.798. In addition to the table covered above, there are three other tables on the Square: Unequal pitched with a 30 degree main pitch. Unequal pitched with a 45 degree main pitch. Hexagon and Octagon rafter tables to match the equal pitch table. So all in all a fascinating addition to the pantheon of squares. Very useful if you want to go down the “open valley roof” or “unequal roof pitch” path or if you are most comfortable with seeing roofs in terms of numbers in base 10. Once you have tried this approach you will certainly “never forget it” and as the booklet says “Bastard roofs are a breeze with the Chappell Universal Square”. Joe Thompson set up Sussex Oak and Iron in 1985 and has been working on building and repairing timber frames, mainly in Sussex, since then. He has also been carpenter-in-residence at the Weald and Downland Open Air Museum since 2002 where alongside his other work he also teaches a variety of workshops on historic carpentry practice. joe@sussexoak.co.uk

L i c h e ns in the Attic

Image Rebecca Yahr

Rebecca Yahr and Christopher Ellis

O Rackham, The History of the Countryside, Phoenix Press, London 2000, p87

Above: Wattles are often completely encrusted with lichens. The dust and daub that typically hide the bark easily dissolve in water and lichens are commonly found even on small diameter wattles of only a few years old at harvest.

Image David Leviatin

Most homeowners and building conservators are all too familiar with the issues associated with wasps or mice in the attic, or with playing host to a family of bats. While finding lichens in the loft might leave building owners or managers wondering where to turn, lichens shouldn’t be a cause for concern. In fact, they could constitute an important archaeological discovery. A team of lichen experts from the Royal Botanic Garden Edinburgh is currently building collaborations across Britain to explore the preVictorian landscape using evidence supplied by the lichens preserved in historic buildings. Lichens are largely familiar as the colourful, leafy rosettes that adorn tree trunks or the rich and intricate patterns that encrust old rock walls, gravestones or garden urns. They are also extremely valuable environmental indicators. Because they are very particular about where they grow, lichens can be used to describe and interpret features of their wider context including air quality, local climate, and techniques of woodland management. Oliver Rackham, in The History of the Countryside, claims that ‘examining the timber and underwood of a medieval building may bring back to life the trees and the men of a long-vanished wood’. Lichens can add other dimensions to that reconstruction, too.

Above: Waney-edged timbers are common in historic buildings, especially in roofs, and many still have bark attached, as seen on these rafters and collars in the 15th century Lordship Barn in Essex..

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Image Rebecca Yahr Image Christopher Ellis

Above: Small diameter wood is often covered on two or more sides with bark, as seen in these lichen-encrusted pole rafters from a thatched roof at Cymbeline Cottage, Downton, Wiltshire. A close-up of some of the lichens found is shown inset. They include large leafy types (inset left) and several smaller crusts (inset right). Left: The community of lichens from well-preserved ash staves like this one from Poplar Cottage, Sussex (now reconstructed at Weald and Downland Open Air Museum) allowed lichenologists to infer that climate has changed in West Sussex. These lichens are more typical of the clean-air regions of Cornwall and Devon.

Lichens in Old Buildings? Lichens are tough. They are fungi that farm their own food as ‘crops’ of algae or photosynthetic bacteria housed in their purpose-built bodies. Although some lichens are well known for their ability to live in extreme environments like deserts and polar mountains, many are unable to tolerate major changes in their growing conditions. Lichens on tree bark will die when the trees are cut and converted to timber for construction. However, because lichens are physically durable, they can retain their structures and often remain fully recognisable like miniature dried flowers. And there they stay, sometimes surviving in the timber for hundreds of years, resisting decay and the ravages of time (provided they are not obliterated by paint, sandblasting or stripping). The presence of historic lichens may not be immediately obvious (in some cases a magnifying glass is required to spot them), but they can be found in many different and surprising places on historic wooden building materials. The lichen resource ranges from the bog-preserved Neolithic hazel hurdles that made up the trackways of the Somerset Levels, to the timbers and underwood of historic buildings. Those which grew on big trees might appear on the bark of large waney-edged timbers, especially in out-of-the-way places like roof spaces; or they might completely cover the bark surfaces of the

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hazel sticks used to make wattle and daub panels (see main illustration). Even relatively high-status buildings frequently include roof timbers with small areas of bark on them (above). The odds might seem to be stacked against the preservation of bark in old buildings. Historically, the value of oak bark to the tanneries and the obvious craftsmanship that went into timber conversion are among the reasons why bark might not be expected to survive. Nevertheless, the presence of bark on timber is surprisingly widespread. In a survey of over 40 private buildings all but one had bark and at least half contained preserved lichens. The smaller cross section of rafters and joists in thatched roofs also often means more bark and more lichens (above, top right), and roundwood (wattles or thatching materials) is often completely covered with lichens. Significantly, in old wattles, where the wood has turned completely to dust, an outer core of bark, along with its lichens, can often be salvaged. That fact makes old wattles very valuable, even when the wood is in poor condition. Lichens as Environmental Indicators From an archaeological standpoint, lichens are the premier environmental indicators. Since each species of lichen grows in a specific ‘niche’ or environmental setting, the presence of a particular lichen on historic

building timber can tell us what kind of location the tree was growing in before the timber was harvested. For example, some communities of lichens only grow in agricultural settings where there is strong light. As a preserved archaeological sample, such lichens would suggest that the trees from which that part of the house was built came from a hedgerow. Other species were limited to ancient woodlands and so provide information about the history of a particular area of woodland and how long it has existed in the landscape. Other lichens are sensitive to different forms of pollution, and still others grow in different climates. Finding many different types of lichen in the buildings of a particular village allows lichenologists to piece together the conditions that would have been present in the landscape when the trees were harvested for building, and can shed light on woodland structure and management techniques. For example, wooden building materials recovered during the dismantling of a 16th century cottage from Lower Greensand, West Sussex, included wattle, daub and various timbers. Lichens on these materials were identifiable to species-level and were remarkably well preserved on ash staves (opposite, top left). Significantly, the preserved set of lichens was absent from present-day Sussex, and is now more typical of woodlands in the clean-air environment of West Somerset, Devon and Cornwall. These differences in the lichens present on the 400 year old preserved ash staves and the modern equivalents from Sussex were tentatively attributed to the effects of pollution. Pollution accounts for one of the largest and most important differences between the British environment now and in the pre-industrial period. Lichens and Historic Environments A wealth of historical information can be gleaned from the careful study of preserved lichens in buildings. First, the air was cleaner before the industrial revolution than it is today. Saxon charters frequently noted the presence of ‘hoar trees’: trees used as boundary markers that were covered in bushy, beard-like lichens. In contrast, a survey of lichens from the 1970s showed that huge parts of Britain were lichen deserts. Trees in these areas were completely lichen-free as a consequence of severe air pollution, especially acid rain. Although acid rain has all but disappeared in Britain, lichens are only

now recovering. Indeed, it is still possible to explore urban or suburban British woodlands and see only bare tree trunks which would, historically, have been clothed in a rich variety of lichens. Preserved lichens can therefore provide clues as to the health of the environment in pre-industrial Britain. That information could also be used to set new targets for environmental remediation. The lichens in Britain are probably the most widely studied, and therefore best-known, in the world and the special requirements of each species are readily characterised. A set of historic lichens discovered in an attic can be used to generate a quite specific picture of the type of environment in which those species would be found today. Part of the research for the ongoing project at the Royal Botanic Garden Edinburgh involves comparing modern lichen communities sampled from different settings, with historic communities from archaeological studies, providing a reliable means of inferring what historic environments were like. The distribution and abundance of contemporary lichen communities can be used as a yardstick for interpreting historic communities. A Call to Arms Lichens constitute a rich and valuable historical resource. The potential of that resource is a relatively new discovery, and the lichens in our vernacular buildings have only recently become subject to detailed investigation. Unfortunately, the value and vulnerability of this resource is not yet widely appreciated. All too often, we hear of old wattles ending up in skips or on bonfires. Those involved in working with historic buildings should keep a keen eye out for discarded wattles, for example where an infill panel in a half-timbered wall has been cut open or a complete panel replaced. The Royal Botanic Garden Edinburgh would be very grateful for information about discarded wattles, especially if traces of bark are present on them, and will supply the necessary postal materials for samples to be sent in (please use the authors’ contact details supplied below). Rebecca Yahr and Christopher Ellis study lichen diversity at the Royal Botanic Garden Edinburgh. More information on the RBGE’s research on lichens and biodiversity can be found on the following web page: http:// rbg-web2.rbge.org.uk/lichen/index.html

B J Coppins, F J Rose and R M Tittensor, Lichens from a 16th Century SussexCottage, Lichenologist, Vol 17, 1985, p297

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H a n d h eld Conspirac y The Bridport Conspiracy, a design-build collective based in Dorset that specializes in small-scale projects, is a product not only of its ambitions but also of its environment. We, the two architects Nozomi Nakabayashi and Elizabeth Cunningham, met while attending the Architectural Association School of Architecture’s Design & Make programme in Hooke Park, Dorset during which we met our two other conspirators, timber framer James Stubbs and timber engineer Jack Hawker. During our time in Hooke Park, Nozomi and I found we shared similar frustrations with conventional architectural practice while we were each developing a new passion for making. This combination led to a desire to practice architecture together in a different way and the conviction that the best way to do this was to keep it small and hand made. We each graduated from North American universities several years ago and had worked as architects in a variety of offices all over the world on projects across the spectrum of private and public, from homes to factories and shopping malls, and international design competitions. As we moved through successive projects, various offices and different countries, we both felt an increasing dissatisfaction with the lack of connection to our work, a removal from the artifacts themselves because our knowledge of how they were actually put together was only theoretical. We attempted to address this by burying our heads deeper into construction drawings or working directly with contractors but we both decided that to fully understand construction we needed to learn how to do it with our own hands. To this end, we came to Hooke Park and the Design & Make programme. It was there where we had the privilege to study with great makers such as Charley Brentnall and Charlie Corry Wright who, through their patience and extraordinary skill, transmitted their passion for working with timber and made construction an approachable undertaking. In addition to the formal training, we were also introduced to the world of English timber framing through the professional build team that executed the Big Shed. We saw a whole different means of building delivery that was collective and dynamic. While architects are often passionate about what they do, they are also fiercely competitive, over-worked and suffer from the effects of terribly unbalanced lifestyles.

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Image Elizabeth Cunningham

Elizabeth Cunningham

While the framers at Hooke Park laboured for long hours in often miserable weather conditions and were away from their homes and families, they were obviously excited about the project and worked unfailingly as a harmonious team, addressing their individual weaknesses by learning from each other and relying on each other’s strengths. And at the end of the day they returned to their digs, made meals together, played music and generally enjoyed one another’s company. Around each timber frame structure a temporary but very real community is formed. Their livelihood is, to a large extent, their lifestyle and yet they seem to find it enriching. As architects, our lives have often been totally absorbed by our work but more to the tune of sleepdeprivation and carpal tunnel syndrome.

imaginations as they are of ours. A somewhat surprising development is that we are benefiting enormously from volunteers and we think this has something to do with the compactness of the projects. Building them ourselves creates a certain level of curiosity in itself and a high level of goodwill. We have relied heavily on Jack Hawker’s engineering and tree surgery skills, without which neither the design nor the execution of the treehouse would be possible. In addition, the production of a 1:1 model of the treehouse attracted a lot of attention and the test lift would have been impossible without the people who thought it looked like so much fun that they were eager to help. In the case of the London project, many of the client’s friends have promised to lend a hand which will be invaluable. The small but traditional timber frame will have to be raised using manpower and the more hands we have the easier that will be. Again, the modest dimensions mean that people are not intimidated and want to get involved in what they see as a fun day. Our practice began with a polemic critique of the profession of architecture and building delivery and is unfolding through the design and construction of diminutive structures. Some of the reasons are obvious and prosaic: the financial and legal obligations are minimal which is crucial when starting out on your own. The scale also means that we can prefabricate in limited space and almost everything can be done with power and hand tools. But the element of whimsy is what we most enjoy. While we have to address all of the issues of house-building such as waterproofing and insulation, we have much more room to play. There is an unexpected element of spectacle: people want to see what we are doing and they want to get involved. These tiny buildings are creating their own communities. Image Elizabeth Cunningham

But there were voices of discontent from the framers’ side as well with regard to how late in the design process fabricators are generally brought on board. While they feel an enormous sense of responsibility for and authorship of the projects they make, greater involvement at an earlier stage would undoubtedly result in fewer difficulties during construction and a better design. Often the best design solutions arise after the question, “what is the best way to build it?” has been explored. As we got to know each other the more excited we became about collaborating. It was during these days of conversation and speculation that James Stubbs added his own enthusiasms to the mix and we began to formulate what became the Bridport Conspiracy. We started with a basic premise: a collaborative, hands-on process would result in better, more joyful buildings. Fortunately, almost as soon as we articulated the desire to work together on small projects, we were offered the opportunity to walk the talk. The photographer who recorded the construction of the Big Shed asked us for a small pavilion for her garden in London where she could relax or entertain. Soon after, a writer who lives near Hooke Park and was interested in what has been happening there asked us for a treehouse where he could enjoy his solitude or share some quiet time with his wife. From a practical perspective, the scale of both of these commissions, each approximately 6m², means they can be built by two people in a relatively short period of time. But the tiny size affords us the luxury of more intimate design. For our clients, these are spaces of imagination, objects of desire rather than necessity. We found design clues through relaxed conversations with the clients such as “I don’t want the floor to get muddy” or “I want to take a nap in the backyard”. These sometimes offhand comments that happen in a warm kitchen over a cup of tea or while preparing a barbeque in what will be the building site provided the essential elements from which to begin. These projects do not represent the clients’ life-savings; they are follies which are as much the products of their

Elizabeth Cunningham, along with her partners Nozomi Nakabayashi, James Stubbs and Jack Hawker work together as The Bridport Conspiracy, an exciting new design and build collective. www.bridportconspiracy.com

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Visit www.carpentersfellowship.co.uk for more information on Carpenters Fellowship membership, events and training. – Got a question? Visit the Carpenters Fellowship forum to find advice from practising timberframers, engineers and conservation experts – Looking for consultants, designers or timberframe carpenters? Find a timberframing professional in your area using our business directory ©Jim Black burn The Timber Frame Company 2012

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THE MORTICE AND TENON 54 WINTER 2013

But now I leave my cetological System standing thus unfinished, even as the great Cathedral of Cologne was left, with the crane still standing upon the top of the uncompleted tower. For small erections may be finished by their first architects; grand ones, true ones, ever leave the copestone to posterity. God keep me from ever completing anything. This whole book is but a draught—nay, but the draught of a draught. Oh time, Strength, Cash, and Patience! Moby Dick or, The Whale Herman Melville 1851

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Image: Richard Starr

Ed Levin 17 Ma rch 19 47 - 22 August 2013

TH E C O V E R I M A G E S The front cover Photograph by David Leviatin The back cover Carved Angel, St Andrew’s Church, North Burlingham, Norfolk Photograph by Michael Rimmer