Earth Building Magazine NZ - Spring 2020

...promoting the art and science of earth and natural building SPRING 2020

MYTHS & FANTASY

A story of a small strawbale bach

Hemp House Northland

Raising bales

STRAWBALE WORKSHOP

Hiberna Strawbale

PASSIVE HOUSE

Earth Buidling updates

• From The EBAA, Australia • History of the NZ Standards

Graeme North

Awarded MNZM

OrganicNZ

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rganicNZ OrganicgsNZ OrganicNZ O Raw SOIL & HEALTH

SOIL & HEALTH

-OCTOBER

SEPTEMBER

ASSOCIATION’S

y pi lly Happ pigs organica raising

s Jersey Girl ic A2 milk local organ

Simple spring gardening celery

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TANGATA KAI – ORANGA PEOPLE – ORANGA ORANGA NUKU – HEALTHY FOOD – HEALTHY HEALTHY SOIL

2017

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A balance of bugs

Nature’s medicine cabinet

and how to grow

like this delicious chocolate chilli cheesecake

Organic ‘pest control’ Habitats for hoverflies

otics herbal antibi

ORANGA NUKU HEALTHY SOIL – ORANGA KAI – ORANGA – HEALTHY TANGATA FOOD – HEALTHY PEOPLE

foods

ORANGA NUKU – ORANGA KAI – ORANGA TANGATA HEALTHY SOIL – HEALTHY FOOD – HEALTHY PEOPLE

make your own

SOAP

Fungi fervour

Organic mushroom growing

Passive

Electro-thermal

SOLAR DESIGN

weeding

Great gift idea

Healthier HOME INTERIORS glyphosate

has got to go!

Recipes, prizes, moon calendar and more!

www.organicnz.org.nz

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is a magazine promoting the art and science of earth and natural building.

The magazine will be published three times in 2020: April, July and November. You are welcome to write a letter to the editor or contribute an article or pictures. All advertising, and magazine contributions should be received well in advance of publication – please contact the editor for deadlines.

We prefer to receive all letters or magazine articles & contributions by email or in Word format, though they can also be submitted on disk. Digital

Editor Crispin Caldicott Ph: 09 420 4401 2152 Kaipara Coast Highway, RD4, Warkworth Email: crispin@farmside.co.nz Chairman Pat Mawson Email: rochandpat@gmail.com Treasurer Martin Ulenberg Ph: 021 137 7778 Email: martinulenberg@gmail.com Web site Michael van Beek Ph: 09 433 9747, Hikurangi.

Email: mvanbeek@clear.net.nz

images should be 300 dpi and should be in .tif or .jpg format. Pdf files can be accepted for advertising though must be at the correct size and in cmyk or greyscale mode. The editor reserves the right to edit or abridge any contributions.

When supplying photos please number each picture and a Word document with numbered captions, to make sure correct caption is used on each photo.

Advertising and Promotions Alan Drayton Ph: 09 817 7177 Email: alan@biobuild.co.nz DVD / Video Hire Thijs Drupsteen Ph: 09 401 4737, Kaikohe.

Email: drupsteenthijs65@gmail.com Secretary (Memberships and EBNews) Faith Aroha Gould Ph 021 798 956 Email: ebanzconference@gmail.com Graphic Design Ascension Creative Email: tina@ascension.net.nz File upload: www.ascension.net.nz/upload

Disclaimer: The opinions expressed in this publication are solely those of the individual authors of the articles, not necessarily those of the EBANZ committee. EBANZ accepts no liaibility for material printed.

Copyright 1999 EBANZ ISSN: 1174-6734

Spring 2020 IN THIS

ISSUE FEATURES

42 PASSIVE STRAWBALE HOUSE

NZ ORDER OF MERIT Graeme North awarded MNZM

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MYTHS & FANTASY A story of a small straw bale bach

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EARTH BUILDING UPDATE

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EARTH FOOD

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From The Earth Building Association of Australia Flaky filo pie

HEMP HOUSE NZ’s fourth, in Northland

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HEMPCRETE UPDATE Working solo through COVID19

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EARTH BUILDING STANDARDS 29 The history of NZ’s standards

STRAWBALE WORKSHOP

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STRAWBALE COMPRESSION

41

PASSIVE HOUSE

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BOOK REVIEW

49

WHAT’S GOING ON

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Hawkes Bay bale raising

Achieving compression in a strawbale wall

Check out what’s new in earth building:

www.earthbuilding.org.nz www.facebook.com/earthbuilding

Hiberna Strawbale Passive House Rottenomics

+ digital tidbits

REGULARS

Cover photo: Hiberna two storey strawbale house.

EARTHBUILDING MAGAZINE - www.earthbuilding.org.nz

FROM THE CHAIR

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FROM THE EDITOR’S DESK

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ADVERTISING IN EBANZ

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SUBSCRIPTION INFORMATION

52 SPRING 2020

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FROM THE EDITOR’S DESK I had written this page on the first day of Spring, but due to the need for eleventh hour adjustments in the magazine it is no longer. One thing has not changed however and that is there will be an earth building conference over the weekend of October 31st this year. Everything is in place – venue, food, speakers, homes to visit etc

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bviously, everyone’s focus has been spinning round the compass this year, and the uncertainty generated has caused many to doubt whether it is worth booking travel tickets etc. Well, bearing some other post-election debacle we are on course so please book as early as you can. I hope the fact we seem to have gone all digital with our booking doesn’t discommode the senior generations too much. In theory it makes it all much easier to handle. As with banking today everything is being run for the convenience of the operator … not the customers. I just wonder how much longer cash will be accepted.

If the cover of this issue looks familiar – it is. I have ‘cheated’ by printing our last, digital issue and adding new material.

Loosely, we had decided to print the last issue if we could (it ran into stage four “lockdown” regulations – which also nearly clobbered the olive harvest), and I’m pleased to see there has been a precedent set. A magnificent copy of The Owner Builder (TOB) reached me yesterday and the editor has done the same thing there, and given the Australian Strawbale organisation (Ausbale) genuine value for their input, by printing that section in what had previously been a digital edition. In keeping with Lynda Brighton’s high standards, it is a super issue. In conversation with Lynda recently she pointed out that TOB is unavailable on the news-stands here in NZ because the monopoly distributors ‘pulled’ her title along with a swathe of other minority (sic) journals. We could help - if we all ask our friendly, local paper shop to stock it, they may be obliged to obtain it. I certainly shall.

Straw does seem to be becoming a popular material. TOB devoted much of this recent issue to the medium through Ausbale. Fraser and Faith Gould spent a week in Hawkes Bay last summer learning how to build their forever home, and we publish their excellent account and photographs of the workshop within. I was extremely interested to note the thermal properties of the Hiberna home we all visited last October in Otago. Jessica Eyers has updated her article here which rather remarkably demonstrates how good the insulative properties of a strawbale home seem to be … see page 48 so I don’t spoil the story!

Toby Ricketts has an update on his hemp home construction in the north – all on his own during the period when builders could not join him. I think whether we like it or not, hemp is 2

SPRING 2020

with us as a building material. However, there is controversy as to just how it is used and how much embodied energy is involved depending on what it is mixed with. I hope we will have more writers able to explore this issue in the future, and add value to the knowledge EBANZ holds.

In this issue we are printing the history of the Earth Building Standards – not just for the record but to demonstrate just how much effort has gone into producing these ‘bureaucratic friendly tenets’ which allow home-builders to present plans to their local council and have them approved.

A big thank you to Tatiana Zimina for providing such a fine collection of photographs to illustrate this history with, quite apart from the noble authors – Graeme North, Min Hall and Hugh Morris. We’d hoped to demonstrate the progress of the standards with homes that had benefited directly from them, but it was too complicated and time-consuming.

Instead, Tatiana has illustrated this section with homes that are familiar to many of us, but above all show the beauty and passion that so many homebuilders imbue their houses with once their vision has been unleashed.

I mentioned the olive harvest. Briefly, the Olive Presses had been instructed to close in March, smack into the start of the harvest, for Covid reasons. Incensed by this outrage I wrote to various Government bodies pointing out the implications = no domestic olive oil in 2020! Luckily, my letter was picked up by one of the senior people at MBIE who set in motion the ability of the presses to reopen by taking on-site, individual precautions. The best part however was that I made some new friends, and an article of mine about olives will be the result in a future issue of Organic NZ. Silver linings and all that – and we had a pretty good crop too!

I don’t know what implications - sinister or benign - this early Spring will have upon the performance of Summer, but I noted our Paulownia tree was 75% in flower three weeks early. I look forward to seeing you all at Kawai Purapura again in October.

My thanks as always to all contributors to this, and our previous digital issue.

Crispin Caldicott EARTHBUILDING MAGAZINE - www.earthbuilding.org.nz

FROM THE CHAIR

Spring 2020 TAKE A

This issue has a focus on the completed Earth Building Standards revision, the completion of which was largely eclipsed by the ongoing Covid 19 pandemic. As outlined later in this issue the standards are now published and available through Standards NZ although still to be cited officially by MBIE “as a means” to meet the code.

PEEK INSIDE

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Earth building update...

STRAWBALE BACH The Earth Building Association of Australia (EBAA) promotes the use of unfired earth construction.

Kia Ora earth builders, I have already been involved to varying degrees in three straw bale house consents where the appendix in NZS 4299:2020 Appendix E (Informative section on Straw Bale Construction) has been referenced and accepted by three different councils as supporting the consent application. In practice, the feedback is that consenting officials are treating the revised standards as an acceptable solution and superseding the old standards, which are still the legal standards until the new ones are cited.

So now that the standards revision is published and paid for, where to next for EBANZ? Details of this year’s conference are in this issue and this would be great to place to start some conversations about where EBANZ should focus its efforts.

One of the topics front and centre is natural building education, and how EBANZ can facilitate and support this, especially given the opportunities from the current

disruption to the tertiary sector. There is a discussion currently underway and if you would like to be involved please let me know.

On another note, for those of us interested in composting toilets – our current build has a consented Joseph Jenkins style humanure composting toilet. Mike Copeland of Kiwi Pioneer Co Ltd. prepared the application and it went through consent at Hastings District Council with no issues. If you are not familiar with this system, then this issue’s what to read is The Humanure Handbook by Joseph Jenkins. The e-book is available free online, but it is worth having a hardcopy on your shelf. Search Humanure Handbook to find it. I believe that everyone on the planet should be locked in a room and not allowed out until they have read it!

Please enjoy the great content in this latest issue of earthbuilding!

Pat Mawson

EARTHBUILDING AUSTRALIA UPDATE Earth building is the practice of building using unfired earth material.

Earth is used to construct walls, floors, roofs and even furniture, fireplaces and ovens. It is a building technology with an 11,000-year-old history and tradition, which is used worldwide. Today it is estimated that between one third to one half of the world’s population are currently housed in earth homes.

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The common feature in all earth building techniques is that the material used is subsoil that is composed of clay, silt and sand, where clay is the binder or ‘cementing’ ingredient, and that the drying process is through the evaporative effect of sun drying. The methods and techniques used are as varied as the people, the resources available and the climates in which they are used.

11 Earth building techniques There are at least 12 methods of earth building used and these can be further divided into a total of at least 18 approaches. The following is a summary of what are perhaps the best known of the earth building techniques used in Australia today. This is by no means an exhaustive list, but provides a useful overview and starting point.

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HEMP HOUSE NORTHLAND

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Welcome to the wonderful world of natural building.

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STRAWBALE WORKSHOP

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Graeme North’s MNZM medal was printed on paper and is here proudly displayed on the chest of Rongomaitane, the beautiful taonga that EBANZ awarded Graeme last year.

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EARTHBUILDING MAGAZINE - www.earthbuilding.org.nz

Graeme North awarded MNZM Member of the NZ Order of Merit

For services to architecture and natural building materials

This award is not for me alone. I see it as validation and recognition of a lifetime’s effort that has required the collaboration of many colleagues. The co-operative nature of my work with natural materials has been fantastic, and getting to know all the many people from all round the world who have also been involved, and who have willingly shared knowledge, has been wonderful.

By Graeme North

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atural building materials – these include earth, e.g. mud brick, cob, rammed earth, straw bale, stone and untreated naturally durable timber – are often locally sourced, often abundant, and are non-toxic. Using these materials in my design work has been my life’s work and passion.

has surprised and humbled me how effusive they have been. That’s how I know that this natural materials work is important, even though it has consumed several thousand hours of my voluntary and professional time.

Along with the Earth Building Standards, our book will be my way of imparting what I’ve learned over 45 years to help make sure the next generation have the benefit of good knowledge to help them build well, and to make long-lasting comfortable and durable buildings from earthen or other natural materials that are close by.

Wide scale use of such materials will be a critical part of a decarbonised built environment and these low carbon and carbon-sequestering materials are the way of the future. The Smithsonian Museum agrees – it predicted in 2012 that the first of the forty most important “ Covid 19 prevents things to investiture, but a substitute recognise temporary ceremony was about the organised. future was that sophisticated buildings would Graeme North was to receive be built of mud. his MNZM from the Governor

As to the current housing crisis – there are two ways out of it that I can see. Firstly, enable self-help by facilitating and assisting people to build for themselves out of nontoxic natural materials.

Secondly, the Government needs to build similarly good houses that people can securely rent

General on Friday April the 3rd.

I have kept However this ceremony had on writing earth building to be postponed. However, in standards with keeping with the times a virtual my colleagues ceremony was held between because I know Graeme and his family and a how much this few elegantly attired friends. “ type of building can have a positive affect on people’s lives. Using these materials enables people to long term to eventually own. build houses for themselves – or have them It is cheering to know that Standards built for them – in a way that can have minimal New Zealand and some professional environmental impact. At their best, natural organisations have been of great help e.g, Te materials use minimal amounts of energy and Kāhui Whaihanga New Zealand Institute of processing to win, place and use, resulting in Architects, along with all the other nominating beautiful durable well-scaled buildings. organisations to the past and current earth I am currently working on a book with my building standards committees, as they come daughter, a writer, where we interview people to realize more and more the importance of who live in the houses that I have designed the use of natural materials and their potential over the past 45 years, seeing how much these contribution towards a low carbon built houses have had a positive impact on them. It environment.

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EARTHBUILDING MAGAZINE - www.earthbuilding.org.nz

M yths&Fantasy

A STORY OF A SMALL

STRAW BALE BACH

By Tom Beauchamp

CHAPTER ONE Once Upon a Time a not so young man and his family aspired to create a small sanctuary, a bolt hole, a Bach. So he journeyed to the land of the ancestors, amongst snowy mountains and glacial waters and began his quest…

Charged with idealism and tree hugging dreams with training by the gods of google, Youtube and a weeklong course in Geraldine, thus he began. Inspired by grandparents of old who built the first house on the lake, pick, shovel and rake he toiled under the hot Mackenzie sun. But camping on site with a young family in the mountain climate was a hard task master, wind ripped the tents, rain pelted and “summer” mornings were often frozen.

Progress is slow for the inexperienced and distracted, a practice hut was built whilst waiting for engineers, heads were scratched, sunset walks were taken and pizza consumed.

Time, and money passed. Half a year and $100,000. Was there a finished gem? A masterpiece of straw bale architecture? Even four walls and a roof? No - and yes. There was a ten square meter hut, a slab and an empty bank account.

Photos - opposite page: 10m Practice Hut with “Hast Eagle” mural .

This page - left: Max Beauchamp and neighbor - Mila enjoying soccer on the Bach Pad .

Right: The concrete slab poured.

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CHAPTER TWO A year or two passed, life continued in other parts, our hero, needing more knowledge apprenticed to the world of high viz haters of mainstream construction. He worked, he learned, he saved, he still dreamed.

Once again he set out, this time like Odysseus leaving wife and children behind. But in the meantime, a brother had made the hut his home. Had he escaped? Had he run away? Or was he running to something, finding solace and a sense of place? But he was haunted and troubled, and the two brothers clashed.

Still, progress was made. Wielding nail gun and skill saw the shape of it began to emerge, a roof topped framing. Then the coffers ran dry again, and it was time to return home to lick emotional wounds, leaving things braced for the winter.

Photos - this page: 10m Practice Hut in progress.

Opposite page: Tom Beauchamp applying lime rub coat over earthen plaster mural on the Bach

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CHAPTER THREE The final push began on a New Year’s Day. This time it must be finished and rented, or the new mortgage will not be paid, the golden fleece not won and the Queen mightily pissed off!

This fresh road was populated by many a character - Woofers of the useful and useless variety, psychedelic wielding mystics, religious oracles, professional plasterers, satirical sub-contractors, sirens, saints and sinners, clowns and craftsmen, old friends and new from all corners of the world, throwing straw bales mud and lime, wrestling with materials to create form.

Slowly, finally a house emerged. Was it a finished gem or a masterpiece of straw bale architecture? It was … my first one, it felt like an epic saga of mythical proportions and now it is a home for other people, and now I am home, and now I am to start another home… “once more unto the breach, dear friends, once more.”

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Photos - top left: The interior lime plaster in the bathroom by Liam Flannery of Geraldine; Top right: Scarlett Beauchamp / childs play plastering; Below: The finished Bach.

EARTHBUILDING MAGAZINE - www.earthbuilding.org.nz

Thanks to The Owner Builder for permission to re-print this article.

BE INSPIRED – REAL STORIES ABOUT REAL OWNER BUILDERS

213 – JUNE/JULY 2019

$9.95

Earth building update...

The Earth Building Association of Australia (EBAA) promotes the use of unfired earth construction.

PASSIVE SOLAR

Earth building is the practice of building using unfired earth material.

Earth is used to construct walls, floors, roofs and even furniture, fireplaces and ovens. It is a building technology with an 11,000-year-old history and tradition, which is used worldwide. Today it is estimated that between one third to one half of the world’s population are currently housed in earth homes.

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u

LOW WASTE BUILDING

The common feature in all earth building techniques is that the material used is subsoil that is composed of clay, silt and sand, where clay is the binder or ‘cementing’ ingredient, and that the drying process is through the evaporative effect of sun drying. The methods and techniques used are as varied as the people, the resources available and the climates in which they are used.

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HEALTHY HOME

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STARTING OUT

Earth building techniques There are at least 12 methods of earth building used and these can be further divided into a total of at least 18 approaches. The following is a summary of what are perhaps the best known of the earth building techniques used in Australia today. This is by no means an exhaustive list, but provides a useful overview and starting point.

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Mud brick or adobe

Mud brick is the most popular name used in Australia to describe bricks made from various compositions of soil with water, which is mixed, moulded and dried at air temperature through the evaporative effect of the sun during the brick production stage.

There are almost as many ways of making mud bricks as there are mud brick makers. With puddled mud bricks, the moisture content is quite high and the texture is that of mud or dough. The material is poured into or moulded in simple bottomless moulds. The mould is often lifted off immediately and the brick left to dry through evaporation.

When dry, mud bricks have a density of around 1750kg/m3.

With pressed earth bricks, moisture content is lower and the consistency is that of damp soil similar to rammed earth. The material is pressed into shape using a hydraulic ram that is released immediately, with the bricks then moved to a drying area.

When dry, pressed earth bricks have a density of around 2100kg/m3.

Rammed earth or pisé

Rammed earth uses damp or moist earth, with or without any additive, which is then rammed (tamped) in place between temporary moveable formwork.

It is a solid masonry wall which does not have, and does not need, any cavity.

Since the 1970s, cement has been used as a stabiliser in rammed earth; with

Photo courtesy: Rob Hadden

Pressed earth bricks

Left page: Western Australia leads the world in modern cement stabilised rammed earth construction. Above: Cob, sometimes called ‘sculptural adobe’, can be free formed in situ and trimmed to shape later. Below: Mud bricks are made with a variety of methods and consistencies, but all are air dried.

the addition of a waterproofing additive, stabilised rammed earth has proved itself capable of competing with other forms of masonry walling.

When dry, rammed earth has a density of around 2100kg/m3.

Cob

Cob is similar to rammed earth in that it produces a monolithic or one piece wall, though it is different to rammed earth in two ways. The earth material used has more clay, and straw is added to reduce the potential for cracking as the wall dries through evaporation. The process requires less water than in mud brick making though more than is used in rammed earth.

The wall can be free formed and trimmed to shape later or built within simple shutters. It isn’t so much tamped but pressed gently or worked into the wall until a lump (or cob) of earth material becomes part of the wall.

When dry, cob has a density of around 1450kg/m3.

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Photo courtesy: Rob Hadden

Wattle and daub

Wattle and daub (above left) is an earth building technique that, like all of the above techniques, was popular in the early Australian colonies; it is rarely used here today although it is still popular elsewhere.

A timber frame is prepared with timber lattice, often using Acacia sticks woven together, before a mixture of wet clay, dung and straw is daubed (placed by slapping handfuls) onto each side of the lattice. Density will depend on the size, amount and spacing of the lattice and the amount of straw or other fibrous material added to the clay.

Light earth/clay straw

Light earth (above right) is a technique that is relatively new to Australia. It was first popular in much colder climates though it has found some popularity in colder parts of Victoria, where it is being used to reduce heating loads and more easily complies with energy regulations.

Light earth is produced through wetting straw with a wet clay slurry that

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is gently tamped into temporary forms between a timber stud frame. It is often finished with earth render inside and clay or lime render outside, completely covering the timber frame in the process.

When dry, light earth/clay straw has a density of 600kg/m3, which is too weak to be loadbearing and is therefore better used as wall infill between framework and for internal walls.

Earth render

Earth render is a covering layer composed of clay, sand and silt, often with the addition of dung and sometimes lime. It can be used to coat some forms of earth wall, especially the lightweight (light earth) methods, as well as other natural building techniques such as straw bale construction.

Stabilised vs. unstabilised When clay is the only binder then the earth building technique may be called unstabilised; this is the most natural form of earth building. Stabilisation refers to

the process of putting additives into the mix, which otherwise is just earth (with clay) and water, with the water content varied to suit the construction technique.

Stabilising additives can include cement, lime, bitumen, plant based products and sometimes even modern chemicals.

Unstabilised mud bricks and rammed earth are by far the most common worldwide building techniques, of all building techniques. In Australia, stabilised and unstabilised mixes are used in many different earth building techniques.

Thermal performance All earth wall material can be optimised for thermal performance by reducing the silt, sand, gravel components of the earth wall material mix and replacing some of it with fibre or lightweight aggregates like pumice, plant material, sawdust, grains or expanded/aerated glass.

Mud brick and cob can have their thermal mass reduced to as low as

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1000kg/m3 in order to reduce thermal conductivity. However, this also reduces heat capacity which is a valuable attribute for energy efficiency, especially if designing to negate the need for cooling in hot weather. Good thermal mass design, construction and operation can negate the need for air conditioning.

In traditional vernacular architecture it was common for lightweight techniques to be used in cooler climates and heavier techniques to be used in hotter climates.

The good sense of ancient design is confirmed by modern modelling of passive low energy architecture.

Rammed earth can have a density of 2350 kg/m3 to 1700 kg/m3. Rammed limestone typically has a density above 1750 kg/m3 and, being white, is quite reflective. Generally for rammed earth, 2100kg/m3 is a common ‘mid range’ figure. This is with ‘regular’ earthen materials; specialised materials such as scoria and pumice can give lower densities and better insulative properties.

Generally speaking the denser the material the more ‘thermal mass’ it has, which is fundamentally its ability to store heat (or cold) energy; the less the density the more insulative a material is, providing a better barrier to the passage of heat or cold. One secret to good design is the strategic placement of high thermal mass (dense) and insulative (lightweight) structures to achieve optimal or designed temperature management conditions, which require minimal – or ideally no – artificial or external heating or cooling energy. The easiest way to introduce thermal mass is by having more walls, by including internal earth walls or increasing the thickness of the walls.

Insulation rating With passive low energy architecture and high thermal mass, well ventilated free running unfired earth buildings can and do provide good comfort conditions with near zero energy input. Built with local materials and local labour, full thermal comfort is achievable. Achieving a nil air conditioning load in summer is common. Achieving a low winter heating load is possible, with a small source of warmth from a fire, solar or other resulting in low energy living.

The Australian National Construction Code (NCC), administered by the

Australian Building Codes Board, currently unfairly favours insulation rather than thermal mass. It defines and tabulates and sets minimum insulation levels in parts of buildings in the NCC, but does not mention the words thermal mass once. The scientific truth is that the ideal thermal home – or even a fair thermal performing home – needs a combination of insulation and thermal mass, and that the combination required depends on the location, orientation, design, etc.

With the NCC so skewed toward insulation, the insulative properties of earth walls have been investigated by earth wall builders. Lower density earth walls generally give better insulation but lower thermal mass, while higher density walls generally give better thermal mass. To achieve a better insulation rating, modern rammed earth walls can be built with a layer of insulation (typically foam) within the wall, providing both high insulation and high thermal mass, all in one wall.

Earth building is an appropriate, renewable, sustainable technology.

Appropriate technology Earth building is appropriate technology because it is simple and available to everyone – poor or rich alike.

The material is durable (100-400 years plus proven in Australia, Europe, England, Middle East) offering longevity rivalling modern western housing (25-50 years in Australia).

Earth building is adaptable, able to be used for footings, floors, walls and roofs by using different techniques. It is flexible because it can be moulded and shaped when wet, rammed and pressed when moist, and then hardens in the sun so that it becomes durable. It can be carved, shaved and sawn when dry. The surface (if unstabilised) can be wet and reworked to a polished finish if required. It can be used to create buildings of any shape or style.

Earth building is raw and natural, has low embodied energy and can be used to achieve thermal mass and insulation by adjusting its density and thickness.

The material is non-toxic, non-allergenic, controls humidity, is fire, rot and termite proof and therefore earth can be used

to create safe and healthy buildings.

Earth offers great sound isolation and is effective in screening (reducing) high frequency electromagnetic radiation (Building with Earth, Minke, p.33).

Many designs and methods of using earth have been developed around the world to suit various climates and cultures. Earth is a very attractive building material, in harmony with the local environment from which the material was sourced, especially when used with other locally available, natural building materials. The aesthetic beauty and comfort can be further enhanced if local vernacular building styles are used.

Local indigenous or traditional building styles often use climate responsive designs and are appropriate in relation to other environmental factors, like weather and natural hazards.

Renewable and sustainable Having a minimal carbon footprint, earth building is renewable technology.

The material is often simply ‘borrowed’ from the earth for the life of the building and (unstabilised) can be reused and recycled indefinitely as a building material or returned to the earth. The energy used to dry the earth into bricks or monolithic walls, floors or roofs is ‘free’ solar energy, as the earth is sun dried through evaporation. The thermal mass of earth can be used to store both warmth and coolth, balancing diurnal fluctuations in temperature in all seasons.

Earth building is sustainable technology. The use of raw unfired earth as a building material dates back to 9000BC and today it still houses one third to one half of the world’s people. The material is abundant and widespread, uses very little energy in the entire process from raw earth to building, is durable, and its properties make it an excellent choice for climate responsive buildings. These buildings achieve thermal comfort and a degree of ‘free’ running through consideration and selection of the appropriate design method for the location.

The sustainability credentials of earth building outshines any modern material in any life cycle analysis; from the embodied energy in creating the building through the reduced energy used in its long life, in maintenance, heating and cooling, to demolition and reuse.

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For a more comprehensive picture, read any of the natural construction books

by Gernot Minke, in particular ‘Building With Earth: Design and Technology of a Sustainable Architecture’, Birkhäuser (3rd rev. ed. 2012, ISBN 9783034608220).

Green building Earth is possibly the ultimate green building material.

• Meeting the challenges of comfortable safe buildings while reducing the energy used in construction, heating and cooling of buildings, improving indoor air quality and longevity of buildings and reducing toxic waste to landfill.

This article first appeared in BuildIT Builders & Renovators Resource Guide March 2019.

The 2019 EBAA Conference is being held at the Bamarang Bush Retreat in Nowra NSW, from 27-29 September 2019.

The theme is ‘Achieving high thermal performance, comfort and sustainability with unfired earth products.’ Friday will include lectures from experts and discussions with all. Saturday is reserved for workshops and demonstrations, to learn how to build earth walls, to make and lay mud bricks, to build rammed earth walls plus other earth building techniques. Sunday will involve visits to nearby earth built projects in mud brick and rammed earth. All welcome.

• Raising the living standards of poorer people and maintaining our own without depleting resources, increasing environmental degradation and loss of biodiversity.

• Future proofing our buildings against spiralling energy costs and shortages.

• Building homes that allow us to enjoy our existing lifestyle and reduce our need for fossil fuelled energy and greenhouse gas emissions.

EBAA believe it is exactly what the world needs today to provide safe, durable, comfortable and desirable homes. Those who have owned or lived in an earth home would know and appreciate this. It is a technology that is ancient yet still most relevant.

Build of earth for the Earth. u

Links & resources u

Earth Building Association of Australia 0429 321 104, www.ebaa.asn.au

EBAA EBAA (Earth Building Association of Australia) is a broad based organisation which has members that include builders, specialist contractors, tradespeople and owner builders, specialist manufacturers and suppliers, architects and designers, consultants, enthusiasts, educators and students, with a common interest in the use of unfired earth.

The formation of EBAA commenced in 1990 at a gathering held in Maldon, Victoria. A subsequent meeting took place in Mildura, Victoria in 1991 which elected the first Committee of EBAA. Since then the primary focus of the Association has been communicating constructively with all levels of Government concerned with the regulation of building practice in Australia as well as educating and informing our members and the public.

Our association has a strong national focus and is the peak body for earth building practitioners, both private and commercial, in Australia.

Membership is open to all with an interest in earth building.

Aims and Objectives • To represent the interests of members in the advancement of unfired earth technology .

• To promote the informed use of unfired earth as a building material within Australia.

• To establish an information and referral network for those wishing to use earth within the building industry.

• To uphold the interests of earth building in public or private forums.

• To act as an information source in any process to establish rules, regulations or code of practice which effect the use of unfired earth as a construction material.

• To promote earth building technologies which are environmentally benign.

• To liaise with other groups or individuals, both in Australia and internationally, who have interests in promoting earth building.

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Flaky Filo Pie with fennel chips ine By chef Anna Valent

The weather is warming up, but still cool - and I’m still enjoying nourishing, warming meals. This recipe combines the bountiful pumpkin harvest that we’ve grown over the summer together with lovely flaky filo!

Yes, it makes a big mess but it’s so light and crispy it’s hard to beat.

Keep well and safe in these times, and enjoy the recipe.

We will make this in a roasting dish so it is not too fiddly. The best way to work with filo is to have all the components ready before you embark on assembling it.

Remove the filo from the fridge at the last minute and work with it straight away; there is no need to cover it with a damp tea towel unless you have to leave it.

For a vegan option omit the egg step of the recipe and double the chickpeas, these could be mashed roughly before adding.

Vegan/Vegetarian Serves 6

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ROAST PUMPKIN SLIVERS

FILO PIE

½ crown pumpkin, scoop the seeds out of the pumpkin and slice it into the thinnest slices you can. I use an Asian cleaver for this – the bigger the blade the better for pumpkins. You can remove the skin if you wish.

Prepare the roast pumpkin slivers.

1 stalk rosemary, leaves roughly chopped

Toast in a small pan until golden brown:

Melt: 200g butter or olive oil Brush a 20cm x 30cm roasting tray with the melted butter. Then set aside.

¼ c sesame seeds

Heat the oven to 200°C. Put your prepared pumpkin and rosemary in a bowl and toss with:

Grate: 200g cheese, dairy or alternative Prepare:

1 T olive oil

2 avocados, halved and stone removed

½ tsp salt and cracked black pepper Line a large roasting tray (you may need 2 trays) with baking paper then spread out pumpkin in a single layer. Roast for 25 minutes, turning after 10 minutes.

Squeeze over the avocado halves: juice of 1 lemon or lime Set the avocado aside, sitting in the shell ready for the assembly of the pie.

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For more food nspiration, recipes, or to order hardcover Autumn/Winter, or Spring/Summer cookbooks and e-books, please visit www.theveggietree.com or www.facebook.com/theveggietree

FENNEL CHIPS

roughly in a mortar and pestle or whizzed in an electric grinder 1 T olive oil ½ tsp salt and cracked pepper

Fennel is great for your digestion and its warm aniseed aroma is a tasty addition to your oven chips.

Heat the oven to 190°C (same as for the filo pie). Take your largest roasting tray and add: 1T rice bran oil Place the roasting tray in the oven to warm up.

Prepare: 5 medium-sized Agria or other floury potato, scrubbed clean then sliced into chips of similar size 2 tsp fennel seeds, toasted and ground

Add to a large bowl: 350g ricotta and/or crème fraiche or 350g firm tofu, crumbled 200g feta, dairy or alternative, crumbled ½ c fresh parsley, finely chopped 1 clove garlic, crushed 1 tsp salt ¼ tsp cracked pepper

Put it all into a large bowl and toss to coat the potato chips with the oil, fennel seeds, salt and pepper.

Take the hot tray out of the oven and carefully add the chips into it, being careful not to splash the hot oil. If you want to use kumara chips along with the potato, add the kumara to the roasting pan 10 minutes after adding the potatoes. Roast for 45 minutes until golden, turning a couple of times during cooking.

Add two more filo sheets on top in a different direction to the first sheets, brushing with butter between each layer.

Blob in the remaining creamy mix, then break in:

Add a further two filo sheets, in the same direction as the first sheets, and butter. Now lay on top of the filo:

Ensure the eggs are placed evenly over the filo pastry. Now, sprinkle over the rest of the grated cheese, spreading it evenly over the entire area. Top with the rest of the filo sheets, brushing between each layer with butter and adding a sprinkle of the sesame seeds. Fold the outside edges in and over the top and brush with butter.

7 roast pumpkin slivers or 150g grated pumpkin Blob half the creamy mixture around the pumpkin and sprinkle over half the grated cheese.

Mix together well and set aside.

Preheat the oven to 190°C.

Add two more sheets of filo to the tray (ensuring they go up the sides) and brush again with butter.

TO ASSEMBLE PIE

Now add:

1 packet (375g) filo pastry Get the filo pastry out of the packet and lay it flat (if you have to stop what you’re doing at any stage, cover the pastry with a damp tea towel so it doesn’t dry out).

Lay a sheet of filo on the large buttered roasting tray, ensuring the sheet goes up and over all four sides of the tray. Brush with butter, then lay on a second sheet and brush with butter.

7 eggs

Bake at 190°C for 30 minutes until golden brown.

Serve with fennel chips.

marinated avocado slices 200g sprouted or cooked chickpeas or 400g for vegan version Sprinkle with a third of the sesame seeds. Add two more sheets of filo and brush with butter.

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Layered wall appearance on the hemp house being built in Nothland.

HEMP HOUSE

NORTHLAND Hempcrete is a relatively new building material that is turning heads in New Zealand because of its high-performance attributes, its sustainability and low environmental footprint, and the simplicity of the system which can be installed successfully by the owner. We are building the first Hempcrete house in the Northland/ Auckland region, and only the fourth consented hempcrete home in New Zealand.

By Toby Ricketts

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H

emp ‘shiv’, which is the inner woody core of industrial hemp plants, are cut into short lengths and mixed with a binder. This is primarily made up of hydraulic lime which is combined with water. When mixed it becomes porridge like in consistency, and is ready to place into the formwork to form monolithic walls of the house, both interior and exterior.

Mixing only takes a couple of minutes (with the right hardware), and once the hempcrete has been placed, it is firm within an hour, solid within four hours, and fully cured within 6 – 14 weeks depending on temperature.

Due to the location of our build we needed to construct our house on pole foundations, and so had to rule out heavier natural building techniques, such as rammed earth, mudbrick, or even light earth. Hempcrete is less than one tenth the weight of concrete (at 330kg per cu/m) so it was feasible to construct on a supported and braced platform. This is

the first hempcrete building on poles in New Zealand, and possibly the strongest, with 146 x 250SED poles and heavy duty bracing installed. It’s a strong building!

We’ve chosen to build our house with Hempcrete as the benefits are many and varied; - Excellent insulation rating (R=5 @400mm, R=2.85 @ 200mm) - Moisture permeability – moisture can transit through the walls - Thermal mass – retaining warmth in winter, cool in summer - Fire-proof – will not burn - Rot and mould proof - Rodent proof - Amazing acoustic properties, both sound proofing and sound control - Carbon negative – actively sequesters carbon from the air in the lime hardening process

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Photos - top: Walls rising with shuttering in place.

Middle left: detail showing skeleton structure and bracing.

Bottom left: Earnest discussions towards the next steps.

Photo Rueben Taipari-Porter.

The hempcrete is formed around the studs and nogs that form the wall structure, encasing them and completely filling the cavity of standard pine framing, providing racking and bracing strength to the building. This can be modified so that the wall sits to one side or the other of the studs, so that they are still accessible. Since hempcrete doesn’t excel in compressive strength the building needs to be selfsupporting before the hempcrete is placed, so it is not relied upon as a structural member.

into conduits and secured to the studs. The wall thickness can vary between 200mm and 450mm and as you would expect - the thicker the wall, the better the insulation rating.

Since hempcrete is not brittle and is slightly flexible it is less prone to cracking, absorbs impacts better so is more robust than cement-based products, and is very well suited to earthquake prone areas as it will bend and move with the wooden framing rather than fracture.

Once placed and dried, the bare hempcrete wall resembles concrete, fibreboard, Weetabix and possibly one of those ‘picture frame sand-dune creating’ desk toys from the 1980s, all rolled into one!

We are currently halfway through placing the hempcrete in our exterior walls, and we are very happy with how it is progressing so far, but it hasn’t been a super smooth road. The main hurdles currently for people considering Hempcrete are:

Finally, it is rendered with lime render. The hempcrete wall then forms the finished outside cladding, the insulation inside the wall, the finished interior wall surfaces all-in-one, and also encloses any in-wall wiring or plumbing which has been put

Compliance with council regulations and building code – Hempcrete is an alternative solution under the building code, so will need to be shown to comply with regulations. Some research is needed for this, but we have paved the way with

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Hemp home detail, pattern in the walls as they dry out.

a document that joins it all together, showing compliance. Council rules and building codes were set up almost exclusively for a cavity wall system, so expect lots of strange, suspicious looks from inspectors, resulting in in-depth discussions about how it works! It is very unfamiliar territory for most tradies too.

Cost and transport - Currently the materials for the codemark approved building system we are using (Tradical Hempcrete) are manufactured in France

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and Holland, so need to be shipped quite a distance here to NZ. This is an extra cost to consider (as well as the import headache), but the carbon emissions during the transport are well offset by its carbon negative qualities over the life of the building, and big savings on heating in the future! This is a simple system of hemp plus lime though, so I am sure there will be local options soon. The cost is similar to a brick house of equivalent size.

Design – there are not many architects

or designers who are familiar with designing using hempcrete, but having said that - once the system is understood it doesn’t take much to add the hempcrete to a relatively standard design. Because the engineer we used wasn’t familiar with hempcrete, and there aren’t many verified tests that prove its properties under lab conditions, our house was designed and built much stronger than it probably needed to be. For example, even though hempcrete provides excellent racking/bracing strength, we

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Photos - top: North face during construction.

Bottom left and right: The walls rise…

also had to install heavy dual multi-brace straps in many walls in the building, because the hempcrete bracing strength cannot yet be relied upon due to lack of testing.

Hazardous dust – while hempcrete is nontoxic, recyclable and compostable, the dust from the bags of lime binder are quite caustic and hazardous before they are mixed with water. So investment in good quality PPE and caution are required to mix it safely.

In summary, hempcrete offers the opportunity to achieve the next level of building performance, environmental benefits and sustainability, whilst being easy and simple enough to do it yourself, or have relatively unskilled labourers place it into the walls. We have run regular free workshops to teach people about the uses of hempcrete

and have benefited from the labour donated in return. While the cost is higher than some lower performing building systems, with continued uptake the costs will reduce as the local industry scales up to meet the growing demand. With continued use, and ongoing proof of its effectiveness and durability, the regulators should make it easier to comply and actively support the use of these new, lo-fi, high performance natural building methods, so we can all benefit from healthier homes, and less environmental impact.

John Kenderdine has been experimenting with industrial hemp as a crop in the far north on a small patch of land, and was one of the lucky volunteers who got to visit Toby’s building during construction: “Unfortunately, NZ’s housing crisis has not

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just gone away so it has been interesting to visit a couple working on their own solution with hempcrete. With all the framing complete, I joined a group of people who were invited to spend a few days working with the material – mixing and placement in the formwork.

As we know, we don’t have a hemp industry in NZ as yet, so all this material has had to come in from Europe via Australia, so there are downsides in terms of transport, but until we have our own hemp industry up and running it is great to see someone getting on and doing it here. After all, without the push and desire by those dedicated to a new industry, nothing is likely to happen without it being possible to demonstrate examples.

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going to happen. Toby’s home is going to be a particularly good example which I think and hope will inspire many others to have a go. From my short experience, I found working with hempcrete easy as it was not being used structurally so no great skills were needed. The challenge for us now is to process our own industrial hemp and create our own lime binder – the materials are all here already, and as we know hemp is easily grown.

So here is what is being produced in the Far North, - the Mangamuka Republic for us all to learn from! Let us hope this will be the beginning of another peaceful revolution.”

Visit www.bcb-tradical.com and www.ozhemp.com.au for more details on the material and how to use it.

Photos - top : Hemp home interior wall detail.

Right: For Weetabix, hempcrete can be a remarkably smooth wall even before rendering.

Photo Rueben Taipari-Porter.

Far right: Every build must have a ‘selfie’- crew and woofers enjoying the moment.

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The magazine for those who dream of building their own home

Get great technical advice and regular inspiration!

Only available through direct subscription in NZ

www.theownerbuilder.com.au Sustainable Architecture Passive Solar Design Adobe - Natural Timber - Straw Solabode - Affordable Eco Homes

Mark Fielding

P: 03 546 8760 M: 021 158 5024 E: mark@ecotect.co.nz

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Photographs by the author.

E T A D UP

FROM THE NORTHLAND

HEMPCRETE HOUSE!

Working solo through COVID19

By Toby Ricketts

W

ell, it has been a rainy, rainy winter in Northland but because of our large eaves we are protected from the rain on all sides and we were able to keep working. The only problem was that Covid 19 arrived and stopped our hempcrete workshops cold. With no one able to come and help, I continued the building solo, making slow progress by mixing up around 200 liters of hemp and lime at a time and making steady headway on the exterior walls that will require roughly 50 cubic meters!

Hempcrete work can be quite meditative, especially when working in an area that is easy to access and uncomplicated. The 24

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process of opening bags, starting the mixer, adding water, carrying buckets, pouring, spreading and lightly tamping the hempcrete is easy to do whilst listening to audiobooks or podcasts, and the time really flew by.

The work is now beginning on the interior walls, which differ from the exterior walls in that they are only 200mm thick – 90mm framing and 55mm of hemp on each side.

These walls will have thermal mass and will also act as moisture sinks, regulating the temperature and humidity of the house - storing heat from the day for overnight, and absorbing the moisture we create and expelling it when humidity drops. You can

really see why they say these natural houses ‘breathe’.

One of our ethos for the house was for it to be able to breathe. The materials for each system in our house have been chosen for their moisture permeable properties: for the flooring substrate we’ve used 20mm thick Maglok dragonboard flooring, which is made from glass reinforced Magnesium Oxide – a strong, non-toxic, completely breathable material that is also fire and heat proof, plus doesn’t swell or distort when wet. Apparently, they offer a squeak-free guarantee that the floor substrate will not creak either!

Under the floor we have used Terra Lana

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wool insulation for its breathable and natural properties. The structure of sheep wool fiber is ‘hygroscopic’, meaning it absorbs & releases moisture in the form of vapour helping mitigate against the risks of damp and condensation in the home, as well as keeping the house warmer than other options available.

The other ethos of this building was to use products that could break down naturally in the environment.

While we cannot say this for all of our materials (required H5 treated pole foundations, electrical wiring and plumbing etc.) for everything for which we had a choice, we chose a biodegradable, non-toxic option.

There have been some interesting and productive conversations with the council who, while having a reputation for being very difficult when it comes to unconventional designs, have been relatively flexible to our requirements. The biggest sticking point, predictably, is water tightness. The whole concept of a breathable house is for moisture to travel through the walls dynamically.

Traditionally, houses have been

built to keep water out at all costs, because if it gets in – it will never get out, rot the timber inside, and cause mold and damp problems.

Yet, while flashings, building wrap and sealants are a great idea on conventional buildings, in a hempcrete house system they will stop the system from working, and not just reduce its effectiveness, but remove its effectiveness altogether, leaving walls that are unable to lose their moisture because of the barrier. For this reason we have had to challenge certain parts of the accepted design, mostly around the windows, where jamb flashings and head flashings would be buried inside the wall never to see any water, forming a blockage inside the wall where moisture could accumulate or be slowed. We have won some of these battles and lost some, but I wish I had been more knowledgeable and prepared at the design stage to argue the case for letting the passive hempcrete system work, without adding any barrier elements.

The exception to this is in the

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Photos - top: Internal view showing seasonal solar-friendly clerestory windows.

Bottom: Windowsill detail.

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bathroom and shower where, due to the constant drenching, it does seem to make sense to keep the water flowing on the tiles and making sure it never gets into the hempcrete. I have seen hempcrete designs in which the wet areas have a water beading agent applied to prevent water absorption, yet allowing moisture permeability, but here we stuck to a more conventional approach.

These walls will have thermal mass and will also act as moisture sinks, regulating the temperature and humidity of the house - storing heat from the day for overnight, and absorbing the moisture we create and expelling it when humidity drops.

Our cedar timber joinery recently arrived courtesy of Sailesh at Design Timber Doors & Windows in Auckland, who did a beautiful job. The installation was not complicated, but due to the 350mm thickness of the walls did require decisions as to where the 130mm thick windows would sit. I decided to mount them in the centre, giving room for a recessed sill on the interior, and protection from the elements on the exterior. The gaps around and under the windows after being packed and secured, are being packed again with hempcrete, to take up any space that could let in a draft before the window is sealed from the outside and inside.

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Now that the building is closed in, we are starting to feel warm - reaping the benefits of the hempcrete, the double glazing, the wool insulation and the location and aspect of the house which in mid-winter enjoys all day sunlight thanks to our ‘clerestory windows’ mounted high on the North face. At the height of summer there will be no direct sunlight entering the living areas after about 10am thanks to our wide eaves. This passive house design, plus the thermal mass and hygroscopic moisture sink will ensure that the internal environment will stay at a comfortable and healthy temperature and humidity throughout - with little or no inputs or energy to keep it that way.

At least, that’s the plan! We’ll let you know how it goes this summer…

Photographs by the author.

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Photos - This page: Various views of the hemp home during Toby’s solo construction period.

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KEY EVENTS IN THE

History of the development of the NZ Earth Building Standards

By Graeme North, assisted by Min Hall and Hugh Morris Photographs courtesy of Tatiana Zimina

Historic

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1971 –

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1976

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1984

C 8,000 BC People appear to start building with rammed earth and mud brick.

Somewhere around a third of the world’s population estimated to live in earth walled houses

Mid 20th Century

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1947

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1948 - 1960’s

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1951

Australian Commonwealth Experimental Building Station ‘Earth Wall Construction, 1. Pise or Rammed Earth’ written by G.F. Middleton in 1947. (This was the forerunner to Bulletin 5.)

Prof P.J. Alley builds rammed earth houses from soil cement around Canterbury.

‘Bulletin no 5 Earth-wall Construction’. George Middleton.

Experimental Building Station, Commonwealth of Australia. First edition

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Graeme North starts design/build of Yvonne Rust’s rammed earth house near Whangarei. Earth mix formulated by P.J. Alley.

‘Bulletin No 5 Earth-wall Construction’. George Middleton.

Experimental Building Station, Commonwealth of Australia, Second edition

Brian Woodward (Victoria) gives workshops on adobe near Nelson, attended by Thijs Drupsteen, Richard Walker et al ‘Bulletin No 5 Earth-wall Construction’. George Middleton.

Experimental Building Station, Commonwealth of Australia, Third edition

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1982-

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1983-4

Northland Craft Trust (NCT) established in Whangarei by Yvonne Rust. Yvonne Rust pushes Graeme North to form a united group to be formed to enable earth builders to ‘talk to Councils about Earth Building’

NCT employs Thijs Drupsteen to investigate earth building engineering, and some earth buildings built.

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M M M M M M M M

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Graeme North and Thijs Drupsteen design the first earth building to comply with the new NZ Structural Loadings Standard NZS9201 (check)

Building Act 1991 passed – performance based code encourages innovation.

Miles Allen completes ‘A Renaissance of Earth Buildings in NZ’ March Thesis, University of Auckland.

International Passive and Low Energy Conference (PLEA) at Auck University. Informal meeting of earth builders from several countries around codes/standards

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November

EBANZ Engineers conference convened by Graeme North to seek agreement on engineering criteria for earth buildings in NZ

1984-88 Richard and Bella Walker design/build adobe house in Nelson. Building permit issued in 1984. Structural design by Gary Hodder, 1984. Owner made adobe bricks 1985-6. House build 1987-88.

1987 ‘Bulletin No 5 Earth-wall Construction’. George Middleton. National Building Technology Centre, Commonwealth of Australia, Fourth edition

1988 EBANZ formed with Graeme North as chair, Thijs Drupsteen as secretary.

Ministry of Housing and Construction, Melbourne publishes ‘Adobe Guidelines’

Housing Corporation Study Grant to Graeme North to investigate earth buildings in Western Australia and USA. Jenny Christie, ‘Seismic Resistance of Traditional Earth Buildings’, ME Thesis, University of Canterbury

Northland Craft Trust publishes ‘Guidelines to Aspects of Earth Building in NZ’ by Thijs Drupsteen & Graeme North

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1990 NCT/EBANZ hosts first NZ National Conference on earth buildings. The Conference agreed that some form of code or standards for earth building needed to be put together and Miles Allen undertook this with an estimated time frame of around 6 weeks.

1990

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Engineering papers by Thijs Drupsteen, Gary Hodder, Richard Walker,

Hugh Morris, Jenny Christie. Other presenters included Graeme North, Miles Allen, and Russell Andrews.

1991 EBANZ incorporated. Graeme North inaugural Chair, with Thijs Drupsteen as Secretary.

EBANZ publishes ‘Notes on Aspects of Design of Earth Buildings in NZ’ (Thijs Drupsteen & Graeme North)

Gary Hodder publishes ‘Non-specific Design Guidelines for Earth Buildings’

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1992 Graeme North and Thijs Drupsteen work on EBANZ draft code based on NZ Masonry Standards ‘In plane tests of adobe’ by Shabani Gurumo at University of Auckland with Hugh Morris

1990’s Miles Allen undertakes major EBANZ survey of earth buildings in NZ.

Formal Standards Process Starts

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1993 Standards Association of Australia approaches SNZ about writing a joint standard for earth building.

Ian Brewer from SNZ approaches Graeme North about setting up a Joint Technical Committee (JTC) of SNZ and SAA for earth building Standards

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August 1993

Graeme North, Thijs Drupsteen and Miles Allen attend a conference in Mildura to help set up EBAA so Australia has a national earth building organisation for SAA to work with.

Inaugural EBAA Chair: Russell Andrews

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December 1993

Ian Brewer, Hugh Morris, and Thijs Drupsteen from NZ and Russell Andrews and Kevin Heathcote from Australia work out parameters for the Standards and start writing the first drafts.

Morris H. W, (1993) ‘The Strength of Engineered Earth Buildings’, Institution of Professional Engineers NZ (IPENZ) Proceedings, Hamilton, 5-9 Feb’ 1993

International Conference ‘Earth Building for the 90’s’ at Auck Uni.

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1989

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1984

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1994 In-Plane Tests of Soil Cement Rammed Earth Structural Walls’. Hugh Morris, University of Auckland

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October

First full face to face meeting of the JTC in Auckland.

Committee: Ian Brewer (SNZ), Graeme North (Chair/ EBANZ), Thijs Drupsteen (EBANZ), Miles Allen (EBANZ), Jenny Christie (Victoria University of Wellington), Hugh EARTHBUILDING MAGAZINE - www.earthbuilding.org.nz

Morris (Auckland University) , Gary Hodder (IPENZ) from NZ, Deputy Chair Russell Andrews leads the Australian team

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1995

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1996

Work continues on compilation of drafts of three complementary Standards with considerable input from both NZ and Australian practitioners.

Ditto

Richard Walker replaces Gary Hodder as IPENZ rep on the JTC.

Bob Gilkison appointed as an additional EBANZ rep

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July

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October

Full JTC Committee meeting in Melbourne but some difficulties encountered from the Australian side.

Publication of NZS 4297, 4298 and 4299

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November

1997

Official launch of the suite of Standards

Walker R, Morris H W, (1998) ‘Development of new performance based standards for earth building’, Australasian Structural Engineering Conference, Auckland, October 1998, Proceedings Volume 1, p477-484.

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February

Decision made to go ahead with NZ-only standards after various technical, legislative, and building culture differences between Australia and NZ proved too onerous to carry on as a JTC.

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June

First meeting of NZ-only Committee

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July

Drafts of NZS 4297, 4298 and 4299 released for public Comment. These were considered in November

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1999

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2000 NZIA Research Award to Graeme North for work on Standards (accepted on behalf of the whole SNZ Committee)

Morris H, Walker R, (2000) Aseismic Design and Design and Construction of Earth Buildings in New Zealand, 12th World Conference on Earthquake Engineering, Auckland, Jan-Feb 2000, Proceedings paper 2193, 8 pages.

1998 Illustrations, final technical editing, and BIA Consultation completed.

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SNZ Amendment Number 1 of NZS 4299

First Edition of the Standards are published

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Citation of Standards as Acceptable Solutions of the NZBC for B1, B2, E2 and H1.

2001 SNZ Amendment Number1 of NZS 4298 SNZ Meritorious Service Award to Graeme North (accepted on behalf of the whole SNZ Committee)

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2002

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2004-8

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2005

The Australian Earth Building Handbook HB195 by Peter Walker published by SAA

BIA fails to re-cite NZS4299 as a means of Compliance with the NZBC for E2 when E2 was hurriedly amended after the NZ leaky building saga.

Morris, H.W., North, G. ‘Earth Building Standards - The Kiwi SPRING 2020

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Approach’, Earthbuild 2005, International Earthbuilding Conference, University of Technology, Sydney, 19-21 January, 2005, p.50-50

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Morris H, (2006) ‘New Zealand performance based standards, earth construction, research and opportunities’ Getty Seismic Adobe Project Colloquium, Los Angeles, March 2006, 20 pages

MBIE Acceptable Solution E2/AS2 ‘Earth Buildings’ published after much lobbying from EBANZ.

EBANZ starts lobbying SNZ about the need to keep the three earth building Standards up to date and starts its own work towards revision of the Earth Building Standards

EBANZ funds a reconnaissance trip by Hugh Morris, Richard Walker, Thijs Drupsteen to review the performance of earth buildings after Nov 2010 Christchurch earthquakes. (Observations presented at EBANZ Annual Conference Waiheke Island Oct 2010)

Morris, H., Walker, R., & Drupsteen, T. (2010). Observations of the performance of earth buildings following the September 2010 Darfield earthquake. Bulletin of the New Zealand Society for Earthquake Engineering, 43 (4), 393-403.

Tipler, J. F., Worth, M. L., Morris, H. W., & Ma, Q. T. (2010).

Shake table testing of scaled geogrid-reinforced adobe wall models. NZSEE Annual Conference, Wellington.

Adobe Reinforced with Geogrid - Recommendations and indications of improved seismic performance

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EBANZ funds another reconnaissance trip by Hugh Morris, Richard Walker, Thijs Drupsteen, and Graeme North, to review the performance of earth buildings after February Christchurch earthquakes.

Morris, H. W., Walker, R., & Drupsteen, T. (2011). Observed effects of the 4th September 2010 Darfield Earthquake on Modern and Historic Earth Buildings. Pacific Conference on Earthquake Engineering, Auckland, N.Z. 14 April - 16 April 2011.

Morris, H. W., Walker, R., & Drupsteen, T. (2011).

Observations on the Performance of Earth Buildings following the February 2011 Christchurch Earthquake.

Earthbuilding. Magazine of the Earth Building Association of New Zealand

Morris, H. W., & Walker, R. (2011). Observations of the performance of earth buildings following the February 2011 Christchurch earthquake. Bulletin of the New Zealand Society of Earthquake Engineering, 44 (4), 358367.

2010 Suite of three NZ Earth Building Standards Referenced Documents by ASTM Standards E2392 ‘Standard Guide for Design of Earthen Wall Building Systems’.

2011

2008 May

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2006

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Morris H, (2005) ‘Seismic Research on Earth Building related to the 1998 New Zealand Earth Building Standards’, Sismoadobe 2005 - Architecture, Construction and Conservation of Earthen Buildings in Seismic Areas, Lima, Pontificia Universidad Cattolica de Peru, May 16-19, 2005, 19 pages

- Part 1. Earthbuilding, 2010 (Autumn), 22-25. Part 2.

Earthbuilding, 2010 (Winter), 10-17.

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2012

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2013-15

Hall, M. (2012) Earth and straw bale: an investigation of their performance and potential as building materials in New Zealand, M.Arch thesis, Victoria University of Wellington.

Revision drafts of Standards largely completed after many long meetings.

Most of the original Committee members still involved but Bob Gilkison was replaced by Verena Maeder. Miles Allen, and Jenny Christie no longer involved, and Peter Olorenshaw came onto the EBANZ Committee.

SNZ to be restructured and the outgoing SNZ declines to re-appoint a Technical Committee to finalise the EBANZ Drafts into Standards.

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2016 Suite of three NZ Earth Building Standards included again in the Referenced Documents in a revised ASTM

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Standards E2392 ‘Standard Guide for Design of Earthen Wall Building Systems’

After intense lobbying by EBANZ, SNZ, now a business unit within MBIE, agrees to form a new Development Committee for Earth Building Standards.

Out-of-plane adobe wall veneer tests with Verena and University of Auckland co-funded by EBANZ

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2017 EBANZ funds another reconnaissance trip by Hugh Morris, Richard Walker, Thijs Drupsteen, and Graeme North, to review the performance of earth buildings after December Kaikoura earthquakes.

(Presented at EBANZ conference in Kaikoura)

Standards Board agrees to formation of Earth Building Standards Development Committee to formally revise the three Earth Building Standards formed with Graeme North appointed Chair.

Members are: Nominating organisation

Committee member

1 2

.

Earth Building Association of P e t e New Zealand Olorenshaw

r

.

Earth Building Association of Ian Brewer New Zealand

(withdrew in 2018 to become Development Lead) 3.

Earth Building Association of Thijs Drupsteen New Zealand 4.

Building Systems Performance Rebecca Mackie branch, MBIE (withdrawn 2018) 5.

Unitec

Min Hall

6.

Structural Engineering Society Paul Jaquin New Zealand (Inc.) (Replaced by Grant Stevens 2019) 7.

New Zealand Certified Builders Alan Drayton Association 8.

Institution of Professional Richard Walker Engineers New Zealand 9.

New Zealand Institute of Graeme North Architects (chair) 10. Universities New Zealand

Hugh Morris

11. Universities New Zealand

R e g a n Potangaroa

12. Tasman District Council

Phil Beck

13. National Association of Women Verena Maeder in Construction 14. Building Officials Institute of NZ

Liz Ashwin

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Inaugural meeting of the new Standards Development

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Committee meetings and committee work continues as the drafts are refined.

2019 Materials testing continues by EBANZ on low-density mud bricks and internal mud brick veneers, as well as development work on the standards.

Drafts of NZS 4297, 4298 and 4299 released for public comment July-September.

Committee deliberates over the 400+ public comments received and finalises content from October - December.

Committee chair Graeme North awarded SNZ Certificate of Recognition for Standards work.

Revised Standards Published

MM Committee, working on EBANZ supplied drafts. After inquiry by the Standards Board, the Committee also considers wider inclusion of lower-density earthen materials, straw bale, and straw/clay or LEM sections for inclusion.

MBIE announces suspension of funding for this committee.

Drafting work continues on the Standards.

Low-density adobe walls - Out-of-plane tests with Verena Maeder and in-plane tests with Alan Drayton and University of Auckland students under Hugh Morris, and co-funded by EBANZ.

Results of out-of-plane and in-plane tests presented at EBANZ conference in Kaikoura by Hugh Morris.

Morris, H. W., Brooking, J., & Walker, R. (2017). Out-of-plane adobe wall veneer performance from a novel quasi-static and dynamic tilt test. NZSEE Conference Next Generation of Low Damage and Resilient Structures (pp. 8 pages).

Wellington.

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2019

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Dec -

Standards Approval Board agrees to the publication of

1. NZS 4297:2020 Engineering design of earth buildings,

2. NZS 4298:2020 Materials and construction for earth buildings, and

3. NZS 4299:2020 Earth buildings not requiring specific engineering design.

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2020 Graeme North, Chair of Standards Review Committee awarded MNZM in the New Year Honours for services to architecture and natural building standards February - Publication of Revised Standards NZS4297, 4298 and 4299

2021 Citation of Standards by BSP as Acceptable Solutions to the NZBC now expected 2021.

2018 BSP withdraws funding and support.

Lobbying to have funding restored continues.

OIA information request made to Government about lack of funding for development work of Earth Building Standards

Partnership agreement made between EBANZ and SNZ to allow the work to continue, funded by EBANZ

Ian Brewer resigns as EBANZ representative on the Committee in order to adopt the role of Development Lead for the standards review process.

BSP/ Rebecca Mackie withdrawn from the Committee by BSP.

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EARTHBUILDING MAGAZINE - www.earthbuilding.org.nz

The amazing plaster machine in action pumping clay slip mixture onto north side of 1st cottage.

STRAWBALE WORKSHOP Words and photos by Fraser and Faith Gould

W

e voyaged from Fiordland in the South, from Puhoi in the North and everywhere in between to converge in the beautiful Hawkes Bay for an autumn barn raising.

Well, bale raising; in eight days we built a 10m2 straw bale room with joinery installed, base plaster applied and an earthen floor laid. We attended several lectures, visited local straw bale houses and learnt pretty much everything we needed to know to embark upon our own straw bale building projects.

We were a diverse group: ambitious owner builders, high-end architects, existing earth and conventional builders, with an age range of three months to 70 years! We had come from all over the world, and as we found, the course had something to offer all of us.

The course was organised by Sol Design.

Sven Johnston travelled from Geraldine to run the workshop. Pat Mawson hosted us all on site, taught, and most importantly provided the experimental buildings on which we could learn

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which were two 10m2 rooms of the same design, one for each of his boys.

We were building a new 10m2 room for his youngest son (first cottage) but a workshop had been hosted here previously so there was already a second building on which we could practice finishing plaster coats.

Luckily for us the heavy and dirty work of foundations was completed before we arrived. The stem walls were experimental and constructed of earthbags, secured to each other with

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Sven preaching the straw bale gospel

barbed wire, and the ground with piles and waratahs. A baseplate (horizontal ladder frame) was then affixed to the foundations, waterproofed and filled with scoria for insulation. No concrete was used in the making of these fine, cunningly crafted foundations.

corners. This transfers the load of the roof evenly to the bottom plate, mitigating the uneven compression of the bales around openings in the walls which occurs with pure load-bearing straw bale construction. This method is also far more frugal with materials than traditional post and beam construction.

Day one began with lectures on natural building and straw bale construction - what is natural building? It is a very good question and there were as many answers as people which included some lively debate! We were using the buck and beam/straw bale (aka Hybrid Load Bearing) infill method. With so many handy people attending by the end of the day the bucks and beams were constructed and in place, and the rafters were up. It felt like quick progress! The Hybrid Load Bearing system incorporates vertical ladder frames primarily around openings in the building (doors, windows etc.), but also at crucial junctions such as

On our second day we were onsite learning about straw bales; I was astounded we could spend so much time talking about and analysing the qualities of various bales of straw and still feel riveted! Shape, size, and density of bales, baling machines (and their drivers), and pros and cons of different types of stalks were all discussed. While the denser the better, one can make do with pretty much any available bale. However, organic straws are apparently notorious for prickly stowaways, and chaff bales more difficult to manage than traditional small bales. Car jacks were used to compress the bales, then finally the last one was jostled into position.

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Approximately 100mm of compression per bale can be expected, but I believe that we were testing that knowledge to its limits in some places. The walls were then laced to the frame to prevent high winds blowing them out and hammered home with Pat’s homemade hammers. Angled bales for below the roof were cut with a long-barred chainsaw, a simple jig and plenty of enthusiasm. Final trimming and shaping of the walls was managed with a line strimmer, though some of the neo luddites on the team crafted other ways to achieve the same result - though none seemed quite as efficient as the weedwacker. By the end of the day all the bales were in the walls and it certainly looked as if the bulk of the labour was done. It seemed to me pretty much good enough to move in (certainly better than some flats I’ve lived in!).

On day three we learned about the ‘earth’ portion of straw bale construction. We were to apply 50mm of cob plaster to each side

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This page - top and bottom left: Squeezing final bale above compressed bales - this is how the professionals do it!

Right: Clay slip being applied with render gun.

of the walls. This was a revelation to me although I attended the 2016 International Straw Bale Conference in Methven apparently I missed this part - a straw bale house is in large part cob. In this case at least 100mm in total plus finish plasters. In addition to an earth floor this provides an amazing amount of thermal mass, which coupled with the thermal insulation properties makes for a very comfortable living environment.

Then we got muddy - the clay slip was whipped in large drums, sieved, and then mixed with sand and straw in a large drum mixer. The walls were first coated with a clay slip applied by hand or with a compressed air texture gun, which was to help key the plaster into the bales. Pat owns and operates “Matilda,” or Pat’s Amazing Plaster Machine which he uses on his professional builds.

He quipped that it can take a day to get it running, but can do a day’s work in half an hour - thanks be to the machine gods! Pat

has also been able to source dried paper pulp from a local paper mill, the fine fibres of which create a very strong bracing in the plaster, which provides tensile strength and prevents cracking. We applied the mixture by hand, by small render gun and with Pat’s Amazing Plaster Machine (Matilda.)

Sven and Pat stressed the importance of good detailing (aka where things meet) which apparently is where one can tell the master from the novice. Pat showed us how to install joinery and flashings, and most importantly, how to ensure worry free water tightness. The details are especially important in straw building as it is here that the potential for moisture to accumulate in the walls and against the plaster is mitigated.

Ever resourceful, River Rat Pat had salvaged trimmings of ultra-high-tech German building paper from previous building sites and affixed it throughout the building. The building does NOT breathe, but the building

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IS vapour permeable. Moisture is moderated by the earthen components of the system and moves through the walls ensuring condensation does not build up within the structure. The result is a warm and dry environment.

We spent the remainder of the week testing and applying finish plasters, and applying a final plaster to the existing cottage. We mixed test samples of clay plasters with various ratios of clay to sand. We played with pigments, tested different types of Japanese trowels, practiced some detailing, and used various creative techniques including Sgraffito - the plastering method where different coloured layers of plaster are applied to a wall, then cut away to create a pattern or image.

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of the plaster (which was certainly more enthusiastic than masterly!) The final afternoon was spent with us all obsessing over Tadelakt - the soaping and polishing of lime plaster which originated in Morocco, to achieve a beautiful and waterproof finish.

The week ended with a stand-alone workshop on earth floors. During the week we had made sample mixes, seven in total, each with different ratios of clay to aggregate. We waited for these to dry, then scientifically tested each one by stabbing them with a long, hard, spiky tool to establish their hardness and durability. As it happened the sample with the most aggregate was the hardest, so this was the recipe we used to pour the earth floor in the first cottage.

Photos - top left: The amazing machine - paper pulp goes in. Middle : Quick slip - plaster mixer suspended above large barrel - bucket to keep dust out of the motor and bearings. Bottom: Lime plaster served on a hawk. Right: Hand applying earth mixture on the south side of 1st cottage.

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Due to the limited space we poured another floor in Pat’s lean-to/shed so we could all get a feel for it. It was far simpler than I had expected, and having Sven and Pat walk us through testing was invaluable. Despite every natural builder I meet telling me not to skimp on testing, I’m somewhat inclined to fudge over that part, but it really was quite quick and easy. For finishing the

floor, we waited until it was ‘leather hard’ then Pat would polish with a trowel, while Sven was more inclined to apply thin slip and then wipe it off. As always personal preference, experience and the terroir are all incorporated into the Natural Builders’ intuition. A final coat of ‘boiled’ linseed oil further hardens and somewhat waterproofs the surface.

The days were steady, split into lectures, onsite learning and building. The evenings were filled with additional presentations, house tours and invaluable conversations with experienced builders and aspiring owner builders. We discussed our personal projects and shared reflections on insights into what will likely work well and where issues may arise. The conversation was stimulating and thought provoking and the lectures were well structured and professional. I found it very valuable that we spent as much time ‘off curriculum’ whilst Sven and Pat shared their experiences of trouble shooting, making the most of limited resources and developing an essential feel for the medium over long careers, together

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with accumulating a knowledge for the potential. It really would have been worth going for the hours of consultation alone.

Prior to attending the course, Fraser and I were not sure with what system we would be building our small, natural house. After this workshop we’ve decided to build with straw bales; the insulative value is wonderful, the speed with which walls go up is very alluring, learning how much earth is used in straw bale construction was the last straw (sic) and won us over. The weighty feeling of adobe and cob has always appealed to me, but with a chronic back injury moving all the mass is rather intimidating. Now we can experience the monolithic snugness of the massive walls without another slipped disc.

We highly recommend this course; it is a very well-rounded natural building seminar as all the elements in straw bale construction are readily applied to any natural building method. The knowledge, experience, resourcefulness and cunning of the hosts was extraordinary. We walked away feeling empowered, as though no problem could arise we couldn’t figure out (even if we have

to make a few phone calls), and the materials really are so forgiving. If you are thinking of embarking on any natural building project, invest the time to take this course, it was one of the greatest steps toward building our dream home.

On a personal note I’d like to share my appreciation to hosts Sven, Pat, and Rochelle, and participants alike; I attended this workshop with a three-month-old baby. For the most part I sat on the sidelines listening and asking questions, but there were plenty of offers of baby holding so I could participate, along with cups of tea, offers of the best chair, shady spots and other such pampering. I think it says a lot about the natural building community that a new mum and baby can be incorporated into such a project and I am so grateful.

This course gave us both the confidence we needed to pull the trigger and embark on our own build.

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This page - left: Applying the coat of lime plaster.

Top right: The cob plaster goes on the 1st cottage; Middle right: Applying first coat of clay plaster.

Bottom right: Willow switch is a creative horizon between the finish coats of earth and clay plaster.

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Sgraffito - Base plaster with pigment was left to dry for a day, then plain top coat applied and scraped away.

Buffing lime plaster with sponges.

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NOTE ON STRAWBALE COMPRESSION

By Pat Mawson

There is some debate about how much vertical compression is required and the best way to achieve compression in a straw bale wall. Good compression improves the structural integrity of the wall and prevents settling over time, which could lead to plaster cracking or lower thermal performance.

Broadly there are two main methods in non-load bearing straw bale structures: Bales are squeezed in under a fixed top plate (usually a structural beam), or a floating top plate is pulled down on top of bales to compress the wall.

NZS4299:2020 Appendix E (Informative section on Straw Bale in the revised Earth Building Standard) covers both methods.

In NZ standard agricultural bales from most bale presses are close to 450mm wide, 350mm high, and 900mm long. The length can vary considerably depending on the quality of the baler and operator, and the density of the crop. In my experience it is pointless trying to design the building around bale length. It is relatively easy to retie bales and adjust the length to suit as required. The amount of compression achieved will vary depending on the quality and density of the bales.

Bales can be stacked flat or on edge. The thermal performance is similar despite the 100mm difference in width because of the orientation of the straw. It is much easier to adjust bales (with a chainsaw) to fit the height of a wall if they are on edge.

Photos - opposite page, middle from left to right: Creative afternoon on the 1st cottage; Lime plaster coat - note the use of gloves; Final coat on the second cottage - very satisfying work; Detailing around window - it was stressed detail is very important, later we were shown how to make flashings.

This page from top to bottom: Final section of earth floor in 10m2 room; Tool construction - whipping up some trowels and floats for plastering; Shed Floor - Vapour barrier + homemade floats; Co-author and team mascot.

There are pros and cons with both compression methods, and both have their fan clubs.

I belong to the fixed top plate fan club! The main reason is simplicity of construction. The floating top plate assembly can quickly become complicated and once compressed creates a void at the top off the wall that must be insulated carefully and filled in. There is often a perception that it is hard to achieve compression with the fixed plate but with a little bit of ingenuity it is possible to achieve as much compression as you want. We use car jacks to squash down the wall and then hold the bales down with temporary straps while the last bale is inserted.

Maybe at a conference one day we should assemble two teams to have a compression competition! I am not sure which team would win but both walls would have far more compression than is practically required.

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The very well built, two storey strawbale passive house by Hiberna, as visited on the EBANZ AGM house tour.

Where did the story begin? If I had to draw a line in the sand, it would be the first sketches Ben and I did of a small strawbale house before we were married. It was 2007 and Ben was doing his carpentry apprenticeship and I was a sustainable building consultant, and we lived in a lovely but freezing house in Wanaka (the kind in which you need three duvets on the bed plus hats and thermals at night). Things stalled for five years or so due to travel, marriage and children, but sometime in 2012 we sat down to design the house afresh. 2012 was also the year I did the Certified Passive House Designer training.

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I

had first learned about the standard in 2004 as part of my Masters in Environmental Architecture in the UK, where at that time it was politely dismissed as some weird German idea… I then flirted with the idea of making our house Passive House, but abandoned it, thinking it would not fit with the natural, handcrafted ideal that we still hold dear.

The first design, which was consented in 2014, was one and a half storeys, strawbale downstairs and timber frame upstairs, relatively complex in form and we loved it. We sensibly (we thought) designed a large strawbale garage which we intended to live in “while we built the house.” It

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was sensible but not in the way we had intended.

Louis turned two the day we moved into that house and it served us well over the next five years. The Garage House was an exercise in frugality. It cost us less than $100,000.00 and comprised strawbale walls (still with no finish coat inside to this day) a solid earth floor and reclaimed timber windows which we retrofitted with double glazing, one by one, over several years. As it was a garage and only ‘temporary’ there was no bathroom until we added one on four years later, and in the interim we made do with a shed in the garden in which the pipes froze during winter. It was in the building of this little

STRAWBALE

PASSIVE HOUSE

By Jessica Eyres

Photos by the author

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dwelling (48 square metres downstairs and a loft office/bedroom upstairs) that we came to our senses and realised that we could never afford, neither in financial terms nor in emotional energy, the house as it was designed. Sometime around 2016 we decided metaphorically to throw those plans in the bin and start afresh with three main drivers: It should be affordable, it should be two storey (the views are much better higher up here, and I grew up in multi-level houses and have always loved stairs) and it should be Passive House. These three drivers turned out to be surprisingly compatible.

If Passive House and affordability seem to be mutually exclusive concepts - think again. The simple rectangular form was born out of both. Simple, we have come to realise, is the cornerstone of affordable.

Having worked on several complex Passive House projects since, I can say that the KISS principle – Keep it Simple, Stupid - really does apply here too.

The concept for the new house took only a couple of hours to design. The detailed design and Passive House design, as you can imagine, took a bit longer. With the fearlessness and expertise of our engineer, Paula Hugens – also a Passive House Designer - at our disposal, we set 44

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about designing what we had come to believe was the ideal marriage of low carbon construction (strawbale) and low operational energy (Passive House). At the time there had been one house in the UK that had targeted Passive House certification in a traditional strawbale house, but they had failed to achieve the stringent air permeability standard.

(There are a handful of strawbale Passive Houses around the world but at that time they all used membranes to achieve the required level of airtightness). With help and advice, we decided that it should be possible to use the internal plaster as the airtight layer. After all, plasters are frequently used as the airtight layer in masonry Passive Houses. The airtightness turned out to be a challenge, as I will explain later.

One of the reasons we had abandoned the Passive House idea was that initially Ben had wanted to make the windows himself. Slowly we let go of this idea.

The Garage House had taught us that good things take time - a lot of it - and we did not want to add three months or more to the project just for the windows.

These windows would have to be triple glazed, and airtight. Ben had the idea of consulting an old friend for advice, a joiner

Photos - Various views of the nearly completed home.

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in Germany with whom Ben had made some windows for a with this philosophy, being for the most part a monolithic client while we lived in London. Stefan also had experience material with little timber framework to break the installing Passive House standard windows (just known continuous insulation. The tricky part was the window as ‘windows’ in Germany) and he found us a ‘small’ (350 installation detail. We worked terribly hard on a set of employees) local supplier and organised the export of thermal bridge free details (I spent so long on this that in some reasonably priced timber triple glazed windows.

2017 I gave a paper on the topic at the European Strawbale We finally lodged our second set of building consent Gathering) and maybe we over did it in the end. Certainly, documentation late in 2017. Queenstown Lakes District next time we would replace the polystyrene we used to insulate the structural posts Council (QLDC) have at the openings, with a some inhouse expertise in natural product like wood strawbale building, not to The strawbale walls are fibreboard.

Interestingly, mention a relatively large perfect Passive House walls, if one ditches the curved number of strawbale houses reveals that characterise a being 15% more insulating in the district, and they were strawbale interior, achieving than the recommended R-value not averse to the idea. In a thermal bridge free detail January 2018, Ben began for a Passive House wall in a is much easier. The curve on site, while I watched cool temperate climate. The reduces the insulation at just longingly from my office in plaster is inherently airtight; the point you need it most. the Garage House. the challenge was in the The strawbale walls are Ben was keen that we junctions. A concrete slab on perfect Passive House walls, should repeat what had ground is easy to make Passive being 15% more insulating turned out to be a successful House standard, and a timber than the recommended experiment with the Garage R-value for a Passive House framed roof only needs an House: build the second level wall in a cool temperate additional insulated ‘services on the ground and crane it climate. The plaster is into place. Mostly he loved cavity’ on the inside. inherently airtight; the the intrigue this caused, but challenge was in the it also saved on scaffolding, junctions. A concrete slab and reduced the amount of on ground is easy to make Passive House standard, and time going up and down ladders and was therefore safer. a timber framed roof only needs an additional insulated Building on the ground also made it easier to protect the ‘services cavity’ on the inside. bales, so that the roof could go on quickly afterwards. By mid-2018 we had two storeys of strawbale walls, and a roof. By the end of 2018, the windows were in, and Ben was Then the fun really began. One of the aspects of Passive working on erosion testing for the finish plaster. Ben pumps House design is thermal bridge free design. Generally his plaster, and he has invested many hours perfecting a speaking, strawbale construction is very well aligned mix that is both durable and easily pumpable.

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2019 was dedicated (around other work commitments) to services, airtightness and the interior. Ben also worked with Ara - the polytechnic and training institute - in Christchurch on a moisture monitoring project; sensors which are embedded in the walls at various points around the building.

Our design philosophy has always been to keep the architecture simple and let the materials speak for themselves. However, I had difficulty limiting myself to a sensible palette for the interior as I had so many ideas stored up after thirteen years of dreaming and planning. I was lucky to have the sage advice of an interior designer from Sweden, my cousin’s partner, who helped me to rationalise my crazy ideas - as well as

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coming up with a few herself. One of the best decisions we made was the stainless-steel kitchen. Although high in embodied energy, it is zero emission and both recycled and recyclable, and highly durable.

The services were some of the last things to be completed. The house has two small 1 Kw radiators, one upstairs and one downstairs.

These are heated with a hot water heat pump which also heats the domestic hot water. We have 3kWp of Photo Voltaic (PV) panels on the roof. We installed these as soon as we could when the roof went on in Winter 2018, so we could have free power for the building process. We had long been fans of solar hot water but after much research and debate we decided on the PV-heat pump

combination for the following reasons: We have an electric car and wanted to utilise free solar power during the day to charge it.

The PV could also power the heat pump, which is on a timer and only runs during the day. The warmer ambient air temperature by day increases the heat pump’s efficiency, giving us a greater efficiency than using the PV only for water heating - an idea we had actually discounted along the way. Because we have such a low space heating demand, the heat pump could also be used to heat the radiators, which wouldn’t have worked with solar water heating unless we had sized the whole system for Winter optimisation, which is wasteful in the Summer. The extremely low primary energy demand of the house,

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coupled with the renewable generation, pushed us into the Passive House Plus category. The heat Mechanical Ventilation Heat Recovery system (MVHR) is essential for Passive Houses, not only for air quality but also for their ability to reduce space heating demand. In recovering between 80 and 90% of the heat between the outgoing and incoming air, the heat is utilised again and again. In my experience of modelling houses in our cold climate, the specification of an MVHR can reduce the space heating demand by more than 50%. Obviously, this does not preclude us from opening the windows; in fact, we’ve noticed how little the temperature drops when we’ve had the doors open for extended periods. A few weeks ago I made soap, a process which needs a lot of ventilation. I had had the windows open for a couple of hours (the temperature outside was about 9 degrees) and the temperature only dropped by 1 degree (from 23 degrees to 22). I attribute this to the high level of thermal mass we have in the building: an earth floor on concrete slab, and 40mm of lime plaster on all the strawbale walls gives us a Specific Heat Capacity of 21,000 Watt hours per Kelvin (Wh/K.) We undertook our first blower door test (the standard method for measuring airtightness) in October 2019. At this stage, the walls were plastered with only a body coat. As mentioned before, the airtightness was more challenging than in a more ‘conventional’ Passive House. The plaster was our main airtight layer: This

was joined to the other airtight elements – the slab, the roof membrane and the windows - with tapes, meshes and a product from Pro Clima called Contega PV – a product that combines mesh with tape. At the midfloor we lapped a strip of airtight membrane around the joists (we used open web joists called PosiStruts) and then connected this to the plaster on both sides. Our tester and friend, Nigel Murray of Seechange, assisted us in locating all the unseen leaks in the plaster; in a thinner layer of plaster behind an internal wall, in the plumbing penetrations and in the corners around the windows where the curved reveals meet. Our first result was around 0.9 air changes at 50 pascals, 50% higher than the PH limit of 0.6. Test 2, a few weeks later, came in at 0.65, a mere 0.01 of an air change over the limit, which is technically 0.649 thanks to Swedish rounding. Fortunately, this was revised down to 0.59 after a lengthy and thorough recalculation of the internal air volume. I must admit I was cursing all things Passive House at this point, as that tiny difference in air volume could have made the difference between a pass and fail of the goal we had worked so hard towards for so many years! A few months later Nigel came back to retest. As it had been so close, we wanted to check that it hadn’t gone up, and even hoped that it would go down now that all the finish plaster was complete. The result of this test was 0.59 air changes at 50 pascals: still a pass but no better than before, which shows that the body coat provides

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Photos - opposite page: Top left and right: The first completed project, the garage – a comfortable temporary home.

Bottom: A comfy patio This page: Bedroom interior details.

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a sufficient air barrier and the finish coat adds little, if anything, to the airtightness of the plaster.

We celebrated Christmas 2019 in the house, with no lights and no running water, but we felt it needed to be done. We wanted to thank our amazing family and friends for helping us to achieve this crazy project. Finally, on Louis’ 7th birthday, we moved in.

While I complain about how long it took to build, I need to remind myself that it took almost as long to design, and Ben managed to plaster and help build three other strawbale houses during that time!

The prolonged process has made us infinitely grateful for the final result, which despite our intimate involvement as designer, builder, PH consultant and client, still feels like magic. At the end of April and the start of the frosts, while all our neighbours are lighting their

fires, we have needed no heating as yet and the temperature has not dropped below 21.5 degrees, nor risen above 24. Holed up in lockdown, we have been able to appreciate it even more deeply.

My next job is to calculate the embodied carbon and to figure out how we can reduce it further, next time. We are working with an architect and their client in the North Island on a strawbale Passive House with a timber framed floor, which will reduce the carbon cost associated with a concrete foundation significantly.

While this house is not perfect – there were plenty of compromises along the way – it is pretty close to perfect for us and we are so proud of our ‘third child’ as we have described it in the past. It certainly was a labour of love.

Photos - top: Bathroom interior details.

Bottom: North face of the home near completion showing solar panels.

UPDATE :

JUNE

2020 We are still working on refining the heating controls. We have found that even at this time of year we don’t need the heating to come on every day (currently it is set to come on for 2 hours between 10 and 12 in the morning). When we have a week of inversion (no sun) we need slightly more than this. The temperature inside only drops about 0.5 of a degree for every 10 degrees difference between outside and inside overnight.

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Rottenomics The Story of New Zealand’s Leaky Buildings Disaster.

Written by Peter Dyer.

Book review by Graeme North

P

eter Dyer is a journalist who spent carried out.

Government. A major cause of rotting eight years researching and writing One really tough fast growing candidate – houses was a direct consequence of the this book. Many of the people he pinus radiata – stood out although variously ideological neo-liberal economic system talked to are known well to some of us, and described early on as: that swept NZ from the mid-1980’s when the period he covers involves so many of Rogernomics took hold. This book’s title of us in the building industry as we grappled ‘a tree that grows like rhubarb’ (1898), and Rottenomics is an obvious play on this. The with one of NZ’s greatest disasters. And ‘as absolutely worthless unless treated Minister of Forestry at the time stated: ‘this on top of the rotting issues, there were, in some form except for timber where no Government’s policy is to allow industry to and still are, a whole host of underlying weather reaches it. It will grow quickly almost control its own destiny without Government anywhere… and it lends itself to the soaking regulation’. As Dyer says ‘It wasn’t broke. But structural failures as well.

– in of preservatives more than any timber….’

“Anyone in the remedial industry will tell (1913 Submission to the Royal Commission they fixed it.’ you that when they tear the wall off rotting on Forestry).

In 1987 the Building Performance Guarantee buildings, they typically find other serious Scheme was axed. In 1988 the TPA was problems: structural deficiencies, fire violations, There was a fight for many years over which abolished and replaced with an industrytreatment should be adopted for pine run Timber Preservation Council. The use earthquake vulnerability and so forth”. between the boric treatment of Australian of kiln-dried timber without fungicidal This has certainly been my treatment was promoted from own experience with nearly all within the timber industry. It the remedial work I have been rotted if wet. Monolithic cladding involved with. As an aside, it “Anyone in the remedial industry became fashionable with sealants was my involvement with one of replacing flashings, which leaked. will tell you that when they tear the very early leaking buildings, The timer for the bomb to go off along with Greg O’Sullivan from the wall off rotting buildings, they was ticking.

Prendos, where I suggested retypically find other serious problems: cladding using a draining cavity The Ministry of Works (MOW) structural deficiencies, fire violations, to protect the building, let it dry gave real-world practical advice earthquake vulnerability and so forth”. out, and keep it dry. I have never to the Government as opposed to claimed being the first to think the neo-liberal faith-based advice of cavities behind cladding other coming from Treasury, so it had than brick veneer as a weathering to go. Destruction of the MOW in solution before. I believe I was, but I researchers and the British Tanalith 1988 was opposed by virtually no politician graciously let Greg take the glory as cavities promoters. Eventually this was resolved, of any stripe when it came before Parliament. were not widely welcomed when they first and the use of treated timber was rigorously Lost immediately was its enormous became common. over-seen by the Timber Preservation institutional knowledge along with a The causes of weather-tightness issues in Authority (TPA). NZ houses may have had very well-trained work force that could NZ are complex and interlinked. Some go their faults but by and large they did not effectively design and build schools, houses, back to our geographical position where we rot. The result of the TPA’s oversight was that bridges, power stations and hydro-dams. are exposed to the wind driven rain off the there was little concern about timber rotting Of course, there were continued overleaf... surrounding oceans. Some go back to the in NZ’s houses. instances of inefficiencies, as I experienced 19th century, when trials of trees to replace Then there was an ideological shift in myself, but training of its staff and a lot of the rapidly depleted native timbers were Bateman Books, 2019 ISBN 978-186953-9998-6 More information and stockists/purchase info is available at www.leaky-buildings.peterdyer.nz EARTHBUILDING MAGAZINE - www.earthbuilding.org.nz

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Research and Development was carefully and thoroughly carried out. The MOW even had a group dedicated to the writing of building and materials standards, something hard to imagine given EBANZ’s recent trials with SNZ. As I clearly recall, building control systems were uneven, annoying, and cumbersome, but there was not much wrong with the buildings.

Then we were given performance-based building controls with the 1991 Building Act. The Building Industry Authority (BIA) administered it but was toothless and

earth studio We specialise in building true rammed earth homes with clay, not cement.

- Rammed earth walls - Rammed earth floors - Japanese limestone floors - Tadelakt Moroccan waterproof plaster 027 753 6764 stefan@earthstudio.co.nz

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underfunded. There was no research around this Act’s performance-based approach. Even in 2017, even after the 2004 Building Act, that was still the case. ‘Despite nearly universal claim for performance-based regulation, the reasons supporting its use remain largely theoretical and conjectural.’ In other words, it was faith based.

In 1992 Parliament passed the repeal of Clerk of Works Act. Invaluable Clerks of Works became a dying breed. The 1993 Companies Act allowed many companies to come and go, and that allowed many fly-by-nighters to flee responsibility for shoddy work by folding the company and/or relocating overseas. Training was gutted when apprenticeship contracts were replaced with employment contracts, and organised labour was attacked.

Private building certifiers were set up to fail, and fail they did when insurance cover was unobtainable as the leaky building fiasco started to

bite.

And on and on went the perfect storm – one that Dyer reveals is estimated to doom 174,000 homes to rot, and to cost us collectively over $47 billion. These figures ignore commercial and public buildings and were only found out after the Ombudsman insisted that suppressed reports on the extent of the problem were released by MBIE. This book provides great insight and revelations about the crazy times those of us in the building industry have been grappling with ever since the start of the neo-liberal experiment in the 1980s, and the long aftermath which is still very much with us, along with its conjoined growing inequality and run-away environmental damage.

This book could have done with a good technical edit, but the message is clear enough, and should be read by everyone involved with building or building controls.

This is especially so if you have lived through a lot of this period and/or wondered how it ever could have happened.

One big technical take away message to remember: ‘All claddings leak’.

Postscript.

The great challenge we face is working out how we can help architecture change radically and quickly to cope with a new society that is being thrust upon us by a bug out of a bat, an architecture that is able to support people through collaborative local self-reliance, while also dealing decisively with climate change, environmental degradation, and inequality - all the stuff we were eagerly exploring and putting into action in the 70’s, work that was largely and very sadly swept aside by a dog-eat-dog approach.

ON THE MARKET :

WARKWORTH If you are interested in this internationally recognised eco-house on the Te Araroa Trail near Warkworth, please get in touch.

The last issue of Earthbuilding had an article about the house that Graeme North designed, built, and lives in with his wife Deniece, on nearly two acres of flat productive land near Warkworth.

You may recall it is partly a renovated early 1900’s 4-bedroom villa, now with earth plastered walls, with an additional newly built open-plan living area that is really a work of art for living in, hand crafted from natural materials, with its adjoining bedroom and ensuite.

Then there is the large barn, and various out buildings.

The property has proven itself as an absolute haven of comfort, abundance and robustness.

However time has revealed that we may not be in the right place for family connections to be readily maintained during times of difficulty.

So we are thinking about offering this unique property for sale.

Contact: graemenorth@gmail.com 50

SPRING 2020

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I would like to become part of EBANZ! FEES PAID BY DIRECT CREDIT: Email your membership details to: michael@sustainable-building.co.nz and pay the fee by direct credit into Kiwibank account 38-9007-0611251-00 (please write your last name in reference field). $50.00 for Members within New Zealand addresses or $60.00 NZD for Members with Overseas addresses

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Send your cheque to The Earth Building Association at 2152 Kaipara Coast Highway, RD4, Warkworth 0984; or contact the Advertising Manager at alan@biobuild.co.nz to arrange payment by electronic transfer. Send your ready-made advertisement in .tif .pdf or .jpg format to Ascension Creative - email: tina@ascension.net.nz.

Alternatively an advertisement can be made up for you contact tina@ascension.net.nz. There may be an additional cost for this. It will be proofed back to you for your approval before going to print.

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51

WHAT’S GOING ON & TIDBITS. . .

Compiled by The Editor. If you have events or courses you would like listed in a future Earthbuilding Magazine, please email the details to: ecoeverett@gmail.com

The Grow Room

Earth Building Association of New Zealand (EBANZ) Annual conference and AGM 30th October – 1st November Venue - Kawai Purapura, Albany, North Island Following the success of the 2018 EBANZ conference we are returning to the same venue.

Planning for the EBANZ 2020 conference and AGM is well advanced. Please see our flyer on page two and note it has become very much easier to register online. As always, the weekend will be filled with presentations, house tours and opportunities to build connections. For updates on location, presentations and house tours, check in on our website or facebook page! Please note the 2020 conference may be subject to adaptation following the Covid crisis. Planning continues apace, but please keep in touch via our website/facebook for possible changes. PLEASE BOOK EARLY.

EarthUSA Group Digital Magazine

house near Mumbai designed by architect Ranjeet Mukherjee – whom earthbuilding has previously published.

There seems to be a new ‘kid on the block’ in the form of a magazine produced by the EarthUSA Group dedicated to those interested and involved in earthen construction. The electronic version of the magazine contains a tempting variety of articles on cob, research, regulation and architecture. There are two conferences in the offing: Terra 21in early June 2021 to be held at the Santa Fe Community Convention Centre (www.terra21.org) and Earth USA 2021, September 24-26th also in Santa Fe. The magazine includes an engaging photo essay on adobe churches in New Mexico, plus two contrasting articles on cob. One highlights the materials inclusion in the International Residential Code (as an appendix) and the other discusses a European Union project that utilises cob to reduce carbon emissions. There is a lot of in-depth material in this magazine which is only the fourth issue so far. The owners don’t pay for articles but make clear they welcome submissions

The building is mostly of rammed or compressed earth and seems to contain many innovations in keeping with the architect’s philosophy.

Tiles of India The Tiles of India – a nice play on titles – has a fascinating article on a weekend retreat

52

SPRING 2020

For more information visit: www.eedtocrop.net/2020/05/ikeareleases-free-design-for-garden-spherethat-feeds-a-neighborhood/

Northmen For those of you with timber running through your veins the Northmen FB page has a lot of fascinating information on timber, preservation, tools and techniques.

For more information visit: www.earthbuilding.org.nz or www.facebook.com/earthbuilding/

For more information visit: www.earthusa.org/earthusa-news/

For those stuck in cities, IKEA’s latest piece of innovative design may have possibilities, especially if you like plywood. It is a spherical garden and it seems you can obtain the designs rather than the kit:

For more information visit: www.thetilesofindia.com/globalarchitects/architect-ranjeet-mukherjeefarmhouse-project/

The latest video demonstrates wood injuring techniques that can recreate timber that will last for centuries.

“Lost forestry techniques combined - spot barking and ring barking. Injuring growing pine trees this way, after a year when you fell the pine (during last days of waning moon before the moon’s disc is empty) - you will get a timber that is dried on stump and during this time it has extracted all the sugars from the sapwood and will become harder and harder during the time and will not be attached by fungus, blue stain or insects.”

Walipini underground greenhouse

And the techniques are mentioned by the Roman author, engineer and architect, Vitruvius, no less.

Designed more with cooler climates in mind the Walipini is a cheap and effective way of producing food year-round. Very simply it is an underground greenhouse – a big pit in the ground covered in plastic sheeting facing the sun and using the earth to store heat.

YouTube video: www.youtu.be/76nTzxNxGCs For more information visit: www.facebook.com/northmenguild/

The term is an Aymara Indian word for a place of warmth, and is certainly highly appropriate for much of our country. I presume all you need is a digger, or many spades and woofers, but the idea looks appealingly simple: For more information visit: www.seedtocrop.net/2019/02/build-a300-underground-greenhouse-for-yearround-fresh-food/

And finally – the next issue of earthbuilding will be published in early December. I would like to have as many good photographs from our house tour as participants have available, together with a couple of good reports of the 2020 conference.

EARTHBUILDING MAGAZINE - www.earthbuilding.org.nz

Check our What’s Going On page for details on photos - top to bottom: Visit Tiles of India to view more on this weekend retreat house in India.

The Grow Room spherical garden, plans available by IKEA. Cob house from EarthUSA Group Digital Magazine.