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Mountains and Domes: A B&B in Thailand built using rice husks

By Asia, Design, Earth Buildings, Issue 70, Roofs No Comments

This article first appeared in The Owner Builder 192 December 2015/ January 2016. www.theownerbuilder.com.au

By Maggi McKerron

Ten years ago I fell in love with a mountain. Mt Chiang Dao rises 2173 metres out of the forests of northern Thailand, its jungle covered peaks dressed in swirls of clouds. I leased a piece of land on a small hill facing the mountain. Under half a hectare, the land slopes down to a small rural Thai village under the mountain, clustered around the nationally famous Chiang Dao Cave.

Planning a B&B

I was approaching upper middle age and realised I needed to make some sort of plan for older age when my life might possibly slow down a little. This piece of land would be perfect for a B&B!

I did not have the money to develop the land, so I took off for the UK to make some. Although I am British, I was born in India and have always lived in Asia. Going to the UK to work was a challenging experience, as I had to learn to live in a western culture for the first time, at the age of 56.

mckerron-_24

Earthbag B&B

While in the UK I took the opportunity to study natural building, beginning with an inspirational earthbag building workshop taught by Paulina Wojciechowska, author of the first book on earthbag building. Making a dome out of earthbags sold me on domes and round dwellings. I was determined to build round domes back in Thailand!

Rice husks

But using earth as the building material did not sit right with me. I am mildly asthmatic and need dry air and did not relish the thought of being enclosed in an earthen dome during six months of monsoon rains. I thought about rice husks. This is a product that no one wants. It takes ages to break down if added to compost, and is difficult to burn. It is also a desiccant, which means that it will draw moisture out of the atmosphere. Perfect!

After seven years in the UK I finally had enough money to return to Thailand. At least I hoped it was enough. There was no way I could calculate the costs of the buildings in any detail, as I did not really know how I was going to build my rice husk domes. I couldn’t find any information on the internet: no plans available, no books on building with rice husks. I worked out a financial guesstimate, which I finally reached in savings, and I bought a one way ticket back to Thailand.

My beautiful land was covered in towering brush and it was not until a team of machete wielding villagers cleared it that I discovered how steeply it sloped. What a challenge this was going to be!

I should mention here that where I was building, out in the scarcely populated countryside, planning permission, although preferred by the local council, was not an issue. In towns and cities I would have had to submit plans. My local council signed off the building after it was finished.

Beginning the build

Ready to begin my adventure, I posted on social media that I would welcome anyone who would like to help with the project, and people turned up. I hired some local day labourers from the village. We found the flattest area, at the top of the property, and one of the first steps was to prepare for a concrete base. I had been warned by locals that the termites were ferocious and there really was no alternative to concrete.

We marked out a circle 5.5 metres in diameter with some bamboo stakes. Then we got some tubing and filled it with water, and tried to find a level. No one believed what the water in the tubes was telling us, so I went and bought a spirit level. This confirmed the water’s message; there was still a big slope, even though compared with the rest of the land it looked practically flat. Leveling the area was our first task.

My very rough plan showed a concrete cap on the dome, as this was all I could think of to keep out the monsoon rain, so our next task was putting up six concrete posts to carry the weight of the concrete cap. Then the base of sub soil and stones went in, pounded flat
by enthusiastic volunteers, a trellis of bamboo for strengthening, a sheet of plastic as a damp proof membrane to stop moisture leaching upward, some sand and a final topping of concrete.

The dome

Now I needed to seriously consider the dome. I could not for the life of me work out how to construct it. Unlike earthbags, which are load bearing and could support a concrete cap, I was working with lightweight, not at all solid, bags of rice husks. I spent ages in hardware stores, second-hand wood shops and looking through books. I asked various local builders, but one after the other they shook their heads, mystified with the ideas of the crazy foreign lady.

At one point I decided to forget the dome and just build a hexagonal roof using the steel for conventional roof frames. One of the volunteers said: ‘But Maggi, your dream is a dome. You must follow your dream.’ So I thought again.

Weaving the bamboo

Weaving the bamboo

Bird cage

I found reinforced steel rods, rebar, bendable and long. I could buy quite thick pieces and long enough to go from one side of a dome to the other. First a piece of rebar was bent into a circle to go around the building, sitting on the top of the concrete posts. Then up went the rebar making the dome shape and we wired it onto the posts and horizontal rebar. Using different thicknesses of rebar and adding bamboo we made a dome shaped trellis.

The bamboo for the trellis in the dome came from bamboo poles we harvested from the land. These we cut and prepared and wove as needed. We used the same trellis idea for the walls, and our bags of rice husks would be attached to this frame. The whole thing looked like a giant bird cage!

The windows and doors were added as we built the bamboo trellis. This was complicated as the walls were going to be quite thick, so windows and doors needed frames to sit in. We learned as we went along. At no point in the building did we use any electrical tools – there was no electricity!

Rice husk walls

Filling in the walls came next. I found a place that sold second-hand polypropylene bags and had bought several hundred. Then I found a rice mill that agreed to fill the bags for me with their waste husks, 200 a week. These we had been collecting in preparation.

The first layer of bags was filled with gravel to guard against water and moisture damaging the walls, with a layer of sand on top of that, then the bags filled with rice husks. We experimented with different types of string, and different knots and found the method that worked best. They went up quickly and easily in a couple of days, and soon we were at the level where the curve of the dome began.

The bags were too big. They would be too unwieldy and heavy to attach. We had to empty them, refill them with less rice husks, then tie them up in the shape of a sausage. Our sausages were quite complicated to put up as we were attaching them to the inside of the dome to continue the inside line of the walls.

The dome looked wonderful! The next step was to put on the concrete cap. We used plastic sheet covered with chicken wire and put the concrete on top. We made deep overhangs to protect the walls.

mckerron-_15

Finished dome

Mud render

The last step was the mud on the walls. It took a while to perfect our recipe as putting plaster on bags of rice husks is not the same as putting it onto earthbags or straw bales. The bags were not solid, so plaster had to be built up slowly in several layers until it was firm and strong. Then a final layer of lime plaster, followed by some decorations, and our dome was finished!

The big lesson I learned was never to put a concrete cap on a dome in the kind of climate found in Thailand. It cracked, and cracked again! But because the rice husks dry out so easily it has not caused any lasting problems. The second lesson was to attach the bags to the outside of the dome trellis. Much easier!

Three years have gone by since the beginning of the adventure. I have three domes and five roundhouses with thatched roofs. All the buildings with their thick walls of rice husks covered with earthen plaster are cool in summer and warm in winter. I have a beautiful home, made from three of the five metre roundhouses, joined by thatched walkways. My B&B is up and running. And every day and all day I can see my mountain. My dream has come true.

Maggi will be running a roundhouse building workshop in November 2017.  See website for details: www.chiangdao-roundhouses.com

Links & resources

Maggie’s Blog

Sharing her adventures of living – and building – in Chiang Dao, northern Thailand.

maggimck.wordpress.com

Chiang Dao Roundhouses

Set on the side of a hill overlooking the spectacular Mt Chiang Dao, offering rice husk workshops and B&B accommodation.

www.chiangdao-roundhouses.com

The Growth of Hemp Lime as a Natural Building Method

By Hemp-Lime, Issue 63, Walls One Comment

by Tom Woolley

Ed Note:  More in-depth information on hemp lime will be in Issue #64 due out in July.

Hemp Lime wall immediately after shuttering has been removed

Hemp lime wall immediately after shuttering has been removed

When Rachel Bevan and I did the research that led to the publication of Hemp Lime Construction in 2006-7 (IHS BRE Press ISBN 978-1-84806-033-3) we had a fairly good idea of the location of every building using hempcrete in the UK and Ireland. Seven years or so later it is impossible to keep track of the use of this remarkable composite building material as it has become commonplace in the UK. This is good news because it is evidence of the widespread acceptance of this excellent sustainable way of building. However once such an innovative form of construction becomes so widely used there is also a risk of careless and poorly supervised construction, detailing and specification if it is used by people who  expect it to behave like ‘conventional’ materials.  Fortunately a new book : The Hempcrete Book: Designing and building with hemp lime will soon be available . By Alex Sparrow and Will Stanwix it will be published by Green Books (ISBN: 978 0 85784 120 9 )*** and will set out guidance for best practice in building construction for hemp lime

Hemp Lime construction is a method for creating a natural “concrete” which provides a solid wall system either cast around or within a timber frame structure. The composite uses small pieces of hemp shiv or hurd, which is the chopped up woody core of the plant and then mixed with water and a special lime binder mix. It is incredibly strong almost as soon as it is cast into formwork or sprayed onto permanent shuttering. The formwork can be removed almost straight away or left on for 12 hours before casting the next lift. It then takes a couple of weeks to dry out and longer to gain its full strength. Sceptics often ask, “why use hemp, and why not use wood chips or straw?” people often say (there is an inbuilt prejudice because of its relationship to Marijuana). The best way to convince such people is for a practical demonstration and it is possible to see straight away the strength of the composite. Hemp is much tougher and can cope with moisture better than other cellulose materials.

Prefabricated Hemp Lime Wall

Prefabricated Hemp Lime Wall

The resulting composite provides a solid wall with superb air tightness capabilities and very good insulation. Its density of 300-400 kg/m3 is strong but light and contains air pockets in the tubular hemp plant structure giving a “u”value of about 0.2 for a 300mm thick wall. (Lambda 0.06/mK). In practice the thermal performance of hemp lime, or hempcrete as it is often called, is enhanced by its thermal mass and thus the actual performance of a building is often much better than predicted by the abstract thermal resistance figures. Hemp Lime also has the benefit of being full breathable and hygroscopic so that humidity is controlled. Because of this it has been adopted by major commercial food and wine storage companies* to insulate storage warehouses as the walls provide a stable temperature and indoor climate without the need for heating, cooling or air conditioning. Hemp lime insulating walls have also been used by the British Musuem for storing special artifacts.

Hundreds of social housing schemes and one-off private houses have been built using hemp lime and it has also been used in major public and educational buildings, 5 or 6 storeys high.

Completed apartment building in Letchworth, England built with hempcrete

Completed apartment building in Letchworth, England built with hempcrete

Hemp lime is versatile so it can be used as an infill in multi-storey construction, in floors and roofs, as a renovating or insulating plaster and as an external render for straw bale buildings and other eco forms of construction.

Supply of materials has not been fully sorted out yet. Hemp shiv or hurd is readily available but not always in the right place so it has to be transported from processing factories where the hemp fibre is stripped off the plant. The hemp fibre is a valuable crop with a thousand uses, so the shiv used for building is almost just a by-product. Making or sourcing the lime binder is also tricky. There are a range of proprietary products available such as Tradical, Batichanvre and recently Ciment Prompt [French]. These are not always available from local suppliers of building materials. It is possible to mix up your own binder but it is essential to use the right materials with careful quality control. The binder is largely lime based, mainly hydraulic lime but some hydrated lime and or cement is also added. There have been a few “cowboys” who have been supplying hemp and lime materials that are not fit for purpose and this has led to a few building failures. Their main mistake has been to use cheap hydrated lime, often too much water and hemp fibre as well as shiv. One company even says it is more ecological to use the whole of the hemp plant even though this invariably leads to a soggy mess. We are working hard to establish proper standards. Sadly the internet gives people partial information about how to build with hemp lime and makes them into overnight experts.

Social Housing Scheme in Northern Ireland built with hempcrete (Photo Oaklee Housing Association)

Social Housing Scheme in Northern Ireland built with hempcrete (Photo Oaklee Housing Association)

In some ways hempcrete is easy to use and is even tolerant of misuse, within limits, but this means that there are many dangers and possible pitfalls. On the other hand, once you become aware of its advantages it is hard to find another way of building walls, (and possibly floors and roofs), that can meet so many of today’s demands of sustainable, healthy and energy efficient construction so successfully. As pressure builds to meet ever more strenuous energy efficiency targets, many weird and wonderful building techniques and materials have appeared in the market.  While some mainstream architects and clients have embraced hemp lime quite quickly the construction industry is still largely wedded to synthetic petrochemical based methods of construction that contain many risks both to the health of building occupants and the planet. Valuable and non-renewable fossil fuel resources produce significant CO2 emissions even though ironically they are being used to reduce such emissions! Recent research shows that many so-called low or zero energy buildings consume more energy in producing the materials and construction (embodied energy) than is saved in the lifetime of the building. These synthetic quick fix approaches to building also present serious fire hazards, emit toxic chemicals. Leading to poor indoor air quality and pollute the planet when disposed of in landfill. Despite this the devotees of “Passiv Hause” in the UK tend to use synthetic materials, though there are a handful of Passiv Haus projects in Ireland that have been built with hemp.

Hempcrete is not only a low embodied energy material, it locks up CO2 in the building fabric. While land is required to grow it, hemp is also a valuable food crop and is used as an intercrop between wheat and other cereals. Those who are fixated on the ‘techy’ quick fix synthetic solutions, disparage hempcrete as being too slow to construct and dry out and not giving good enough thermal performance.  However even the most deeply prejudiced, once they actually experience hempcrete, are soon won over. Despite the obstacles to using hempcrete, its rise has been rapid as it almost sells itself as a solution to producing environmentally friendly buildings. Hemp lime is widely used in France and recent workshops in Holland, Denmark, Sweden, Poland etc. have led to projects in many of these countries.

Hempcrete wall following removal of shuttering showing timber frame

Hempcrete wall following removal of shuttering showing timber frame

In many ways hempcrete is a touchstone to the adoption of a sustainable and environmentally responsible approach to building and renovation because it provides a key to solving so many problems that other materials and buildings systems cannot cope with. As hemp can be grown in so many parts of the world, providing it is not too arid, it can be a solution to insulating buildings in poorer developing regions as well as the gas guzzling western countries. Hemp provides food, oil, clothing, paper and many other products as well as building insulation and weather protection. Hempcrete in conjunction with timber, as long as it is used carefully, should last much longer than many of the petrochemical based greenwash materials being used today.

Designing and building with hempcrete is a real demonstration of a total commitment to ‘saving the planet” and protecting the health and wellbeing of building occupants. It’s an easy commitment to make because hempcrete is affordable, great fun to build with and ticks all the boxes that envirocrats can come up with.

*Companies like The Wine Warehouse, Marks and Spencers etc.

Tom Woolley was Professor of Architecture at Queens University Belfast from 1991 to 2007 and now works for Rachel Bevan Architects. He created the first strawbale building, in Crossgar County Down 1997, to receive full planning and building regulations approval in the UK  and has gone on to be one of the pioneers of hemp lime construction. He has written a chapter about hemp construction of the new edition of The Art of Natural Building (Chelsea Green) to be published later this year. He will be running a workshop on hemp lime construction at the Endeavour Centre** in Ontario November 1 and 2, 2014 and lecturing at Ryerson University in Toronto on October 30th 2014.

Tom is part of a group of architects and builders that are establishing a hemp lime association in the UK.  He is also on the European board of Natureplus, a certification system for ecological materials. www.natureplus.org

An example of a hemp lime building that can be rented as a holiday cottage can be found at http://www.irishcottagesdown.com/cottages/downpatrick/hempcottage.htm.  There are links to some technical details and a video showing the construction process.

 ** Contact Chris Magwood for details

***The Hempcrete Book: Designing and building with hemp lime
by William Stanwix and Alex Sparrow 
ISBN: 9780857842244 Full colour Hardback 272 Pages Publication October 2014 
www.facebook.com/HempcreteBook 
Pre-order The Hempcrete Book through www.greenbooks.co.uk and all good high-street and online retailers 
To qualify for 20% off the cover price, join the pre-publication mailing list at http://eepurl.com/OMZoT

 

Book Review: Making Better Buildings

By Book Reviews, Issue 62 No Comments

Reviewed by Jeff Ruppert

Image-front-cover_coverbookpageMaking Better Buildings: A Comparative Guide to Sustainable Construction for Homeowners and Contractors by Chris Magwood will be released this Spring and promises to be one of the most valuable tools for the designer and builder who wants to understand how their choices of systems rank in terms of environmental impact, cost and acceptability.  No other compilation gives such an in-depth review of the most widely used natural building techniques.  Not only will you find the tried and true methods of straw bale and rammed earth construction, you will find alternatives you never knew existed.

Being a guide, this is not a how-to manual.  It does not have pictures showing how to build alternatives to concrete foundations, for example.  What this book does is ensures you are not missing something, and if you are you will easily find it and be able to compare it quickly to what you think is the best choice.  The information on each system is objective and easily referenced.  What is so impressive about this book is the list of systems it covers:

  • Foundations
  • Walls and Insulation
  • Floor and roof structure
  • Sheathing and cladding materials
  • Roof sheathing
  • Flooring
  • Surface finishing materials
  • Windows
  • Mechanical systems
  • Water systems
  • Wastewater systems
  • Heating and cooling systems
  • Electrical generation

As a designer of natural buildings I found the tables used for comparison very easy to glance through.  I was able to discern the most valuable information quickly once I became familiar with the format.  Comparing choices is easy and finding the characteristics that may keep one system or another from fitting into a project simple.  The format forces you to think about each system using the same set of parameters, such as code acceptance, embodied energy, waste generated, costs, durability, etc.

But let’s not mince words when talking about green building.  This book is clear – the current mainstream methods of making buildings sucks from an environmental point of view and no matter how certified they are, they just aren’t that green.  The systems reviewed in this book address the most fundamental issues facing our society and the construction trades.  Systems such as steel and concrete construction are not included due to the simple fact that both materials cause huge harm to our environment.  There is no need to waste paper (or bandwidth) on the higher end of impact and societal costs when you are focusing on real solutions.  If you are reading this book it means you are serious about considering real alternatives in this day and age of high impact buildings and “greenwashing.”

Chris Magwood continues to bring us fresh ideas and perspectives with this publication.  We recommend it not only to the professional designer and builder, but also to owners who are serious about making better choices on their next project.

Making Better Buildings will be available in March for $39.95 USD and CAD from New Society Publishers.  It is approximately 460 pages and will be available in both paperback and as an eBook.  

Paperback ISBN: 978-0-86571-706-0; eISBN: 978-1-55092-515-9

Disclaimer: Chris Magwood has appeared as guest editor in past issues and submits articles regularly to The Last Straw.

 

Adsorption (More Building Science)

By Bales, Building Science, Issue 62, Straw Bale Construction, Technical No Comments

Building-ScienceBy Chris Magwood

An important concept to understand when considering moisture and building materials is adsorption. Moisture in vapor form infiltrates any and all materials. The surface of most materials will offer individual water molecules an electrically charged attraction, and the water molecules will “stick” to all available surfaces. The makeup of plaster and of straw bales offers a vast amount of surface area for this adsorption. Plasters are full of micro-pores and straw has great deal of available surface area as well as micro-pores in the hollow stems. Together, these materials allow a surprisingly large amount of moisture to safely adsorb onto/into the materials without the water molecules accumulating in sufficient layers to become drops of liquid water. Bales and plaster can hold a remarkable amount of moisture in adsorbed form. “For a 8 pcf (pounds per cubic foot) bale, more than 1 pound of water (approx. 1/12 gallon or 0.46 liters) in vapour form can safely be stored per square foot of wall area” according to John Straube in Building Science Digest BSD-112. This explains why the walls can perform so well as “vapor open” or “vapor permeable” systems.

Better Quality, Ecological Correctness through Sustainable Design – TLS #59

By Bales, Community, Design, Fire, Uncategorized, Water No Comments

This article appeared in TLS #59.

by Ken Haggard and Polly Cooper – California, USA

Adopted from an article that appeared in Home Power Magazine.

Straw-bale cottage during construction.

Straw-bale cottage during construction.

Like many other architectural firms in California, San Luis Obispo Sustainability Group architects had been designing building that utilized passive solar for many years. Like many other architectural firms around the country, and around the world, in recent years we found ourselves shifting our design work to “sustainability,” an extension of passive solar design concepts.

The definition of sustainability we use in our work is to use resources that meet our needs but do not compromise the ability of future generations to meet their needs. As our firm and the work we do evolved, our practice has evolved to encompass broader issues including life cycle impacts of materials, miniaturization of infrastructure, health issues in buildings, permaculture and landscape regeneration.

By 1994, we had developed a comfortable working environment, consisting of a mix-used passive solar complex that included an office, shops and a residence on an old trout farm adjacent to the Los Padres National Forest, 12 minutes north of the city of San Luis Obispo. Little did we imagine that we would endure the trauma of losing nearly everything we owned or that this tragedy would afford an opportunity to redevelop our complex based on our new knowledge of sustainability. In August 1994, the 41 Wild Fire that burned 40,000 acres/16,200 hectares in our area destroyed our entire complex, and forced us into applying these broader principles of sustainable design for ourselves. Once we got over the initial shock of losing an extensive library, slide collection, office and home, it became more and more obvious what an opportunity our natural fire-oriented local ecology offered us – we could start from scratch and build sustainably, without the problem associated with retrofitting existing structures.

One of the first things we realized was that the fire had left us with a large inventory of building material. (We had several strawbale benches on the site before the fire. They turned out to be more fire resistant than most of the stucco-, tile- and metal-clad buildings in the canyon.) It had killed most of the mature trees (except for 2/4 of the fire-adapted oaks), and these trees were now available to use as lumber. We would never have dared touch them while they were alive. In addition, the massive opening-up of the landscape afforded by the fire allowed us to examine our aging infrastructure. We realized it could be redone in a much more sustainable way. Landscape regeneration became an everyday reality, not some theoretical subject. We suddenly could do things that we had only talked about, but never had the time to do – like getting off the electrical grid.

cottage2

Completed straw-bale cottage.

Right after the fire, it was necessary to develop a base of operations – a place to store tools, plan from and live in. We attempted to combine this need with several others, such as providing future retreat for guests and visitors, as well as a demonstration workshop for our senior sustainable design architecture class at Cal Poly State University. The result was a 500 sf/46m2 cottage that we built on a slab that was left from a shed we had removed long ago. his was one of the few slabs in the canyon not destroyed by the re, because it supported no flammable building at the time. For the structure of this building, we used fire-damaged telephone polls with a truss joist frame. We built the walls from rice straw bales laid on edge, which provide good insulation. In addition, the stucco finish provides interior distributed thermal mass. For the ceiling, we used wheat straw bales laid flat between TJI rafters, which also provide good insulation. The roof is corrugated steel sheet, and includes a 4-ft.x 8-ft/1.2mx3.4m skylight with skylid (movable insulation) unit. Our electrical power came from a Pelton wheel (a microhydro system) on the creek connected to storage batteries.

The construction of this building used healthier building materials that produced less waste. The unused straw was used for erosion control on the site. The building also gets much of its heat from the sun, and uses waste as a resource. In addition, the structure served as a prototype to test details that we planned to use in the larger buildings.

Sustainable Materials

In sustainable design circles, there is a lot of talk about the advantages of using regional materials. As practitioners, we always had nagging doubts about how much of this is truth and how much is idealized theory. Once construction of the guest cottage was underway, we turned our attention to testing this theory. There were several stands of mature trees on the site, especially in the creek areas. The oaks, Sargent cypress and several pine species were native. The Douglas fir and redwoods were not, although their natural range on the coast extends to just 10 miles/48 km north of the site. They were planted 33 years ago when the trout pods were developed. After the fire, all the redwoods put our new growth immediately, and three-quarters of the oaks sprouted from at least part of the remaining trunks. The other trees were killed. We now had an opportunity to do what passive solar applications do – use resources directly on the site rather than importing them from far away and exporting the impact elsewhere.

We felt obligated to mill the dead trees into lumber for reconstruction. We hired sawyers to do this during the fall of 1994, suing a wood Miser portable mill. Both we and the sawyers were amazed at the quantity and quality of wood produced in this relatively small area. We harvested 22,000 board feet of lumber, enough for construction of the other buildings with enough left over to be a storage, rain and sun protection chore. The economics of this also created the unusual condition of using straw-bale construction in conjunction with heavy timber construction, as it was more economical to mill big pieces rather than small ones.

The result of this experience was very interesting. The wood we obtained cost about the same as it would have from a lumberyard, but the quality was much higher. In addition, all phases of the life cycle of this material – source, transport, processing, use and source regeneration – happened on the site. Waste could not be exported elsewhere. It became a resource used for erosion control and organic matter for the regenerative process.

It became obvious to us that although the first costs of both milling our own lumber and buying it from a lumber yard were about the same, the long-range environmental costs of milling our own was much less. These costs are not often accounted for in our present economic system.

The Studio/Office

interiorThe next step was construction of the studio and office, completed at the end of March 1995. Because of the function of this building, we placed great emphasis on natural lighting in addition to the passive solar design. The studio/office is also off-grid, powered by photovoltaic (PV) panels over the library/research area, with a Pelton wheel on the adjacent creek for use as backup in the winter when the water is high. (Two streams fed by the nearby mountain range flow through the property.) The studio/office is heavy timber-frame construction with straw-bale infill.

The south side of the office is configured to allow maximum sun penetration in the winter and begins to shade itself in early April. During the summer months, it is totally in shade, picking up sun again in late September. Parts of this facade are view windows, part unvented 12-in./30cm Trombe walls that also act as shear walls, and part 9-inch-thick/23cm water tanks below the south-facing window on each end that act as indirect gain passive heaters. The Trombe walls and water tanks are painted with a selective surface paint on the sun-facing side.

The wiggly light shelf on this south facade serves two purposes: providing summer shading of the windows and low water tanks and throwing light deeper into the building in winter. This office is also designed for maximum night ventilation. Summer breezes generally flow from southwest to northeast, so the air moves through the long dimension of the office. These breezes, coupled with the large amount of distributed thermal mass in the building, keeps the interior temperatures below 79oF/26oC, even when daytime summer temperatures are quite hot, occasionally reaching 110oF/43oC.

The Residence

The two-story residence of the complex was completed in October 1997. We used construction techniques similar to those in the office, except that the heavy timber structure is placed 6 in./15cm inside the straw-bale walls. This configuration allowed us to expose the beautiful timber frame and create a continuous two-story straw-bale wall without interruption of the north side. The curves of this wall were very easy to achieve with straw bales without any added expense. This is the best arrangement of the timber structure and bale walls we’ve found to date. There are remarkably few cracks in this wall. The contrast to the stuccoed wood shear walls on the east side is very telling.

The residence uses interior 8-in./20cm concrete block walls as shear walls, thermal mass and decorate “gates.” Besides south-facing glass, skylights provide direct gain, with skylids as thermal control. We’ve found that this system offers more flexibility in the fall and spring than fixed overhangs.  The El Nino weather pattern sometimes produces a very unusual cool late spring, which we cannot respond to in the studio with its fixed overhangs. The skylight/skylid arrangement in the residence did allow us to respond to these unusual climatic conditions. The residence is also off-grid, powered by the PV system and Pelton wheel backup that provides electricity to the rest of the complex.

Landscape Regeneration

exteriorOne of the unexpected joys of this whole ordeal has been to experience the rapid regeneration of the landscape following the fire. Fire is such an integral part of the native California landscape that everything is set up for it. The first spring was dominated by delicate fire poppies, which only appear in newly burned areas.   In this case the seeds had been waiting 60 years for their chance – it had been that long since this area last burned. The next year was dominated by morning glories, which spread all over the armature of the burned branches of earlier plants. The third year was the year of low herbal plants – sages, bush poppies, soap roots and others.  In the fourth year, we found the Ceonothus (wild lilac) dominating. The regeneration of oak and cypress trees then began to be much more noticeable.

The best wood for reconstruction turned out to be the Sargent cypress, used for the structure and trim. Alder was the best for cabinets. The cypress trees regenerated naturally because they were a fire species whose seeds are stimulated when they are burned. When the office was done, to commemorate the wonderful alder cabinet it contains, we planted several times the number of alders in the creek than were there before the fire.

Better Quality, Ecological Correctness

We’ve found that the application of our design theories to our own situation has helped convince clients and others that sustainability is more than just another theory. It is a way of achieving better value while simultaneously having far less impact on our planet. In fact, once we get beyond the fears of scarcity that haunt our industrial culture, we will see that these two values – better quality and ecological correctness – are interrelated.

Ken Haggard and Polly Cooper are principals with the San Luis Obispo Sustainability Group, 16550 Oracle Oak, Santa Margarita, California 93453; 805.438.4452, fax 805.428.4680 <[email protected]> www.slosustainability.com

Ed.Note – An article about the curved wall straw-bale workshop building (not pictured in this issue) at Ken and Polly’s complex will be included in TLS#60/Details, Details, Details. It’s amazing in its design and structure.