by Worldchanging local editor, Matt Waxman:
How might energy-efficiency be integrated into architectural design concerned with intriguing human experience? What opportunities and challenges do alternative materials such as straw bale provide the architect? Is straw bale construction appropriate for the earthquake-prone Bay Area?
Daniel Smith & Associates is a green architecture firm in Berkeley, California. A leader in experimental, sustainable design research and development, DSA Architects explores a range of energy-efficient, ecologically-focused building systems and natural materials, most prominently straw bale. With many projects in the Bay Area, DSA’s experience includes homes, churches, monasteries, camps, and business complexes.
I met Daniel Smith, principal of Daniel Smith & Associates, at the recent Moraga Energy Faire in Moraga, California, a community event that showcased energy-efficient solutions for homeowners. Smith came to share his experience with energy-efficient, green architecture with the small, east bay town’s residents.
In our conversation, Smith delved into his expertise in straw bale construction, his philosophy and approach to design, and discussed how green architectural systems can solve problems connected to different global contexts. Smith also described the fascinating energy-efficient architectural elements of his recently completed Presentation Retreat Center, a LEED Gold-rated straw bale building in Los Gatos.
Matthew Waxman: Could you please introduce yourself and tell me about your approach to architecture in the Bay Area and your philosophy involving architecture, materials, and the building and design process?
Daniel Smith: I’m Dan Smith, and we have a firm in Berkeley. Over the last ten years we have become more and more involved in green architecture. I think getting involved in alternative materials is of interest in itself as it keeps me excited.
For example, straw bale is evolving as a building system that works in Earthquake Country. It is a challenge and has a lot of advantages, but it is three-times as heavy as a stud wall; this means you would have to have three-times more bracing. But if it’s well connected – stronger mesh and plasters – straw bale performs as well or better than a plywood shear wall because it can actually absorb a lot of the force conductively without cracking and breaking traumatically -- it absorbs the energy.
Straw bale is a thick walled, high mass system that works in Earthquake Country much better than adobe or rammed earth, or even cobb (which I like very much). Cobb does have a lot of tensile strength in its straw but it’s very heavy. Straw bale gives you a good mix of insulation and thermal mass on the inside to keep the temperatures even. It’s a much better fit for passive solar in this area, especially in a high seismic area.
When compared to regular stud walls, straw bale has a totally different feeling. When you’re inside a straw bale building, for one it’s radiant and its surfaces are either a warm or a cooler because it doesn’t cool down and heat up as fast as stud walls. Straw bale is also quiet and feels secure mainly because it is much tougher -- it’s like a stone building and you feel that. They’ve actually done some tests in Texas for hurricane loading by shooting guns or firing two-by-fours into the straw bale -- it will stop a 22-caliber bullet. It won’t stop a high caliber, but it’s a lot better in this sense than stud wall. This is not an explicit reason to do straw bale, but it’s part of the feeling of being more secure in the thickness.
MW: So as a material it not only works structurally-well in the Bay Area, but it can also create an interesting experience architecturally?
DS: It is interesting. I’ve found that churches and groups that like to have a space for congregation really appreciate straw bale because it’s more of a container of sound, as well as thermal. And I think it may evoke thick-walled, medieval buildings, stone buildings, or earthen construction -- it does have that character to it.
MW: Could you build a modern day cathedral with straw bale? A very large structure?
DS: Yes, because we’re typically not doing straw bale in a load-bearing manner, which is the traditional way it’s done in Nebraska or the south-west. We’re using a light frame, wood frame typically. But in the Presentation Retreat Center building in Los Gatos the high walls are 25-feet high. So here we have a very light steel frame going up there [to the top]. The bales are really spanning between these framing members so theoretically you could just keep on going higher. That this is 25 feet high and a large space -- it is certainly feasible to do larger. There are questions with exterior weather protection because you still don’t want to have a high-rise unprotected, and you’d have to detail it differently.
MW: In the Bay Area, were there straw bale structures built before the 1989 earthquake that survived and demonstrated the durability?
DS: No, because there were no straw bale buildings at that time. I think there was one in Davis but I think it’s from the 1990s. There was a revival in the early ‘90s, mid ‘90s, started mainly in the south-west, and they went back and looked at Nebraska where there was a round of straw bale buildings in the teens and ‘20s, and a number of those buildings are still existing, and that’s what gave the comfort level to try it. Because there is not much to see on them and they’re 80 years old, you can pull some of the straw out and it looks just like regular straw, it doesn’t look degraded. And those were very sloppily-build. It’s a very dry climate so it worked well.
Straw bale was then started in Tucson and Santa Fe, and it was introduced here [San Francisco Bay Area] around ‘95. Now California has a livelier straw bale community than Arizona or New Mexico. What we’re doing here is typically more expensive and definitely more structurally-together because of the earthquakes. California is more of a building-code-intensive environment.
MW: When you were talking about the structural durability, it was making me think of Todao Ando’s buildings that survived the Kobe earthquake and Shigeru Ban’s paper disaster-response structures built afterwards, and their flexibility for disaster. Do you think straw bale could be a material to use in a case of disaster?
DS: For sure, in fact we’ve got a couple friends working in Pakistan’s earthquake zone. And they’re going back for the second year and they’ve come up with a straw bale minimal house, and very inexpensive to build. It’s ideal to replace what Pakistan has, which is un-reinforced masonry which is a death trap because it doesn’t have the strength to hold itself together, and when it comes down, it comes down on your head. So these are little straw bale buildings using bamboo pins tying it together and earth plaster. No mesh, no concrete in the skins, and they’re building them for a couple thousand dollars in materials costs. The buildings are small, four or five hundred square feet. And that’s about half the cost of the approved concrete buildings that Pakistan is trying to build and are generally too expensive. So it’s a good match because not only can you make it earthquake safe enough but it’s thermally far more efficient that what they’ve got.
We’ve helped with some straw bale housing in Mongolia and now it has spread to China. Kelly Lerner, who has worked in my office as an office assistant and has done a marvelous job, has started working with an aid agency to introduce straw bale construction into parts of China that have been devastated by earthquakes. And there they are replacing brick buildings and then the roof structures have earth on them, and so the UN has gotten involved in supporting it. And there has been quite a bit of straw bale in that area and, like in Mongolia, it can get to 40 below and they haven’t really been building with any insulation, and this gets them through with maybe one-fifth less of the energy needed to heat their houses.
MW: This then makes a great alternative to an HVAC system.
DS: Right, all they have to have are these foil or wood stoves – I’m talking about more out there, not right in the city. But it’s a nice balance because you can relate to contexts where the low-cost of straw bale makes sense, and they really need it because it’s very cold and don’t necessary have the wood. We’re really unique having all this access to wood construction, and it’s not really sustainable in the long-run to be using wood the way we are. Most of the world doesn’t have it, they have to build with earth or other materials, and straw is a rapidly-renewable, abundantly available material, so it makes sense to use it.
It’s very nice to have these projects in other contexts to balance really nice upscale houses in Santa Cruz and Sonoma. Straw bale adapts very well to the upscale Marin, Sonoma houses that are sometimes Mediterranean style, thick wall, sometimes they look like adobe, and the straw bale fits right in. So it’s ironic that the straw bale world here is more upscale while in Arizona it is a lively, counter-cultural, without permit, out in the country, and buildings done very cheaply; and in other countries it's seen as a low-cost housing alternative.
When you mentioned the buildings in Pakistan as being a death trap, it made me think of in squatter cities where the construction is very poorly put together and the electrical infrastructure, for example, is ad-hoc, and in any disaster houses might collapse or fall onto each other. Maybe straw bale would be a solution in those areas?
Well it is, but it’s not for everywhere. Hot, humid climates are much more of a challenge for straw bale. It’s a cellulous material and it can rot. If it gets too wet or too hot – that’s what mold likes. And that’s why they don’t build wood houses in a lot of those areas. But, that said, there is an awful lot of the world that is cold and dry or even temperate, and where it does make a lot of sense. We’ve done it in Tennessee where it’s hot and sometimes humid. But there it gets more critical that you have really good overhangs, so you don’t get a huge amount of rain directly on the wall. And if it gets that way its probably better to use highly permeable plaster, such as an earth plaster. And luckily in Tennessee they don’t have the seismic loading and they don’t need the very strong plasters that we often use here and that tend to have more cement.
In Pakistan the concrete buildings tend to do better because they are reinforced. But it’s really the stone buildings and the ones that are un-reinforced that tend to be death traps. And that’s why un-reinforced masonry has basically been outlawed in the Bay Area. All the old brick buildings -- well not outlawed -- but they have to been reinforced. And you have to go through them and strengthen them, and that’s a huge cost. But there’s a lot of un-reinforced masonry in the rest of the world.
MW: Could you tell me about a current project you recently completed?
DS: This Presentation Retreat Center; it’s a dining hall and welcoming center at this wonderful retreat center down in Los Gatos, and they have facilities for 200 people that go there for retreats and events. This is a LEED certified Gold-rated building where we have photovoltaics integrated into the roofing, and the other half of the building is an earth-sheltered green roof. There is also solar thermal heating for the hot water for dishwashing.
There are straw bale walls that are integrated with a passive cooling system taking the air from outside and through a basement area to cool it down and then to automate night-time cooling, and so it pushes out through the building through the high two-story windows. We’ve been able to do that and get away from using air conditioning.
We have an evaporative cooler that uses far less energy than compressive cooling. We were only able to do that because of the thermal performance of the straw bale walls and because of all the thermal mass inside the insulation allowing the passive heating and cooling to work and lower the loads.
So the purpose of this building – they see it as educational – and they’ve got a display up of all the green features of the building. It’s really a nice place to visit in that regard. The ceilings are all recycled newspaper cellulose and on the exposed surfaces and then back inside on the insulation. And it’s got cotton blue-jeans insulation for cotton insulation. The wood in the trusses and framing is FSC certified, which means it's certified that it's been sustainabily grown. Typically that’s a bit more expensive but it’s verifying that the wood has not been cut down in a wanton manner.
It also has very highly-efficient lighting. We have daylighting consciously and low-energy fluorescent lights throughout. And so that’s a challenge too, to make sure that our fluorescent lighting is doing a good job and looks pleasant. And we’re doing that now in houses. The state requires it in bathrooms and kitchens and we’re trying to use the compact-fluorescents throughout the houses and in ways that people aren’t offended by the fluorescent look. In fact the compact-fluorescents have gotten much better in regard to their light rendering.
MW: Could you please elaborate on the solar thermal heating/ outdoor light-shading elements?
DS: They are the solar thermal collectors; solar heating hot water. And it makes sense in this project because it’s a dining hall for 200 people, so it’s a lot of dishwashing, hot water demands. These are vacuated tube collectors; that’s a four-inch glass cylinder where the air has been vacuated – it’s a vacuum – and inside is a copper pipe attached to a flat copper plate that then can be rotated to face the sun. These things can be placed in a panel of six or more tubes, and they can go in flat and just have the interior baffles facing the roof.
What I like about them is that, for one, they are a lot more efficient than a standard flat-plate collector. High efficency, for what it is. Putting it in for horizontal sun-shade also doesn’t have the clunky, solar-panel on the roof, sticking up in the air look, but it’s integrated into the sun-screen function which I would have to use wood panels or metal to do the same. So we’re actually shading the building with 180 degree water.
It’s doing this nice conjunction of problems, and doing it in a way that you can see it. It’s architecturally expressed and I like the fact that people can walk around and see how it’s happening, and also you get to see the light tinkling through this thing -- an elegant light fixture. That’s what I like to do best about green features, to make them full of delight. Like what Vitruvius said, architecture is firmness, commodity, and delight. It’s nice to get that in there. Because green and energy efficiency can sometimes be all about efficiency and it is not always delightful. It’s a nice conjunction.
MW: In regard to light as a material -- and in relationship to the straw bale material used for the walls -- is there a way you can play with the light coming through the straw bale? Can you break it up or are there minimum widths? Can you fragment the structures and have punctures and holes?
DS: You can but you pay for it more than in regular construction. But on the other hand you can play with the light much more effectively because you have at least eighteen inches on the inside of a wall that you can angle so that it can take the light that’s bouncing from a window, and instead of it being a high glare light to wall – which is black – it is a transition gradient, and this could even curve. It is a much softer light transition to your eye as you look at it. It also allows another surface to bounce the light. In terms to how the light enters the building it is a lot more interesting, I think.
But in terms of construction we like to make bigger, simpler openings on the south, where you want the light, rather than lots of little openings. Even though we have done some of those – for instance here are some little puncture openings on a western wall [points to a separate project], which is where it makes sense to have small openings, that’s a lot of extra detailing for each of those openings. And in terms of bales, you can cut them and re-tie them, and it can be done and we do it all the time in houses, but it’s a bit of a procedure. It’s nice to stay with openings that are on module or are bigger, simpler openings.
MW: When I was in college at UC Santa Cruz, a student in the school’s Education for Sustainable Living Program instructed a class where students built a straw bale shed. What I thought was fascinating about this was that it was both a learning experience and a community building type activity bringing people together. What do you think about straw bale having the ability to connect and structure community and places?
DS: A bale raising. I think in every job that we’ve done there has been a bale raising event. Sometimes it is symbolic in that there are contractors and everything else, but it is a way for people to come in and actually take part. The barn raising and bale raising is an old tradition and is inherently a community-type thing. It’s a terrific way to install community spirit – like with our Shorebird Nature Center in Berkeley. Here we probably had thirty people there for the bale raising and plaster raising, and I think it knit the building into the community much better. We had one project where there was actually a wedding during the bale raising.
What’s nice about it is there are less power tools and hammering involved, so it’s much more accessible to kids. And women really like to get into it; there’s a lot of knitting, stitching that mesh from side to side. There is a range of things for people to do. It is tough with regular construction to find comfortable roles for people to play.
And it gives people the sense they can build their own house. Like Legos stacking up, they think “I could do that!” It gets a lot of people into it and then they have to deal with everything else, because everything else is still a huge job. But it gets people to build their own houses, which is a part of American life that has been lost to a large degree and was a can-do American spirit. In the 19th Century people were coming up with different ways to make things and build things.
I find a lot of interest in Silicon Valley, for example, with a lot of people into computers and electronics, they love this kind of grounding, because it’s literally grounding. And straw bale is literally heavier; you’re not going to pick it up and move it easily. And that’s another fundamentally different thing about this from standard American construction; it’s not lightweight and you can’t build it in a factory and ship it out. It’s going to stay there.
MW: What is your vision for the future of the bay area, architecture, and the world, and how do you see yourself fitting into the vision? With the different things you’ve been doing that make up your career, how does all this create this vision?
DS: It evolves. I think what’s interesting on an architectural level is the warping of what people think is beautiful in architecture is getting changed with green design and the environmental. For example, I recently bought a Prius. Three years ago I couldn’t stand it. I thought it looked too self-conscious and funny-looking. It took me a year to appreciate it, and I think that is what’s happening with green architecture. It has had a lot of funky PV panels up there and crunchy-granola image to it, and it’s evolving and becoming much more architecturally mainstream.
But it’s also changing things. Glasswalls on all four sides is now starting to look ugly to me. It colors what you think looks good. And that, on one level, is very interesting. I’d say in terms of where I am, from what I’ve picked up with my experiences with straw bale construction and plastering, trying to use natural fibers, lowered embodied energy materials such as earthen plasters, plasters in general less energy intensive concrete and more fly ash, everything is going to fit in a lot of ways.
And straw bale is rather crude. I mean, it works nicely but I don’t necessarily think it’s the future. But straw made into straw plywood or composite blocks or panels – there are lots of different ways to do it. Plus the idea that everything doesn’t have to be industrialized. There are a lot of people in the world who are happy to do work to build houses, like the favelas and slums you mentioned, that if they could get the material to build cheap enough, would love to build a better, stronger house. So that’s an interesting challenge. How do you cut energy use by a factor of ten, for example, or cut emissions down? We just don’t think about building and figuring out what’s the embodied energy of fiberglass insulation. It’s going to be interesting. I think all the architects now are starting to get interested in it. And the evolution is going to speed up.
MW: Thank you!
images of Presentation Retreat Center by DSA Architects
Small correction -
Great article. Thanks for getting and keeping the green word out to folks.
I did have a minor correction regarding one of the people mentioned in the article. The article mentioned that architect Kelly Lerner (One World Design Architecture - www.one-world-design.com) worked as an office assistant at Daniel Smith and Assoc.
Actually, Kelly was hired as an architectural intern by Dan's firm after she graduated from University of Oregon with her Masters in Architecture. While with Dan Smith and Assoc., Kelly collaborated on a number of design projects including Santa Sabina Hermitage, the Shorebird Nature Center and Frog Hollow Farm Housing and a number of others.
Kelly left Dan's firm to start her own very successful firm which focuses on sustainable, green design and specializes in strawbale construction.
She has a new book out titled "Natural Remodeling For The Not-So-Green House", which has been selected as a finalist for the Nautilus Book Award.
(The Nautilus Book Award is a unique award that is given for distinguished literary contributions. It recognizes authors and books that contribute to our society’s awareness and well-being, and which embrace spiritual and ecological values such as compassion, sustainability, simplicity, and global peace.)
Hi Deborah, thanks for the clarification and links to Kelly Lerner's work!
I wonder what sort of green materials would be recommended in a hot and humid country like Singapore? Ideally, it would be sustainable, insulating, strong, light and affordable too. :)
Anyone care to share their ideas?
How do i get hold of more information on how to use straw bale or similar materials for low cost shelters. I would appreciate it if we could in touch with someone who is interested in helping build low cost shelters from indigenous materials specifically in the Philippines.
@Mathew Waxman: I would look into earthship for Singapore. It's a rammed-earth thermal mass structure similar to straw-bale buildings, but for materials they use tires and dirt, both very cheap and very accessible. The most hi-tech piece of construction equipment you'll need is a backhoe. They also passively heat and cool, recycle their own waste on site, collect their own water, use solar electricity, and eventually, will hopefully grow their own food (that's still in development). The basic design can be customized for any climate and latitude to maximize water collection, comfortable temperature, and solar use.
I know nothing about Singapore's building regulations, but you might have trouble getting approvals to build an earthship in an urban or suburban area. Right now people are primarily building them in rural areas, but they have the potential to be "stacked" along a slope to make communities and cities. I hope this helps!
@Hun Bun - Oops, my apologies, Hun Bun and Michael! The above comment should read @Hun Bun. I thought the "posted by" was above the comment, not below. Sorry for the mix-up!