 The need to protect forests is why I became involved in straw bale construction. As a society, our demand for wood outpaces our forest ability to provide for it. We're now going farther and farther afield to meet that demand, we're into the forest in Canada and Siberia. As a designer working in the home building industry for the last 20 years, I've seen a consistent trend of declining lumber quality and increasing prices over that time. This is clearly unsustainable. We need to do it some other way. And the answer may be right in our own backyards. California's rice growers are producing enough straw every year to build the walls of half the state's new housing stock. Rice straw doesn't readily decompose. It has a high silica content which makes it very resistant to decay. So the farmers have been burning it in the fields for years. This has created a huge pollution problem, so much so that the state has mandated a phase out of the burning over the next few years. There's a very pressing need to find somewhere to put all that straw. So we say put it in the walls of your house. Everybody wins. We solve a serious waste problem. We clean up the valley air. We give people tremendously energy efficient homes and we save some stands of region forest. And the really magical thing is that people love straw bale homes. I've got a lot of reasons for being interested in straw bale construction. Perhaps one of my early problems I developed as a farmer in a rancher was exactly what was I going to do with the leftover straw from my wheat crop. And I had to either burn it or plow it in and neither one of them was a very good option. I've also been very concerned about what's going to happen to the future of my grandchildren. Are they going to have the opportunities that I've had? And can we better use our resources? Are we wasting things that we should be utilizing better? Nature doesn't destroy anything. It recycles everything. And yet our construction industry is aimed at build, destroy, and haul to the landfill. And the use of materials like straw bale will allow us to recycle and provide a better future for our grandchildren. Neil Hancock and Jenny Blaker wanted to build a tool shed and a workspace behind their home in Cotati, California. They decided to build it using straw bale. Straw bale was an idea of using resources that were available as a waste resource, something that could be recycled and be inherently more part of nature. So we decided that we would look into it and we visited a number of straw bale buildings that people are doing here in and around Sonoma County. So we started a discussion with our local planning department and they were very favorable. They'd heard of straw bales. They basically said providing you can fit in with a legal system. Basically have a structural engineer design the building. Then they'd have no problems with it. And we had an architect who just did a basic design for the building, which is 24 feet by 16 feet. So it's basically a one room building, very simple size and shape. Then because we're officially in the flood plain, we had to have the building raised 20 inches above grade. And an engineer had the planning department needed to see either an architect or an engineer stamp on the plans. When Neil and Jenny came in with their project in August, I helped them find out what they needed to provide me and the way of plans, what they would need in planning as far as setbacks requirements before the Clan and Commission, if there were any design review issues, which there weren't in their case. It's one of the first projects in Katadi that is straw bale construction. As an inspector, we're allowed to accept alternative building methods. And I felt that this structure was in full compliance all the way up to the final inspection. But for their own benefit, I felt that they should have an engineer or an architect look at the plans and stamp them. As a building code official, the use of some of the alternative materials is presented new challenge to me. Typically, I think most building officials I know that I am are accustomed to utilizing materials that have certification attached to them or come with research reports or have approval systems that we're comfortable in working with, have long histories. But when we approach some of the alternative construction materials, such as straw bale construction, it doesn't come with those normal approved processes. But if you will think about it for a moment, all of the things that we're comfortable in using, such as brick, concrete, steel, wood, have gone through a process of trial and error over the years. And the use of straw bale construction is really not much different than that. And I found that if I, early on, if I just loosened up a little bit in the way I approach these things and use my imagination, talk to some people that have worked with it before and then allow somebody to do a project, an experimental basis, a small scale to elevate my comfort with how this works and what it does that it improved my ability to work with these types of new types of materials. But it's going to be a learning process for the building official and you have to be willing to spend a little time and become acquainted with some new materials. So we found an architect, Paul Harris, who did the basic design for the building and an engineer, Bruce King, who had done a lot of work with straw bale building before, who worked on the details of the building and the foundations and exactly what was needed structurally. As an inspector, there are a couple of pretty basic things for you to be aware of when you're looking at a straw bale project. Possibly the first thing that a lot of people think of is fire and as it turns out that's the least of your concerns. Fire on a straw bale project is a very big concern during construction. When the bales are going up and partial sized bales are being cut and made, straws flying around, you tend to end up with anywhere from a few to 12 inches of loose straw lying around on the site and it's obviously a big fire hazard. It's common sense, although we've had a lot of fires on straw bale projects suggesting that perhaps not everybody has enough common sense, to simply have extra precautions during that period of construction. Hoses, fire extinguishers, whatever, and being very careful with brazing or soldering or welding or other things that might start a fire. It's a very big fire hazard on the site when the bales are going up. But once they are up and especially once the plaster is on them, straw bale walls have surprised us in that they are extremely fire-resistive. We have done laboratory testing in New Mexico and demonstrated that a straw bale wall, well, I don't think it was quantified or unsanctified yet, but it appears to be at least a two-hour firewall, possibly better even than that. And I use the analogy, it's like throwing a phone book into a fireplace. It doesn't burn, it just chars around the outside, just like a very big chunk of wood tends to do. A straw bale doesn't tend to burn, it chars on the outside, and that's about it. As long as it's kept intact, especially if it's held in a wall and it's plastered on both sides, it's very, very hard to burn. Personally, living here in California where we have wildfires in the Chaparral, they get very hot and are very destructive. I'd far rather be in a straw bale house, a straw bale building, than I would in a wood frame house, which is going to go up much, much, much faster. So straw, or rather fire, is just not a big issue with straw bale other than during construction. Once we've got the permit, then we started going through the how to put it together and the foundations. And the foundations were a lot of fun because we're in a flood plain and we needed to raise up the floor 20 inches off the ground. Or off the grade, as a sort of the technical jargon. Typically, you're going to have more foundation for a straw bale wall. And just like you do with wood, you need to get it up off the ground so that water won't attack it at the base, and so that water can get out if it ever gets into the wall. On top of the foundations, there's 4x4 with peak gravel, and then the bales rest on top of that. We have evolved a number of details that are really basically common sense to make sure water doesn't get in, and then in the event that it does, you get a roof leak, or a window blows out, or something happens and water does get into a straw bale wall, you give it an avenue of escape. There was vertical rebar also at regular intervals through the foundations, and the straw bales were kind of impaled onto the rebar to keep the bales in place. Then there's the walls. The straw bale walls. It's only the walls, but it affects everything else. It affects the design from an engineering point of view, and of course it affects the construction. During construction, it's going to affect how the foundation is built, what kind of framing may go around it, how the roof sits on top of it. It affects finishes and fixtures, how the cabinets get attached, how finishes get attached, how electrical goes in, how plumbing goes in. While Neil and Jenny's building here, we didn't have any plumbing because it was a storage shed. I think they're going to use it for an office as well, and we ran power in, but typically you wouldn't run a plumbing line in a straw bale wall if you could avoid it because lines will sweat. The moisture can cause a problem. If you have to have a plumbing line, you run it through the wall and typically use a sleeve so the sweat will be contained within a plastic sleeve. We had people arrive, and they were like, I'm going to use a plastic sleeve. We had people arrive for the barn raising or the wall raising with great excitement, and we all got stuck into it and had a number of experienced people, which was really great. Some people already done two or three of the buildings already, so we were able to put them on different parts of the wall. Got the rebar cutters going, which was one of the most difficult parts, having these rebars that would get cut, and sort of the shock of cutting them, and how to cut them at an angle so that it would be easy to actually hammer them in. Then we had a bale raising day, which was a fantastic experience. It was a real community building event. When we had friends and neighbours and straw bale enthusiasts, people we'd never met before who heard about it, who came along to help. All our neighbours chipped in. We must have had about 25 people through the day working at putting the bales up, and the bales went up fast. Most of the work was done in a day, and then some of the more detailed work was done the following days. Straw bales went up, and on the walls, initially they went on the first layer of rebar that had come through from the foundations that was holding the bottom straw bales into the foundations. And then we went up with four layers of bales, and after that, for the fourth, fifth and sixth layers, we hammered in 55 inches of rebar, and that was with a four-pound hammer. That was a lot of work. That was also very, very hard. From a design point of view, it makes a big difference as with any other kind of building material, whether you're in an earthquake area or not. If you're not, i.e., seismic zone 2B or less in the parlance of the code, a one-story, even a two-story straw bale building is inherently pretty stable, at least all the ones that have been built so far. We hammered in the rebars, and we were knocking them in, and then on each corner, we had two sets of staples, U-shaped staples, 15 inches wide by about six inches deep, and they held the wall. Now, one of the parts that was really quite interesting was monitoring which parts of the wall got the staples, because we were in the raising the wall, and some people were keen on getting the bales up, and they just wheeled the bales, and then they'd go up on the wall. We had to have a wall monitor for checking out the staples actually went in at the corners, and that we hammered in the pieces of rebar, because it wasn't a popular thing to do to hammer in this rebar. I don't know. We didn't get too many rambos coming, I guess. So the walls went up, then we have the windows and doors to put in. At every place, whether it was going to be a window or a door, a carpenter had prepared a wooden, a buck, like a frame to just keep the hole open, keep the space, and then the bucks were secured by putting a wooden dowel through into the straw. The windows were put in place later on by the builders. Another thing that a lot of people are doing now is pre-compressing the straw bale walls before putting the plaster on. The concrete had black plastic pipes put down through the foundations at regular intervals to take a polyester strap, which went down through the foundations, up around the walls, over the roof plate, down the other side, to be tightened to pre-compress the walls once the bales were up. Very, very nicely designed, and it was very, very simple to put together. The tightening of the straps is another part of the story, and that was quite a lot of fun. The roof, no big deal. We're putting very ordinary roofs on top of straw bale buildings, regardless of what kind of wall construction it is. The roof framing is virtually the same as it is for any other kind of building. And so far as I have ever seen, the roofing or the roof framing isn't really affected by the presence of straw bale walls below. So there's pretty much nothing to think about there, except that it's generally a good idea to have a big overhang to help keep the water off of the straw bale wall. There are two basic kinds of straw bale structures. Load bearing, where you put the weight of the roof, or even a floor above, on the straw bale wall, or post and beam, or non-load bearing. In which you don't. You have a framework of concrete, or concrete block, or steel, or more typically wood that surrounds the straw bale, or rather is the framework that all the loads go on. And then the straw bale wall is simply an infill panel. It has to be able to hold itself up and out of plain loading, but that's really about it. That's what most people are doing. They tend to be easier to get a permit for. And in some ways, they're easier to build. In some ways, they're not as easy to build. It may be that as things evolve and we learn more about the material, that load bearing straw bale will become the most common means. My own personal suspicion with what I know is that that will be the case, and it'll be a very common means of construction that everybody will become more comfortable with putting the weight of at least a roof on a straw bale wall, if not a floor on a roof. But as an engineer and as a builder and as an owner, the thing, a very important thing to understand about a straw bale structure, whether it's post and beam or load bearing, is that it is very much like, the best metaphor I can think of is a hard-boiled egg. Somewhat stiff and soft on the inside and can even carry load on the straw, but once the plaster is on there, that is what carries the load, the wind load, the earthquake load, the vertical load from above. It goes on the skins because they're very stiff. You have to understand the structure that way, and it's really a hybrid. The straw then just serves as it were, permanent insulating formwork for the plaster, and it also braces the plaster to some extent. We haven't been able to measure, we haven't measured it yet, we can measure it, we just haven't done so yet. But it's a hybrid structure, very much like reinforced concrete, very much like all sorts of sandwich panel structures that we're familiar with. Then, the next stage was to do the stucco on the walls, and we heard about a team called Helping Hands, Gary and Shahoma Boudreau from Ashland in Oregon. Who travel up and down the west coast, showing people how to put stucco on straw bale buildings. The first part of the stuccoing is to have the wire netting up against the straw, and the wire netting has two purposes. One is structural, and the other is to actually hold the stucco in place. By having the stucco against the straw, you're making us a very strong combination. Around the windows and the door, we use metal laugh as well. It's called blood laugh because it's really sharp, and it goes around the curves of the windows and doors, stuffed up with loose straw in between. So the building has beautiful curves around, especially the inside of the doors and windows. So we've got the wire mesh covering the whole of the outside of the building and the inside, and it's really starting to look like a building, and stuff. At this stage inside the building, it was very, very nice and quiet, and the straw bale was just lovely to be in it. But we needed the coating. We needed to have the stuccoing, and we started on the stucco coating one morning, and up it went. So we were stuccoing, we basically put up the layer, and there's a lot of arm movement for that, a lot of muscles, and a lot of learning how to pick up this sort of mud, the cement, that was going to get very, very hard, but spread it up on the wall, and basically get it out. It seals it against moisture, and against any possibility of pests creeping in. Although apparently pests aren't really a problem, because there is no nutrition in the straw, so there's nothing in the straw that they'd actually want to eat. At the end of it, it gets scratched, because there's at least two layers to be able to guarantee, or to really try and keep the water out. And the first coat is called the scratch coat, because you scratch it at the end of it, so that the second coat can actually go up on it. The stucco is left to dry for at least two weeks, and then a second coating is applied, which can be coloured. So we've chosen a kind of red, brown, adobe colour. We actually waited four weeks because of waiting for the stucco team to come back. And then they came back, and now we're putting on this lovely red coat on the top that looks very, very reddish. What else can I say? And sort of got lots of character to it. It really hides the grey cement very nicely. At that point, any kind of little individual artistic creative things can be done with stones pressed into the stucco, or leaf patterns, or whatever you want. And then I think once that's done, we'll just have a few little details to do like painting the windows and getting the door up to scratch. We used recycled windows and doors, so they need painting and finishing off. And I think that'll be it. So among the things that we have learned to date in 1998 as to clear do's and don'ts with straw bale construction, some of them are obvious, or at least common sense, with regard to controlling moisture, keeping it out. Some of them are not so obvious, and in particular one is very paramount that you do not put paper on the walls. Despite our inclination to put paper, a moisture barrier, a vapor barrier, both on walls that we stucco, you do not want to do that with straw bale, both because you want to let the wall breathe. If any moisture ever does come in, it needs to be able to get out. You don't want to trap any moisture that might accidentally get in. And just as importantly, you want the structure to behave as an entire assembly. You don't want to separate the plaster from the straw. They work together structurally. They seem to work together for moisture as well, and that they become an assembly that though it can't admit some moisture, will let it right back out again. We've looked at this anecdotally. We've torn apart some buildings. We're studying this. We'd like to know a lot of things about how moisture behaves in straw bale walls. But again, the overwhelming evidence from all anybody can tell in a lot of different climates, and basically every basic kind of climate, is that you don't want to put paper on the walls. With the possible exception that you put paper on the top to keep water off of the roof or from a roof leak from going into the wall, and you maybe put some paper on the bottom, one or two courses on the outside where there is rain splash or snow drift, and a lot of water will attack the wall. Hey, maybe it's a good idea there. But other than that, let the wall breathe. It's an organic beast and it needs to breathe. People love straw bale houses. They harken back to the thick walls of Europe or the southwestern adobes here in this country. But unlike cold stone or cold earth, straw bales are warm in the winter time and cool in the summertime. Because they're modular, straw bales fit into almost any building system. You can have a cottage or a villa, a complex plan or a very, very simple plan. The only thing that's unique about them is the thickness of the walls. And that in and of itself is beautiful. Instead of a window just being a hole and a wall, a window becomes an actual space, a sitting space or a place for plants, books, you name it, you can put it there. And if you bevel back the sides, you have beautiful reflection curves around your windows. Straw bales, you can carve into them, you can create nichos, you can create bookshelves, you can create seating benches, anything you like. The really exciting thing about working with straw bale construction is that it's a completely winning proposition. We save wood, people get warm, thermally efficient houses, and they have a tremendous spirit in them. I'm very interested in helping to develop resources that are renewable and that more easily blend in with nature's method of recycling. And I think this is an excellent opportunity for us to develop and to utilize a material that we're otherwise wasting. And I'm very supportive of the move toward the use of alternative materials. The job finished up nicely. They're happy with it, the city's happy with it. And so I'm looking forward to possibly more structures of the same. That's what the California Straw Building Association is all about. We're just trying to move this process along, make it even easier for everyone to build with straw bales here in California. We're a group of professionals, designers, engineers, owner builders, anybody with an interest in straw bale construction. We're educating ourselves about straw bale construction and sharing that information with our membership. We're conducting research and testing and we're also trying to provide information to building officials, people who are out there dealing with straw bale construction on a day to day basis. If you'd like more information about straw bale construction, you can contact us at 805-546-4274 or you can write us at 115 Angelita Avenue, Pacifica, California 94044.