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WHAT I THINK I MIGHT HAVE SAID IN NEBRASKA
by Chris Magwood, Camel's Back Straw Bale Construction, Canada Attending the 2nd Nebraska Straw bale Conference was one of the highlights of my involvement with straw bale construction. Being from The Far North, I have been maintaining "observer status" with the large and vibrant American straw bale community, watching and learning from a distance. The chance to mingle and talk with many of my straw bale heroes and to spend some quality time immersed in the thinking and scheming side of natural building sent me home excited and reinvigorated. And, I'm still full of that energy. Despite having given Joyce some outline of what I was planning to say during my presentation at the conference, I must admit that I really did not know what I was going to say until I stood up on Saturday night and opened my mouth. With so many excellent and experienced speakers going before me, I did not want to fall into repeating what had already been said. So, as I listened to others, I took a few notes about what I might be able to add (or subtract) from the goings-on. I started my presentation with an overview of our three most interesting projects of this season. The first was a very large loadbearing home (3,200 square feet, with a 75-foot section of straight wall!) which definitely pushed our parameters of what we thought could be done with loadbearing structures. The building went up quickly, easily and came in under budget. All the things we love about the simplicity and effectiveness of loadbearing designs, stretched to extra-large size! The building is doing well heading into its first winter. Another project of note was the large industrial building (4,000 square feet, 17-foot high walls) we retrofitted with bales set on edge. Lining the inside of a prefab steel building with bales on edge, we tied the bales to the frame with wire and used block ties against the face of the bales. Because the building was already sided, we would not be plastering the outside of the bales. Instead, we left an 8-inch air space between the bales and the steel siding and used Typar housewrap to protect the bales from too much air infiltration. It was difficult to get the walls straight without being able to "bash" the bales from both sides. The result was quite a wavy finish. The walls did experience a few large cracks, likely due to the extreme weight of the plaster on only one side of the bales. The biggest lesson learned on that job was that straw bale has a long way to go to become integrated with the rest of the building trades in industrial applications. Because prefabs' efficiency is what industrial building is all about, some of the indistinct nature of bale building that we take for granted in the housing market is a source of nightmares for industrial contractors. The last large project I described was actually a fairly small home (1,800 square feet). Included in that small footprint was a complete three-story tower, all done in straw bale. The finished wall height at the top was 32 feet. We used a lightweight, modified post-and-beam system to frame the building, which worked very well as a method of combining moderate lumber consumption to allow us to determine exact heights for all three stories with a seamless finish with no evidence of the framework. We had "fun" plastering to the full height (a rented Skyjack is every plasterer's best friend), and our old stucco pump was able to beat the heavy amount of head we asked it to cope with. The framework for the building was an engineering first in our experience: the engineer actually took the strength of the finished bale walls into account when designing the framework, so that we were not grossly over building the structure. That kind of thinking will go a long way toward making buildings that use resources efficiently. The finished home is visually stunning, and quite a departure from typical bale architecture. The next part of my talk was where things got interesting. I spent some time sharing some ideas and theories Pete Mack (my business partner) and I have developed over the course of the dozen or so large buildings we have done, and especially over the course of the many workshops we have taught. These ranged from little tricks we have picked up to make bale work faster and easier (cutting and retying two-string bales without needles or bale presses, for example) to major departures from bale building norms. The most lively discussion centered around our move toward building loadbearing structures with two-string bales set on edge (14-inch side). Having just completed our first building in this manner, I was excited about the lack of sponginess in the walls, the level-ness at the top of the wall, plus all the space-saving and bale-saving bonuses of using bales on edge. It was interesting for me to see that what we thought was our own innovation was actually tried and tested the good old Nebraska way - for in Matts and Judy's slide show of historic Nebraska homes, at least a couple of the builders used the bales in this orientation. This gave me a lot more confidence in the intuitive suspicion I had that using bales in this manner would make for a wall at least as strong and long-lasting as with bales laid flat. I also outlined an experiment-in-progress: the cutting of window openings into bale walls after plastering, rather than building bucks to hold the shape of the window in the straw. The idea was to save time in wall stacking (way less custom-sized bales required), save lumber (the frames for less-than-gigantic windows do not need to be structural) and allow some flexibility in the placement and sizing of windows. Well, I came home and finished the experiment, and it was a success. It was relatively easy and quick to cut the holes in the plastered walls (though it would have been even easier if the plaster were green rather than two-weeks cured; and if I had not applied the full thickness of both coats of plaster to the entire window area. I cut kerfs (a saw-cut to allow the material to bend to the cut side) into the plaster using a masonry wheel on my Skilsaw (though a diamond blade on a grinder would have been better), and matched them on the other side of the wall by carefully measuring from the floor, ceiling and corners. I tested the accuracy of my alignments by passing a bale needle through the completed kerf to the opposite side of the wall. Tapping the needle through the plaster on the opposite side, I could tell if the lines I had drawn were in the right place. Then I cut the kerf in the other side of the wall. Then came the fun part: I inserted my 15-inch chain saw in the kerf on one side and cut through the straw until it came through the kerf on the other side. I then continued cutting until I had gone clean through all four sides. Then I pushed from inside out (keeps the floor cleaner). There was a fair bit of friction remaining, even though the bales were cut clean through. But the chunk of bale and plaster wall, thumped steadily, did pop right out. I was left with a surprisingly clean hole in the wall, with only a bit of loose straw, which was easily swept away. Although I had already built 2x6 frames to go into the spaces, a lighter 1x6 or even 1x4 frame would have sufficed. The frame was drilled and pegged into the bales with 12-inch dowels, the window fastened in place, and the final coat of plaster used to cover the frame and join with the rest of the plastered wall. On the inside, the bare straw around the window required a scratch coat before brining the finish coat in to blend the seam where the cut was made. One unforeseen advantage to cutting windows in this fashion is it becomes very easy to do beautiful sculpting work around windows, because the straw stays in place even when the strings are cut. Arched and rounded openings take only a few minutes with a grinder and do not require lots of diamond lath for plastering. I am sure as we repeat the process, we will develop better techniques and tools. Even in its infancy, it saved time, money and materials. The Nebraska conference was the beginning of a lot of conversations and friendships for me, and I hope that all of us can continue to find ways to make time to keep these important, and often entertaining discussions alive. We all have so much to learn. Chris Magwood can be reached in Canada at 613.473.1718 or via E-mail: cmagwood@kos.net. Website address: www.mwsolutions.com/straw |