Information on strawbale
By Muttnboofer
@Muttnboofer (154)
United States
1 response
@ladyluna (7004)
• United States
27 Mar 07
Hi Muttnboofer,
I have not built a strawbale home, but did help to build a strawbale outbuilding. Specifically, a few friends and I built a large water shed for my well out of strawbale.
Tips? Sure, I'm happy to share the highlights of what we learned, which was alot!
1. Make sure that your footing is more than sufficient in width.
2. Use straw that is baled specifically for home building, not agricultural purposes. The reason is that building straw bales are wrapped tighter, and are strapped duo-directionally. This makes for a stronger structure.
3. Make sure to use weatherproofing wherever the straw comes into contact with both the concrete of the footings, and the wood or steel of the wall, roof structure. You can purchase handy rolls of sky blue rolled polystyrene weather barrier at most home improvement stores.
4. Don't skimp on the rebar. This essentially forms the vertical strength of your building. I'm not sure if strawbale codes have been amended to include horizontal rebar as well. However, if I were to do this again, I would place incremental rebar through the bales horizontally as well as vertically.
5. Make sure to lathe the straw tightly. If the lathe (chicken wire) is not taut, the plaster will be wavy and lumpy.
6. Don't try to rush the plastering. It's going to take as many layers as it takes. Our project was four layers, with the last being the color coat. And, you will need to keep the surface moist as the layers dry. Lightly dampening with a hose at least every 12 hours will help the plaster cure that much stronger. Unless, you are using quick curing plaster. Even so, keeping moist is very important.
7. Make sure to allow for sufficient cross ventilation in the roof structure. Unlike most other building processes, plastered strawbale cannot breath. And, the tendency is to absorb moisture, so you want to allow for plenty of ventilation in the trusses or rafters.
8. Comparatively speaking, this is not an inexpensive building technique. So, make sure you have more in the budget than you think you'll need. You sure don't want to start this, then run out of money before all of the bales are plastered. The weather and bugs will destroy exposed straw. So, once you start, you must forge forward until it's done.
I would say that those are the highlights of my experience. If anything else comes to mind, I'll pop back in here and share it.
Good luck, you're gonna' learn a ton. It's hard work, but worth it.
@Muttnboofer (154)
• United States
28 Mar 07
Thank you so much for the information. It sounds like we might do better to start with a smaller building for getting the feel of it and get some practice before we go to anything bigger.
1 person likes this
@ladyluna (7004)
• United States
29 Mar 07
Hi Muttnboofer,
Your welcome! If you are planning on doing the work yourself, rather than contract it out, then you're probably right about testing the waters with a smaller project.
I will say that despite the initial cost and labor involved, strawbale offers two clear advantages over stick building. One being greater durability, and the other being the insulation factor. Our water shed always stays nice and cool in the summer. And, in the winter a single lightbulb keeps the well pipes from freezing. As I recall, the 'R-value' of strawbale is in the high 30s.
Having said that, I would be remiss in not pointing out that other building technologies may offer an even stronger, longer lasting alternative. Recycled tire (or earthship) construction is one alternative. Mice and bugs won't eat tires or dirt, which is what's generally used to fill the tire cavities.
There's also poured pummice & concrete in preformed polystyrene blocks. Neither of which is 'green' in and of itself. This type of buiding can offer a solid starting point for incorporating later phases of 'green' construction -- like solar reflective roofing materials and passive/active solar hot water and energy collection systems, i.e. photovoltaics and burm walls. Which give the homeowner the option to both reflect and collect solar heat for different purposes.
I will admit that if I had it to do all over again, I probably would not go with strawbale now. The reason is: the straw inside the walls will always be organic and therefore degradable. I fully expect that at some point the well-house will have to be rebuilt. Only because there's no way to be certain to keep the mice and insects out. Mice will eat through plaster to nest, which will allow both mice and bugs to access the core structure - the straw.
Perhaps this is more info than you were seeking, but I thought it best to follow through with a full perspective.
