Replies

1. 
   Bob_Rozett | Feb 16, 1999 09:43am | #1

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   I have friends who built a strawbale solar house, it's warm and very comfortable. However they have a roof on it, will your wall be waterproof?
   A little roof?

2. 
   Guest_ | Feb 16, 1999 10:28am | #2

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   John,

   Straw bales will work fine as a yard wall when covered with stucco, if the bales stay dry. Hay bales will not work so well. Make sure you have straw, and be sure that it's dry. Also, I don't know how much snow you get, but if you get a real lot, that might be a problem.

   Typically, straw bales used in any building application are set at least 8" above the finish grade on concrete stemwalls. Rebar on 2' centers is turned up out of the concrete in a pattern that alternates side to side, with enough vertical rebar above the concrete to impale at least one and a half bales (usually about two feet of rebar).
   Usually there is a PT lumber sill bolted to the top edges of the stemwall (both edges), with pea gravel filling the space between the lumber sills. These sills keep the bales off of the concrete and provide a convenient attatchment for your stucco netting. Set your bales just like block, two over one, one over two. Vertical pins (rebar, dowels, 2"x2", whatever you have) are a good idea to help hold the wall together. Give yourself some additional support (CMU columns) every 20' unless the wall curves a lot or isn't too high.

   Cap the wall with a single run of 30# felt on top (a little extra waterproofing), stretch your stucco netting from one sill, over the wall, down to the other sill, pull it tight. A little Anti-Hydro in the scratch coat will help with the waterproofing, too.

   If you want more info, run a net search on strawbale building. There is a lot of info posted on the Web about strawbale construction. Some of it is useful, some is not. It will be immediately apparent which is which (it seems to me that some of these "alternative" builders have somehow assumed some "alternative" laws of physics). If you use good construction practices combined with knowledge of your climate, you will likely be happy with the result.

1. 
   Guest_ | Feb 16, 1999 09:03pm | #3

   *The hot box tests performed on a full scale straw bale wall at ONRL (Oak Ridge National Lab.) and presented at Thermal VII, showed that the claimed R values were not achieved with hand applied stucco on the outside and furred drywall on the inside. The way that they reached full insulation potential was to use pneumatically applied stucco inside and out.

1. 
   Guest_ | Feb 17, 1999 08:53pm | #4

   *I'd cant (slope) the top of the wall so water and debris will drain off. Makes it somewhat self-cleaning. Probably a good idea to have a smooth steel trowel surface on the top rather than a textured surface, so dirt and ice don't accumulate there. Even where the top is low to the ground, such as an 18" high seating area, I'd slope it slightly to avoid ponding and aid cleaning.Bales are so wide and irregular its not practical to put metal cant flashing on top. A ceramic tile top would be nice but may be overly elaborate.In some climates, streaks may appear on the downhill side of a sloped top from dirt or moss. If that might be a problem, consider draining the top twords the less visible side.You'll need some kind of foundation like concrete and stucco weep screed to keep moisture out of the bales to discourage wet rot and burrowing insects, earthworms and rodents. Otherwise the bales will decay and shrink and you might end up with a stucco shell over compost!

1. 
   Guest_ | Feb 20, 1999 10:54am | #5

   *I don't have any personal experience using straw, but I remember a couple of pigs that tried it. Seems a big bad wolf huffed and puffed...I think they started using brick after that.Blue

1. 
   Guest_ | Feb 20, 1999 12:19pm | #6

   *Visited some folks (artsy-fartsy craftspeople) in Port Townsend, WA who had planned to do straw-bale construction. They did their perimeter fence that way, and that came out fine - looked rounded and maasive like adobe. But they had run up against the building department vis-a-vis structural and earthquake concerns. They didn't want to get the engineering done and (likely) add shear wall, etc. And the building department wasn't budging either.

2. 
   Guest_ | Feb 20, 1999 06:19pm | #8

   *.... speaking of straw bale construction and new age "alternative" laws of physics... went out to look at a reno job a few weeks back, and this fellow had ripped out the old stone foundation of his house so he could install a fancy new straw bale foundation all around, much better R-value you know... sitting right on the dirt, no parging inside, I would hope or assume he at least put something on the outside, but was afraid to ask. When I casually asked him what the building inspector thought of his new foundation, he came up with that original line that building inspectors only exist so the township can find out about changes in your house so they can raise your taxes... the $125,000 worth of renovations he wanted done were also based on some "alternative" laws of financing, the banks gave him a big thumbs down.

3. 
   John_Fuhrman | Feb 20, 1999 06:19pm | #7

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   Does anyone have experience (good or bad) with stucco finishes over hay bales? I may use this type of low wall (about 2 ft. high) as a landscape divider in the yard. This would be in a cold climate, Montana. Thanks for any advise.