Matthew Nistico wrote:why the hell aren't people starting domestic commercial bamboo plantations?!
Matthew Nistico wrote: straw bale builders will ship in their bales on trucks from 700 miles away, yet fail to recognize or admit that in doing so they have effectively negated any advantage those bales might have had over other building materials
This is the part that I don't understand, and I am really hoping that someone can explain it to me: why would anyone desire to ship bales across the country to build a straw bale home?
Brad Vietje wrote:Hi All,
Quick response to Jeff's question:
Straw is usually seen as a "waste" product after the seed heads are harvested, and in some areas, it is simply mounded up and burned (!)
Hay, on the other hand, has food value for livestock, which could mean that its "higher purpose" -- if there is such a thing -- would be to nourish critters. Even more importantly, the inherent food value makes it much more attractive to rodents, or even deer and moose! One fear a lot of people have about a wall system made of straw is that small fuzzy woodland critters will want to either eat your walls, or nest in them. Nesting is still a serious consideration, but not using an attractant such as hay can help avoid this problem.
The walls are coated with thick, hard plaster on both the inside and outside -- usually in excess of 1" thick -- so critters have to really want to get in to gnaw and/or burrow through that. In dry climates, that plaster can contain Portland cement, so it's more like adobe. In moist climates like here in New England, cement is a serious no-no, because it doesn't allow moisture out of the wall very well, and it tends to crack more when the timber framing expands and contracts with seasonal humidity changes. For wet climates, a natural earth plaster is preferred, which is composed of clay, sand, chopped straw, and cow manure. The plasters on the outside also contain lime, so they are harder, and crystallize to form a more concrete-like plaster that still allows moisture to escape. Earthen plasters are usually applied in 3 distinct layers, and the composition in each layer can be fine-tuned to meet the local climatic needs. Thus, the exterior plaster has increasing amounts of lime as you go out from the bales, and then 3 lime washes, before an outermost layer of lime paint.
We also set our bales on an 18" toe-up of insulated concrete blocks to keep them away from back-splash from rainwater, and also help deter any ambitious rodent. This layer is coated with a thin layer of fiber-crete, and pretty tough. When properly built and sealed, there should be very little oxygen inside the walls (though this can be really tough to achieve!), so the little mousies might not like it very much, anyway. The bales are also tied with higher tension than typical hay bales, and in our case, bound together with binder straps like those used in pallet loads of stuff, so it's pretty firm stuff. So far, we had a cute little Red Squirrel try to jump in the front door once (and thankfully failed), and try to get in the vents for the root cellar (hardware cloth!), but so far, at least, no signs of mice.
There are a number of straw bale homes in VT & NH, so if you want to go see one and visit the owners, send me an e-mail off-list, and I can ask the folks I know who build with straw, and they should be able to find one somewhere near you. I'm up in the greater Woodsville area, north of Hanover & Lebanon, if that happens to be anywhere near you.
Dave Hanson wrote:Humans have grown hay (not straw) for winter forage for their animals for hundreds of years, with very good reason. They couldn't keep healthy animals without it in many climatic areas. To suggest otherwise is simply not correct.
Foam buried inside masonry is an excellent option as well. Masonry is a heat battery and plastic foam has a crazy high R-value. Foam and Cement may be high energy products, but if you aim for R-30 to R-50, then you will end up saving way more energy in the long run. Even if you burn something obscene like tires or something.
Vern Faulkner wrote:The Lady and I looked, extensively, at straw bale as a building technique, and may still build some small outbuilding with such things - but not our main structure. Living in New Brunswick (the province, not the New England jurisdiction), we face some relatively humid conditions... too humid, in our mind (and others, such as Jim Merkel) to be a viable technique. Also, we're far away from any straw, meaning costs would increase.
For that reason, we've abandoned straw and opted instead for slip-form masonry (a la Nearing), and XPS foam... (recycled, I should note.)