When University of Dayton professor Bob Brecha and his wife decided to have a home built awhile back, they were intrigued by the idea of having straw as the key ingredient; stacks of it, covered by mud plaster. And if that sounds flimsy, possibly cold, listen to his story of the making of a strawbale house in Yellow Springs.
The three little pigs used different construction materials, with the lone survivor building with bricks – kind of like some of our stately old homes. The second little pig didn’t do as well, choosing stick construction. Talk to a builder and that’s what they call the houses around here built with 2x4s. The first pig chose straw and might have had the winning choice if it weren’t for the nasty old wolf huffing and puffing and blowing it down. In the Yellow Springs area there are seven houses made mostly of straw, and given the lack of wolves, this turns out to be a pretty smart way to build a house.
A strawbale house uses wooden posts and beams to make a supporting frame. Then bales of straw are stacked between the wooden posts to insulate the walls. After the walls are in place, they’re plastered with a mixture of sand, clay, chopped straw and water – mud, basically. The plaster is about an inch thick and gives the wall more strength, while keeping moisture away from the straw. Strawbale houses have a very earthy feeling, with 18-inch thick walls and rounded surfaces – kind of like adobe. Usually the floors are stained concrete with a radiant heating system buried in the slab, and maybe a small woodstove for additional heat as needed. That’s all it takes to keep our house warm and cozy on a zero-degree night.
People tell us all the time that they like the look and feel of our house – we even give tours. But I’m particularly interested in the fact that it uses only about 25% of the energy of a typical house, while feeling very comfortable. My home heating bill of $100 a year adds to the comfort as well.
If you’re thinking, the price of natural gas has been low the last couple of years, that’s true but I’d be very surprised if those low prices stay with us for a long time. Some history on this.
As houses were built in the early years of this country, energy was cheap and abundant. First, we had huge numbers of trees that needed to be cleared for farmland – so they built houses out of wood as simply as possible, and then used lots of wood to heat them in the winter. Then came fossil fuels, in great abundance, and homes continued to be built with little thought given to energy efficiency. Now as energy more expensive, we do think about the cost. But not everyone can build a new home just get a $100 per year heating bill. We are now learning how to build and retrofit homes to use much less energy, partly through new technologies and partly by using a bit more common sense, but these changes come slowly.
It is fascinating to think about the historical path we took in building homes and how it might have developed differently. Most materials used to build a strawbale house are locally available, and would have been a century ago. What if we’d decided in 1850 to build for efficiency (and don’t forget comfort)? Living in a strawbale house has made me realize that using less energy doesn’t have to mean being cold during 10° November nights.
Bob Brecha is a professor of the renewable and clean energy program at the University of Dayton.
