Doug and I participated in a 6-day straw bale workshop a few years ago, and I loved every minute of it, but though that was also a round timber home designed by Whole Tree Architecture and Structures, it was a single story building, and the ceiling was pretty level all the way around.
In Underhill House, some of the straw bale walls are 15 feet high, and the combination of branching timbers and constantly but irregularly rising roofline made for a complex straw bale application.
I watched the crew, sweating and muttering, wearing breathing masks as they carved the bales to fit around branching members. Those were some stifling hot days, and all breezes were blocked because the outside of the house is swathed in tarps and burlaps to facilitate the lime stucco’s slow drying and protect the bales from rain.
Now that they have finished straw baling, I asked the team for their feedback on the process.
Prairie Sundance, one of our carpenters, pointed out that straw baling into irregular spaces sometimes felt like “a pain in the ass to people who have a lot of building experience with standardized materials that are designed to be put up rapidly with less skill. You can’t build low income housing this labor-intensive way,” he said.
However, he noted that standardized building materials are “all horribly toxic and are carbon intensive. By creating all these standardized products, the building industry has shifted the money in the house from people who are working on it to people who own factories.
“The conventional building has a stud wall with rigid foam insulation and vinyl siding on the outside and fiberglass infill and drywall on the inside’ Prairie said. “It’s easy to build and easy to maintain, but in 20 years it has to be ripped off, landfilled and done again.”
As to the “aggravation factor,” Prairie said, “Either you divide up the work so somebody else has to do that, or everybody gets to share in some of that, and I would rather everyone share in some of that. On this project, everybody got to experience some of the aggravation. Brad spent a whole afternoon with his body tucked up behind that beam stuffing from the back forward and Joe was ferrying him up straw clay, but everybody got to do some of that. This crew in general does a pretty good job of sharing that kind of work.”
Tom Spicer, said straw baling was dusty and dirty, “but of course, no one wants to do fiberglass insulation. That’s what this is all about, but straw baling is new and we are improvising.”
Tom wrote a verse about straw baling to add to the Woody Guthry song, Hard Travlin’
I’ve been doing some straw baling, I thought you knowed.
I’ve been doing some straw baling, way down that road.
Stackin’ them bales, stuffin’ that straw, noses wheezin’, forearms raw
I’ve been doing some straw balin’, Lord.
Our construction manager Bryan Dalstrom summed up the process:
“This is my first experience with straw bale, and I’m really happy with it.
“The straw was very good straw. It was dry. It was tightly packed. It was as good as you could get.
“I’m happy with the system that we developed using the firring strips inside and out and wiring them together to compress the bales and create a pretty straight, uniform wall. We installed the exterior firring strips first and as we were baling up, we put wire in at each course and then came in and cut a kerf (a little groove) and tightened the wire up.
“This way we can get a really tight pack because we have something to pack against, and it’s firm. There will be a wire lath over the entire surface. The lathe is nailed to the firing strips and it is strong and secure. This is fully integrated into the timber frame so they support each other. It’s really super strong.
“The firing strips were cut from pines on the south side of the building site. When we did the milling the bottom board was always an inch thick. The rest of the boards were 5/8” planks used in the roof decking, but we had all these 1-inch boards left over. So we used them for the firing strips. And we also made a little nailer along the floor to create a stronger connection between the firring strips and the plate. We used our stickers (left overs from the milling process) for that, which normally just get burned. So we used just about every scrap of that pine. Very efficient use of that material from trees we were originially wondering how to use.
“This is a hybrid home, and I think this is the home of the future, integrating natural materials, green building techniques and high performance standards. Those are our goals at every step and I think we are meeting those goals.”
Categories: Underhill House
It is exciting how it is all coming together, but sad that Prairie noted that is not possible to build a low cost home this way. I would love to see that aspect reclaimed, with more collaborative working on low cost homes with the labour being provided by the new owners as they learn to work on the houses. It is a shame that we have gone towards this specialisation of jobs that then puts the cost of these projects out of the reach of some people, who perhaps need it the most.
Yes, I agree. I think this method could be used for more low cost housing, but what we decided to demonstrate with our house is how middle-income people could consider building, and so we are trying to build a home with enough charm to compete with all the over-grown boxes of ticky-tacky that are gradually covering the tillable land around every city and town.
So while we have a budget and are trying to be as frugal as possible, we are also hoping to appeal to the mind set of middle-income people who may see this house and be swayed to consider some natural or green building alternatives when they build.
I lived in one of those very places for two years and watched those builders throw the buildings up, stapled down and hardly any insulation despite winters that could reach below 0F. Crazy! It certainly is still inspiring though
Starting to feel warm and dry already.
Yes, in deed, Michael. It will be warmer in the winter and also cooler in the summer.
We are also looking forward to how deep set the windows will be in 20-inch thick walls. A couple of the windows will become window seats that we hope will be very inviting spaces.
What is the estimated life span of the exterior using the straw bale construction techniques? I assume this will be stuccoed over, but maybe I’m assuming incorrectly…. Anyway, once again, I’m enjoying following your progress and admiring your courage in leading the way with new techniques.
The exterior is going to be encased in at least a 4-layer coating of lime plaster that should be very durable. This is the same stucco that is still in use on houses hundreds of years old. It does need the occaissional lime wash to repair hairline cracking, but with propper maintenance, these walls should go on indefinitely.
I’ll be blogging more on the walls as they progress. Stay tuned.
And thanks for your kind words.
Thanks for filling me in, Denise!
As someone who is allergic to hay, I’m just wondering if I’ll be sneezing a bit when I come visit you? 🙂
No worries, Lorijo
Just wait till the plastering is done, and the straw will be sealed safely away. The straw has to be covered in a thick, multi-layer coating of plaster on the outside and earth clay on the inside to keep it dry, and it should also keep you sneeze-free.