From installing the window and door bucks to topping the walls with bond beams, this crew of four completed the exterior walls on this DIY 720 sq ft house in four days. Next comes the roof!
Barbara and I retired from teaching high school the last week of May, 2009. With the help of our neighbors, Dan and Anneke, we moved lock, stock, and barrel from Tucson to Cochise with a couple round trips in a pickup with horse trailer, Chevy Blazer, and Barbara’s little Corolla. After a day of resting from the move and getting organized, we were ready to build. This blog is not just a chronicle of our straw bale house walls going up, it is a “thank you” to our neighbors, Dan and Anneke. They not only got us moved, but devoted their time and energy to helping us get our walls up. They are the kind of people that put the “good” in good neighbor.
About a week before we retired, our ranch supply store delivered about 180 straw bales freshly baled and tightly packed. Bales from different machines can vary in size, number of strings, and the length of the straw strands. Our bales averaged about 4 feet long x 15 inches high x 24 inches wide. The bales we bought had long strands, which made a variety of building chores easier than a chopped straw bale. The market here at that time was $6.50 per bale. Thus, our walls, without rebar pinning or bucks, cost us $1,170 delivered. The bucks and rebar pinning added a couple hundred dollars more.
To accommodate openings less than 4 feet, we had to retie bales into shorter lengths using baling twine and bale needles. Retying with long strand bales was a dream compared to the choppy bales our neighbors used. A long-strand bale holds its shape, while a short-strand or chopped straw bale tends to crumble when retying. Ugly!
To retie our bales, we measured our new bale length and pushed a bale needle through the bale near one of the existing strings. We pulled a loop of new baling string up through the bale and tied off in both directions, creating two new shorter bales. Once a new string was tied next to all three original strings and the two new flakes were tight, the old string was cut and put aside for the next use.
I made the bale needles from a couple pieces of galvanized fence end strapping that were salvaged from a neighbor’s project. Our needles were about two feet long, excluding the handle. I bent the handle in my vise and used a grinder to cut a retaining notch and make a point on the needle. Cost = Zero. It is possible to purchase “professional” bale needles from a variety of resources, but why?
Wall raising day arrived. We were rested and ready to go. June is hot here in southern Arizona and our neighbors have their own ranch to tend, so our work day usually started about 6 a.m. and stopped about 1 o’clock in the afternoon. Our first day was something of a shake down. We got our tying system running well and the door and window bucks installed and the first course of bales on the stem wall. It felt good to get started. After Dan and Anneke left, we did clean up and got ready for day two.
On the second day, the wall grew to four rows. We began pinning the wall at the fourth row. Five foot lengths of 3/8 inch rebar were cut and driven through the bales every two feet to stabilize the wall. We made sure to drive the rebar entirely into the top bale to avoid tripping or kneeling on an exposed end. With the bottom course of bales firmly pressed unto pins sticking out of the stem wall and the additional rebar pins every additional third course, we had a strong wall.
At the corners, we impaled each corner bale on a piece of 3/8 inch all-thread three feet long. The first section was anchored in the stem wall. We joined each length of all-thread with a long nut to give us an adjustable mechanical tie from stem wall to bond beam on each corner. This helped secure and level the bond beam. We were careful not to cut any bale strings as we drove the rebar pins.
There are many methods of stabilizing straw bale walls. Interior pins, exterior pins of bamboo tied through the bales, strapping and on and on. If done well, all will do the job, I suspect. We found that exterior pinning caused cracking in the plaster on the Annex wall, so chose interior pinning for our home.
As I am getting to be a bit “long in the tooth” and much closer to 70 than to 60, I don’t try to buck bales above four courses anymore. When I was 20, it was a different story, but – Oh Well!
As a consequence, we used Dan’s little tractor bucket and a scaffold to work the wall as it rose. I must admit that walking along a wall made of a single row of bales as it shifted and moved is no longer a source of entertainment for me. And when the job involved reaching into the bucket of the tractor with a hay hook and dragging a bale into place on the wall - well, I’m glad it’s done.
Once the bond beams and final pinning was done, the wall didn’t move at all and working the trusses in the next phase of building was a breeze.
By the end of the third day, we had the end in sight. We had originally intended to build a wall only six courses high. But when we were through with the sixth course, we discovered that the door and window spaces had left us enough material for a seventh course.
Nothing in my body wanted to do that as I was one tired puppy. But in retrospect, I’m happy we pushed the wall up one more level. Our interior ceilings are about 9 feet now and, although our house is pretty small, the fact that the interior space is pretty open and the ceilings are high makes it feel much more spacious.
The fourth day was comparatively easy. We had few bales to cut and tie as we were above the doors and windows. We had our system down pat by now. The job was finished with lifting one last row of bales and the placement the bond beams. Each 8 foot section of bond beam was attached to the next with carriage bolts and shimmed level.
We drilled holes and drove our second round of rebar through the bond beams and down three courses of bales to further strengthen the walls. The protruding all-thread on the corners was fastened with a large wood washer and a steel 1 1/2 inch washer to lock the corners into place. The following day, we began the roof. But that’s another story!
Today, as I write this, it is 103 degrees outside. Our R-42+ walls keep our inside temperature about 68 degrees with the help of a small evaporative cooler that runs on low setting and isn’t cranked up until late afternoon. This past winter was cold for Arizona. We had a couple days in single digits, the lowest being 2 degrees above zero. We heat with a small wall-mounted propane heater. When we went to bed on the coldest night, the interior of our house was 70 degrees. We turned the heater off at 8:30 p.m. and, when I got up at 5:00 a.m., it was 62 degrees in the house. Straw bale homes are great!