Photo by Joe Silins
I continued my education by taking courses in permaculture and water-harvesting design, which helped me realize that being stuck behind a desk for 30 hours a week reviewing payroll reports just wasn’t for me. When a part-time job opened up at the nonprofit I was on the board of, I jumped at the opportunity. I would be leading community workshops and trainings in water-harvesting system installation in Tucson and along the Arizona-Sonora border. To make ends meet, I also got a part-time job working for a residential contractor repairing homes and building custom homes from the ground up. This was a mentally and physically challenging time; I was learning a lot of new skills, and my body was pushed to its limits between the intense physical work and the harsh Tucson summers.
Volunteers helped raise and plaster the straw bale walls in exchange for a learning opportunity.
Photo by Joe Silins
In the midst of all this learning, I continued to be drawn to natural homebuilding. While traveling, I discovered a natural building training center near Mexico City, and I took a weeklong natural building course there. At the end of that trip, I resolved to return to Tucson and build myself a cob casita as a means to start living more simply and to put into practice the techniques I knew in theory. After returning to southern Arizona, I reached out to Bill and Athena Steen of the Canelo Project, who convinced me that straw bale was the way to go, given the extreme temperature swings here in the Sonoran Desert. After attending their weeklong straw bale training, I was ready to embark on my guest house project.
I had a basic floor plan for my guest house, and an architect friend of mine helped me build a SketchUp model. That friend ended up moving away, so I found another architect more versed in natural building who put together the plans for submittal to the city. I have a neighbor who’s constantly reporting me to city code enforcement for minor complaints, so getting a building permit was essential.
Photo by Joe Silins
We were able to get a permit for the project using the Strawbale Construction appendix of the 2015 International Residential Code. The 2018 and 2021 updates to this code also include straw bale appendices, and if you build according to these codes, you won’t need a registered architect or engineer to get a building permit. I’m glad I had an architect, though, because drawing the plans myself would’ve been difficult. Arizona’s owner-builder laws allow anyone to build and manage their own project rather than hiring a licensed general contractor to build their home, as long as they don’t plan to rent or sell the project for a year after completion. I got my permit in January 2015, and got to work as the owner-builder.
The structure’s exterior footprint is 450 square feet, but the thick, load-bearing straw bale walls take up some of that space, so the interior footprint is 350 square feet on the ground floor, plus an extra 100 square feet in the loft. The casita has an open floor plan, with the kitchen and living room on one side, and a bathroom and closet on the other, with a loft above. The casita has a gable roof and vaulted ceilings, which help it feel more spacious. It’s comfortable for one person, and would be comfortable for two with the proper storage and organizing systems. A north-side, covered porch provides a great shady space to extend the living space outdoors, effectively adding an extra room to the house.
Large southern windows allow the low winter sun to enter the casita and passively heat the space, while roof overhangs block the heat of the high summer sun during hotter months. The earthen floor provides thermal mass to help regulate temperatures, and it’s a beautiful, comfortable material. Opening windows and turning on fans during certain parts of the day keeps the space comfortable for most of the year, minimizing the need for mechanical heating and cooling. Heat is rarely required during winter. An energy-efficient, mini-split heat pump system provides heating and cooling during intense cold snaps and sweltering Tucson summers. All plumbing fixtures outlet their greywater to the landscape, and there’s a site-built, outdoor composting toilet.
The super-insulating straw bale walls also bear the weight of the roof assembly, drastically reducing the need for lumber in this dry climate. The clay exterior plasters provide protection from driving rains while allowing water vapor to escape the walls. Interior lime plasters also provide breathability, since prolonged exposure to moisture is dangerous to the bale walls.
Photos by Joe Silins
About a year and a half after breaking ground, the casita was far enough along to move into. The building was essentially a shell at first, so since then, I’ve added fixtures and amenities. In addition to showcasing natural materials, the guest house highlights the beauty of salvaged materials. Barn timbers and siding make up the trim and countertops, and lumber pulled from a remodel provides a ladder up to the loft.
Building my straw bale casita was the culmination of my training up to that point, but it was also the inception of my current career path. Just before completing the guest house, in the summer of 2016, I started my own business as a natural building consultant, helping others build their dream homes, just as I have.
Find more information about Joe Silins’ company and see photos of his straw bale guest house at Tierra Buena Home.
Read more about the qualities of cob and straw bale building, and learn how to combine the benefits of both to construct beautiful, functional homes, at Balecob.