By Larraine Roulston:
Living in a straw bale home became a reality when my husband Pete and I purchased land in northern Ontario. We were familiar with sustainable straw bale home structures and knew that the thickness of the bales would result in more energy efficiency –warmer in the winter and cooler in the summer.
While designing a small one-bedroom bungalow set on a concrete pad, we searched on-line for the straw bale experts we required. By also locating a local farmer who met our needs for approximately 400 tightly packed dry rectangular straw bales, we were set to go.
When the plumbing and in-floor heating were in place, we poured the concrete pad, erected a post and beam frame, and called upon our straw bale crew of four who camped on-site. Pete helped with construction, and I was tasked with many detail jobs and meal preparations.
During the last stages of shingling with Enviroshakes –a roofing product made from post-industrial plastics, agricultural fiber and reclaimed tire rubber –we arranged for the delivery of the bales.
Before the first tier of bales was laid, two wooden rails (3”high and 13”apart) were placed around the perimeter of the foundation. The resulting gap was filled with small styrofoam pieces. The crew notched the bales to fit around the door and window bucks, beat the walls for alignment and stapled diamond lath to create a contour around each door and window. To allow the plaster to adhere and prevent cracking, strips of water resistant yet breathable wrap, trimmed boxboard pieces, and diamond lath were stapled in place. Plywood strips were nailed at baseboard level to serve as a plaster stop.
After the bales had been stacked, shaped, stuffed with loose straw, and finally sewn using mesh and sturdy twine, a mortar plaster was applied to the walls. We ordered one load of coarse sand and bags of lime cement, and rented a mortar machine. Water was pumped from the lake. It took one week of hard labor to cover the 160-foot perimeter with one coat of ½inch plaster, both inside and out. The first coat was scratched to allow the second coat to adhere properly, which was applied the following year when weather was more suitable. To cure the plaster, the walls had to be dampened twice a day for a week.
Although a straw bale home has fewer material costs such as siding and insulation, its construction is more labor intensive. If lucky, you can save money and time by soliciting help from family and friends. Many owners benefit from the number of eager participants. With all its minor challenges, building a straw bale house is reminiscent of old-fashioned barn raising. It is a child friendly site where youngsters are able to climb on bales, stuff straw into cracks and create “pig & wolf”signs.
To promote straw bale construction with its intriguing curves and deep windowsills, we offered tours to future homebuilders. Many local tradespeople also dropped by to view the process. Municipal personnel were helpful in passing all the required inspections.
Once a unique idea, this nearly lost art is enjoying a revival and has blossomed into a mature and highly developed construction technique using sustainable materials. The concept is being taught through workshops and courses at some colleges. Many straw bale websites and books are also available.
Larraine Roulston authors the Pee Wee at Castle Compost series at www.castlecompost.com