What is Straw Bale Building?

The first course of bales is always started on a 2x4 curb, to lift the bales higher than the interior floor level, in case of flooding or spills.

There are two basic styles of straw bale construction. Post and beam style uses a structural framework to support roof loads, and the bales are either wrapped outside the framework or in filled between the framing members. While wooden post and beam systems are the most common, concrete and steel frames would also be suitable.

Load-bearing (or Nebraska) style bale buildings use the bale walls themselves to support the roof. Various systems have been used to "pre-compress" load-bearing bale walls to eliminate any "sponginess" from the bale walls and level them. A structural roof plate is placed on top of the walls, and the precompression system draws this roof plate down toward the foundation. The simplest and most effective system devised to date is a series of 9-gauge wires looped through the foundation and over the top plate, and tensioned using a come-along.

There are building code approved examples of both load-bearing and post and beam straw bale homes in Ontario. Many have received bank mortgages and regular home insurance. Much testing has been done on straw bale wall systems, and all tests to date show that they outperform the standard 2x6 frame wall. Fire tests show a burn time more than double that of a frame wall, and structural tests show similar advantages. The CMHC has been responsible for some of this testing, and they are generally supportive of straw bale building.

To date, most building inspectors have required either an architect's or engineer's approval of drawings for straw bale buildings before issuing permits. Reactions from building inspectors have ranged from enthusiastic support to strong skepticism and resistance. Until straw bale building becomes part of the Ontario Building Code, bale projects must be approved on a case-by-case basis.

Straw bale homes can be designed and built in any style an owner chooses, from small bungalow to two-story luxury. Many kinds of outbuildings have also been built from bales, from simple chicken coops to three-car garages and livestock barns. Bale buildings are most commonly finished with a cement plaster (or "stucco") on the exterior and a gypsum plaster on the interior, but any common interior or exterior finishes are practical to use. Bales are a practical building material, abudantly available in most areas, and annually-renewable. It is worth considering using straw bales for your next building project.

We are witnessing a renaissance in the way we build houses. This renaissance, known as "natural building," is where ancient tradition meets a modern pioneering spirit. People seeking to create a home which is healthy, beautiful and sustainable are turning to old/new technologies such as straw-bale construction, cob and permaculture. These rely on local materials and skills to create an architecture rooted in place and community, and an edible natural landscape around it.