A Look Inside the Strawbale Walls of this Off-grid Home

The home was designed by Michael Barton with a great deal of input from Robbie and Anke. Michael tailored their building systems to ensure adherence to local building codes.

Michael is particularly proud that they got the first approved septic system in Nova Scotia smaller than 1000 L/day. They could do so by showing that using a composting toilet drastically reduces the need for a septic field.

The primary heat source for the building is the sun, so they oriented the house for maximum solar exposure. South-facing windows allow sunlight to enter in winter to provide heat. A concrete floor provides thermal mass to store heat and reduce temperature swings. They have a wood stove/oven for a secondary heating system that provides cooking and pre-heated domestic hot water. The firewood can be harvested from their property. About their home's thermal performance, Robbie says:

How about that? A house so well insulated that you don't need to worry about freezing pipes! A major bonus in a cold winter climate.

The rough-cut lumber for the house was sourced from a local sawmill, and some beautiful posts were sourced on the building site. To insulate their home, they used 18-inch thick straw bales from a neighboring farm. The straw alone provides an insulation value between R-25 and R-40.

Because straw bales are not a standardized building product, they needed Michael, their engineer, to prove that this thickness of straw satisfies building code requirements. On Michael's recommendation, they also took extra care to air seal around joints with acoustical sealant and tar paper to stop any drafts. Straw bales settle for the first few weeks, so they delayed interior finishing until after settling.

The walls are finished with natural clay plaster, which provides a naturally beautiful surface and helps to regulate humidity in the home. In dark or high traffic areas, the third and final coat contained lime, making the walls brighter and more durable. The clay was as locally sourced as it could be; in fact, it was dug from the ground near the house! The resulting pond now provides irrigation for their garden.

To insulate the pantry walls for excellent temperature food storage, they used a building technique called 'straw-clay slip.' This involves dressing straw with clay and packing it tightly between the wall studs. The clay acts as a binding agent to apply the clay plaster finish directly to the straw-clay slip. This technique was also used for the interior bedroom walls to help with soundproofing.