Timber and steel are the two most common frame materials. We chose timber because it is a renewable resource and locks up carbon, was (slightly) cheaper and could be made here in the Great Southern. Rainbow Frame and Truss in Albany kindly took on our complicated job, with the pre-fabricated frames and trusses delivered in two truck loads.
The strawbale walls were made with large LVL planks spanning the length of the wall, held up by timber posts set into the concrete pad with steel saddles.
The internal walls and the external walls of the wet areas (bathroom and laundry) were standard timber stud frames. Strawbale was not used in these places because of the amount of room they would take up inside the house, and concerns regarding waterproofing. Strawbales can be used for plumbed walls, but we chose not to.
Internal walls were clad in sheets of engineered compressed plywood, instead of the standard plaster sheeting. These were required in a few places within the house to protect against torsion (twisting), but we chose to carry the material throughout. The final texture is very organic and matches the house beautifully – despite it being rather difficult to paint.
The roof frame is a trussed roof, and was very much like a giant jigsaw puzzle! The trusses were pre-fabricated to specifications, installed by us on-site and then finally the ‘tails’ trimmed to the specified eaves length to ensure correct shading and light penetration through the windows.
Timber was also used for the roof and ceiling battens.