Before rendering/plastering can begin you will need to pre-compress the walls or allow the roof to do the job of settling the bales in position. If you let the roof do the compression you will have to allow 6 to 10 weeks for this to take place. This overall compression can be from one inch up to eight inches, depending on the quality and density of the bales.
We then prepare the walls for render by brush cutting the loose straw ends and filling the holes if any with a cob mix.
Once the walls are compressed you are then ready to start rendering. However before you commence rendering you will need to install the electrical and plumbing conduits. This will require the services of licensed tradesmen. Details of electrical and plumbing installations will depend on the design and layout of the building.
Rendering before the bales have compressed can lead the plaster cracking, which will lead to moisture penetration and subsequent deterioration of the bales. We have concluded that the pre-compression of the load-bearing walls is an essential part of the construction method, and will lead to a very strong wall system.
We prefer using all thread tie down bars in pairs every 1.8 metres and beside each window and door openings. This method is very strong and accurate giving level roof plates. We also use the high-tensile-wire-and-gripple system of pre-compression. This is a low-cost method and suits strawbale construction.