Straw bale walls for house extension construction.

 This eco friendly building technique for the walls of a dwelling has gone through several experimental processes and again has appeared several times on television.

It will never take off as a mass building product in my mind and is really only suited to the one off properties for the more eccentric home owners wishing to make statement and not constrained by tight sites or planning policy.

Essentially the straw bales are prepared from selected straw or reed and tightly bailed to a preset size to be used as the main building blocks laid in stretcher bond but without any mortar. Pins are usually inserted to tie the bales together and lateral restraint for the walls is provided by the roof again pinned to the top of the straw bales.

One system I saw simply used the straw bales as infill materials between a post and beam timber frame of house.

Straw has great thermal properties and the internal and external surfaces of the straw bales can then be rendered with a lime based mortar such as the hempcrete system previously mentioned.

Just how long term this system proves to be is very much dependant upon maintaining the internal & external protective coverings to the straw bales to prevent rodent & insect attack. The smallest chink will allow the blighters in.