STRAW BALE

Advantages

Carbon sequestering—strawbales a waste product in some regions, generally available locally.
Thickness of bales provides better than Code insulation performance.
Fire-resistant properties.
Straw and plaster combination delivers excellent acoustic insulation.

Disadvantages

Only an infill material, structural timber frame needed to meet
earthquake resilience standards, increasing costs and time to build.
Wide eaves (or cladding) are needed to protect from driving rain.

Suitability for self builders

Bale-raising a great opportunity for bringing together a group of unskilled labourers.
Plastering feasible for DIY.

In NZ conditions

Crucial to protect bales from moisture; must be kept dry during
before, during and after construction.
Quality of construction detailing and plaster application is critical.

Popularity

Examples can be found in many parts of New Zealand.

Straw Bale Construction

Straw bale houses have enormously good insulation values, and can be built with relative ease and speed. They may be load-bearing, but more often they incorporate a post-and-beam frame. The bales are finished with a coat of plaster – often earth or lime based.

The design issues are similar to earth buildings, but the need to avoid moisture and weathering is even more crucial. The bales must be dry before installation and remain dry throughout their life, as once wet they are more likely to compost than dry out. The construction detailing and plaster coatings make or break straw bale construction.

Straw bale houses were developed in America and are rising in popularity.

Those wanting to build a straw bale house would need to engage an experienced designer, and do the analysis to apply for a building permit as an “Alternative Solution” under the Building Code.