Straw-bale construction is a building method that uses bales of straw (commonly wheat, rice, rye and oats straw) as structural elements, building insulation, or both. This construction method is commonly used in natural building or "brown" construction projects. Research has shown that straw-bale construction is a sustainable method for building, from the standpoint of both materials and energy needed for heating and cooling.
Advantages of straw-bale construction over conventional building systems include the renewable nature of straw, cost, easy availability, naturally fire-retardant and high insulation value. Disadvantages include susceptibility to rot, difficulty of obtaining insurance coverage, and high space requirements for the straw itself. Research has been done using moisture probes placed within the straw wall in which 7 of 8 locations had moisture contents of less than 20%. This is a moisture level that does not aid in the breakdown of the straw. However, proper construction of the straw-bale wall is important in keeping moisture levels down, just as in the construction of any type of building.
No, in fact they are more fire resistant than a typical framed house. Individual straws will burn, but a straw bale is so compressed, there is not enough oxygen for combustion. It is like trying to burn a phone book. Straw also is high in silica content, causing the surface of the bale to char, and block the flame from reaching farther into the bale. In laboratory tests in New Delhi, a plastered bale wall easily passed a two-hour fire rating, which is required for commercial construction.
