Straw Insulation

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.

Straw insulation. The r value of strawbale varies between studies but is mostly consistent. Strawbale insulation has been studied and tested in some of the coldest places in the world. The effect of moisture on the r value of a straw bale wall is more significant than with typical insulating materials because the energy required to redistribute moisture within the insulation is large compared to the energy flowing through the wall each day. The values fall between r 2 38 p in parallel with the straw and r 3 05 perpendicular to the straw.

Straw is made of cellulose which is a poor thermal conductor surrounding pockets of air also a fairly poor thermal conductor. If straw is relatively loosely packed i m not at all sure you will get much insulation value especially if it isn t sealed as the air flow will simply pass between around the straw stems. It can be made into different grades closer to one extreme or the other. Low embodied energy unlike manufactured insulation materials straw is natural and non toxic plus it doesn t require much processing and delivery to a building site.

Light clay straw insulation posted onapril 12 2016bychris magwoodinmaterials and techniques on april 10 a workshop at endeavour led participants through the theory and practice of making wall insulation from light clay straw also known as straw clay slipstraw or econesttm. How do straw bales provide insulation. The thicker the bale the better the r value. The sheer volume of the straw bale in combination with the insulative qualities of the material account for its excellent thermal resistance.

Straw bale walls are very well insulated when built correctly can have an r value between 40 and 60 depending on the thickness of the wall there are many great resources out there that discuss the insulation characteristics of straw bale. 3 less wood for the frame replacing stick frame walls with bales can cut by half the amount of timber needed in a modern home reducing demand on forest resources. The straw clay material is a sort of hybrid between pure insulation straw baled or not and pure mass cob for ex. Straw bale walls are at least eighteen inches thick.

This construction method is commonly used in natural building or brown construction projects.