Straw Bale Roof Insulation

For straw bale this can pose a problem in keeping the walls free from direct moisture.

Straw bale roof insulation.

First you need to check the strength of your roof system. If you re wondering what the r value of strawbale construction is then it depends on a few things. A good time to use this roof is obviously when the budget is tight or if you want a larger exposed side of the structure as in a greenhouse or in cooler climates. The two layers of batts and 3 of rigid foam andrew describes would be about 240mm deep for r57.

The straw clay material is a sort of hybrid between pure insulation straw baled or not and pure mass cob for ex. On end or flat. The density of the straw how long the straw itself is as well as the moisture content how well the gaps are filled between bales and other things like how it s stacked. 2 6 tongue and groove planking over beams girders to be engineered per the loads and spans.

Strawbale insulation is tightly packed and 18 thick. In a straw bale house these bales form the walls insulation and framework all in one with some additional support from wooden beams wherever they re necessary. It can be made into different grades closer to one extreme or the other. Are there any very long spans.

Bales of r40 with ceiling airspace anticon then roof would rate somewhat above r40 and the standard r38 andrew talks about. The typical straw bale is bound twice and is approximately 900mm long 350mm high and 450mm deep. This construction method is commonly used in natural building or brown construction projects. This implies that bales r factors would be considerably higher.

A bale is 360mm deep. Without an exterior stud wall most straw bale walls have an r value of r 33 or less. What you want is closer to the insulative side. Owen geiger yes you can use straw bales as roof insulation.

Personally i stick with light weight insulation materials in the roof and leave the bales for the walls. A third generation straw bale technique combines a straw bale interior wall with an exterior stud wall insulated with cellulose by ben graham november 17 2014 an exterior stud wall provides room for more insulation. However if you want to use bales you can use an assembly that looks something like this.