Straw Bale Roof Insulation

Bales of r40 with ceiling airspace anticon then roof would rate somewhat above r40 and the standard r38 andrew talks about.

Straw bale roof insulation.

Without an exterior stud wall most straw bale walls have an r value of r 33 or less. Make sure it s in good condition no rot termite damage cracked boards etc. 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. 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. 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. What you want is closer to the insulative side.

This implies that bales r factors would be considerably higher. To improve insulation because i love everything about straw bale houses i was wondering if we could retrofit straw bales by removing the weatherboards and the internal plasterboard leaving just the wooden frame and windows then put the straw bales in like you would if building a wood framed straw bale house from scratch. First you need to check the strength of your roof system. Are there any very long spans.

However if you want to use bales you can use an assembly that looks something like this. A bale is 360mm deep. 2 6 tongue and groove planking over beams girders to be engineered per the loads and spans. 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.

Strawbale insulation is tightly packed and 18 thick. 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. It can be made into different grades closer to one extreme or the other. Personally i stick with light weight insulation materials in the roof and leave the bales for the walls.

The two layers of batts and 3 of rigid foam andrew describes would be about 240mm deep for r57. Owen geiger yes you can use straw bales as roof insulation. The straw clay material is a sort of hybrid between pure insulation straw baled or not and pure mass cob for ex.