Straw Bale Roof Insulation

Strawbale insulation is tightly packed and 18 thick.

Straw bale roof 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. For straw bale this can pose a problem in keeping the walls free from direct moisture. Personally i stick with light weight insulation materials in the roof and leave the bales for the walls. 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.

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

First you need to check the strength of your roof system. This implies that bales r factors would be considerably higher. Owen geiger yes you can use straw bales as roof insulation. However if you want to use bales you can use an assembly that looks something like this.

The typical straw bale is bound twice and is approximately 900mm long 350mm high and 450mm deep. The quality of insulation that a straw bale wall provides depends on a number of factors including the way the bales are stacked the way the bales mesh with the roof s insulation the type of post and beam structure or if loadbearing the type of top plate the type of plaster used the quality of the plaster work and the design of the house itself among many others. A bale is 360mm deep. The two layers of batts and 3 of rigid foam andrew describes would be about 240mm deep for r57.

A straw bale is very suitable as infill nonload bearing insulation for timber frame buildings with either an external render or timber rain screen finish. Straw enables vapour permeable walls which are locally sourced and have low impact for construction. Bales of r40 with ceiling airspace anticon then roof would rate somewhat above r40 and the standard r38 andrew talks about. Make sure it s in good condition no rot termite damage cracked boards etc.