How thick should straw be to get an R10 value?

[Hookmaster]

Need to insulate some footings on my porch that moved last winter. Looked at 2 inch thick 4 X 8 pink insulation that hs an R10 value. How thick does straw need to be to reach R10?

[cavalierowner]

I've seen staw used a couple times to protect footings from frost heave. In both cases there was maybe 18" to 24" of LOOSE straw. I have no idea what the R value is on that.

Quite a few years ago there was a move on to use hay bales (!!) for exterior walls of houses. There was some testing done on those walls, but I believe every test gave different R values. I suspect it had to do with how much the bales were compressed, the type of straw used, dryness, etc., etc. I haven't heard anything about the hay bale houses in a long time, so I suspect it was a fad that didn't work out. Sure didn't work very well for the Three Little Pigs

[IamZombie]

http://en.wikipedia.org/wiki/Building_insulation_materials#Straw_bales

Saw another one that said not to use loose straw due to increased fire risk.

[hanson]

Need to insulate some footings on my porch that moved last winter. Looked at 2 inch thick 4 X 8 pink insulation that hs an R10 value. How thick does straw need to be to reach R10?

If your porch "footings" moved, they aren't deep enough.

[Surface Tension]

Posts set at the correct depth can still heave as the frost can grab the post and lift it.

Can't say how many inch's but I'd lay plastic on the ground then your straw with plastic on top.

I'd imagine if you went two layers of leafs(leaf=6")staggering the joints should work.

Snow, if we ever get some is going to help.

Eventually you should remove the dirt around the posts or foundation and lay the 2" foam out 4' from the wall or post. Go just below (1')grade at the wall and angled down to 2' below grade 4' out. This would be a good time to get a proper grade away from the building to move water away.

[BobT]

If you’re planning on using straw or hay be prepared to handle the mouse invasion. Just thought I'd throw it out there for you to consider.