Polystyrene insulation (Grape Boxes...)

[texican]

Our local grocery store goes through dozens of the white styrofoam type grape boxes. I asked for some, thinking I might insulate some brooder boxes or something with them. Noticed on the back, the Recycling #6.... googled it, and found out they're polystyrene. It's the same stuff as the insulation board used in home construction.

I'm contemplating using it for insulation between my footers and slab. I've got to do more research to see how it would stand up as an insulation layer inside a rock wall. (Don't know whether I want a solid thermal mass wall, or stone/insulation/wood wall, or a stone/insulation/stone wall.)

The only negative I've seen so far is the flammability issue. I wonder if the commercial stuff is any better/worse. What I've seen in the construction stores doesn't seem to have any fireproof backing on it. I did a test yesterday with a piece of the polystyrene... set a piece in a burn barrel... it slowly started burning, and then whoop whoop whoop made a big ol nasty hot fire...

Anyone used polystyrene? Aren't SIP's insulated with polystyrene? SIP's usually have wood on one side, and covered with gypsum board on the other.

The idea of free insulation (with a little carving of the boxes ) is intriguing...

[swampgirl]

Many, many yrs. ago I used it to insulate an old wood shed. Think it helped lower the inside temp some, but the roaches just loved it. It got real gross, so I tore it up. Don't think it should be anywhere near a little chick or animal that could peck at it.

[Toads tool]

I'd use them on the footers before I used them on chickens.

Fill them up and stack them then
If woried about flamability, cover them with a mesh stucco combo. Later on.

I'd think that incorporating styrofome in a sandwich would be better that a solid stone wall any day.

Thay make great worm farms.