Other than cost is there any downsides to Foam Insulation in wal

[Lavndrgrl]

walls? DH and I live in the deep south of the MS gulfcoast. We are redoing a house due to Katrina and want to put in foam insulation into the walls. We are looking towards something like soy based product. Any thoughts.

Thanks,
LG

[T-Bone 369]

Realy no. There are some that talk about off-gassing but in the houses we have built it has not been noticable. It's also a real pain in the backside to run wire or plumbing once it is in the wall so make sure it is 100% done first. If it is installed too thick it will hollow out and crack leaving a void - pro installers know to apply in layers in areas that need it. It will stick to everything so cover anything you do not want it on - again installers are pretty good about that. Foam will seal everything up nice and tight - have actually seen it come out through an exterior wall where there was a small (think pencil sized) hole - so much so that it is often recomended that a fresh air exchanger is used.

We have gotten to the point that we will always try to talk the homeowner into spray foam and geothermal heat/AC - the cost is more but they pay off in just a couple of years. Then it's money in the bank. Don't stop with the walls for the best results - spray the box sill and the attic also.

[Ross]

It is terrific stuff by all acounts, the soy based version having the best vapour barrier properties of them all. I think the only downside is it burns very quickly in a house fire, where Roxel or fibreglass (yuk) do much better. I'd use the soy based spray foam without hesitation if cost were no object.

[Darren]

Any foam will work. If a fire or building inspector sees the foam and whether it's the sprayed on or sheet foam, you may or may not have a problem depending on whether the foam meets code. Either sheet or sprayed on foam comes in varieties with different "fire ratings." The real term isn't fire rating but that will do. Some foams are not acceptable for interior use. A soy based foam may work. I'd wonder if something won't find it tasty.

A lot revolves around whether you are subject to a building code and which codes and standards have been adopted. If no one has to sign off on your house for an occupancy permit, you're free to do what you want.

[ET1 SS]

I used spray-on foam in our house.

I love it.

I sticks to everything, and in seconds it becomes structural. Very hard, sound deadening, and it is great for sealing the drafts.