I'm interested in hearing opinions (especially fact-based opinions) on the long-term safety and efficacy of foam insulation.

I love the idea of the foam insulation. It seems it would insulate my 2x4 exterior walls better than any of the alternatives. I am, however, worried that "they" will discover something bad about foam insulation 10..20 years down the road--something that could greatly depreciate the value of my home. I'm also worried about the safety of the stuff in case of a house fire. I've talked to some spray foam installers and they talk about the shield that the drywall provides, but I'm still not convinced. I've smelled a small amount of plastic burning and it's pretty noxious. I'd imagine if an entire wall filled with foam were burning, the fumes could likely knock a person out.

And, what about moisture? Could it be that foam is "too good" at blocking moisture? For example, if my exterior wall cavities are filled with foam, what happens to the moisture that wants to travel toward the out-of-doors? Could it cling to the drywall backer?

Also, it's very expensive to have a contractor install spray foam and I don't have the same resources as Mike Holmes, so I'd likely do it myself using a product like FoamItGreen. Does that seem reasonable, or would I be installing an inferior product to the one installed by the pros?

Thanks in advance.

This message has been edited. Last edited by: SturdyNail,

I'll only comment on the DIY part of your question.
Unless it just one very small area forget doing it DIY.
It's a messy and would require way to much equipment and know how to do it right. What you do not see most often when there doing those shows is the huge truck and all the hoses needed hoses out in the yard.

Truly the future of insulation, in my humble opinion. Time is money in construction.

burning carpet and furniture is going to take you down long before the foam in the exterior walls does. all plastics burn with deadly offgassing, and almost all fires start in the living area, not in the walls or ceiling.

Go with Icynene. It doesn't Out Gas and it's water/soy base. My clients have been using it for years. Other types of foam might out gas causing irritant reactions.

Thanks for your replies 'joecaption', 'CommonwealthSparky', 'swschrad', and 'Jerry Karlo'.

Joe, you mention the "huge truck and all the hoses" that the pros use. The DIY kits sold by TigerFoam and SprayFoamDirect seem pretty manageable though. Are those kits more difficult to use than they appear to be or do they produce an inferior product from the pros?

Also, I do see your point about the mess. That's not as much of a concern for me though, since I will be insulating from the outdoors (I'm replacing the sheathing, so the wall cavities will be open).

Thanks again.

If you're replacing the sheathing, and the wall cavities are gonna be wide open, why not just use extruded polystyrene foam like "Roofmate" to fill those spaces? Just cut the 3 1/2 inch thick slab to slightly undersize with a hand saw, push in two shims on each side to hold it securely in place while you inject "Great Stuff" expanding foam around the polystyrene for a permanent hold.

That's what I'd do, expensive tho the extruded polystyrene is. It's an investment in your house cuz any future owner is gonna be happy to pay extra for 3 1/2 inches of extruded polystyrene at R 5.5 per inch compared to 3 1/2 inches of fiberglass at R 3.5 per inch. That's 60 percent more insulation!


That's your game plan.

This message has been edited. Last edited by: Nestor,

I've had foam insulation in my last two homes. I'll NEVER have anything else, unless they come along with something superior to foam. But it's not likely in my lifetime.

Yes, it costs more, but the payback will be sooner than you think given rising energy prices. We live in SC, and all of my neighbors AC bills are running $300-400/month for the past 4-5 months. Our biggest bill was $178, and we have twice the sq ft they do.

Also, it will make your house VERY quiet. We never hear a car go by on the street. A Harley? Yes, but not cars.

Because the foam seals all the cracks and seams in the walls, there is no need for a vapor barrier as the foam doubles as one.

I'm not a fan of foaming the roof. IMO its not needed, and it adds way too much to the cost with little, if any benefit. I use R-50 blown fiberglass in the ceiling. I understand some installers will foam your ceiling, which I would do. My guy wouldn't do it, because he thought he could convince me to foam the rafters. He lost.

DIY will cost you a fortune due to the cost per foot do DIY kits. And it's not as easy as you think to get the right coverage without a ton of waste.

Ain't nature unfair.

In South Carolina they're paying $300 to $400 per month for air conditioning in summer, and in Manitoba we're paying $300 to $400 per month for heat in winter.

If only we could exchange South Carolina's heat in summer for Manitoba's cold in winter...

This message has been edited. Last edited by: Nestor,

I know of people who've designed their homes to be properly insulated and were glad they did. The difference in energy bill savings were tremendous compared to, say, a neighbor who decided against it to save money on the construction.

Heating and repair can do only so much in terms of your HVAC equipment working properly. If your home is well insulated, then that helps your heating and air costs as well as comfort tremendously. www.aircomfortsolutions.net

This message has been edited. Last edited by: writerlilly,

We had our kitchen wall foamed. Better R-value and the foam itself offers a lot of extra strength to your walls. One thing though, once you foam, don't plan on redoing a lot of electrical very easily - it is sealed in there pretty good. Had our wiring all redone professionally in the walls, so this was not a concern.