This seems to be a popular topic and any further advice would be greatly appreciated as I've researched this to death.
I recently purchased a home just outside the Boston, MA area (built in 1966) and I want to add insulation to the attic. I've researched cellulose, spray foam, encapsulated and fiberglass a lot and I've narrowed it down to the cellulose and the spray foam.
I would love to do the foam, but I'm unsure about it's:
1) long-term affects, in other words, does it degrade in any manner that would be hazardous to my family (toxic fumes in later years?) or does it really lose it’s effectiveness over the years? I plan on living here for at least 20 years.
2) being in my 40s, I'm of the generation that believes that it's not a good idea to completely seal off the attic. I'd be spraying the foam on the envelope of the house, sealing all of the gable vents, ridge vents and soffits, creating conditioned space. I’m doing this as I’m going to install a gas-fired boiler in the basement and run a couple of water/glycol lines up into the attic to get heat into the second-floor living area.
3) the issue of moisture and mold possibly building up in the attic. All of my bathroom vents are properly hooked into PVC pipes that vent outside of the attic, but being constantly dark and unventilated with the foam installed, should I worry about this?
4) does foam burn? Might it give off toxic fumes if fire is in the area? All I can think of here is that R.I. nightclub (The Station) that killed 100 people.
If you feel that any of these are real issues, then I have no problems with blowing in cellulose on the attic floor. Though it will be real dusty up there.
Thanx in advance for your time!!!