Last edited by maptax1; 10-20-2011 at 04:02 PM.
The definitve answer would come from your local building department.
However, if you have ductwork and /or HVAC equipment in the attic then having open ventilation is counter productive for the equipment. Having that space at the same temperature as the outside greatly taxes the HVAC syatem.
Personally I would choose closed cell foam sprayed to all surfaces ( underside of the roof , gable walls , floors ) of the attic with no vents. You will create a conditioned space that would be more temperature regulated and easier on the HVAC system.
"" an ounce of perception -- a pound of obscure "
I did the closed cell foam about 2 years ago and it's one of the best things that I've done with my house. I totally agree with everything that CANUK wrote and I'll add that...
1) It paid for itself the the first winter that I had it installed, here in Boston. $3400 was the cost. $2000 back in rebates and we saved a little bit more than the $1400 difference that winter. And later that summer, the house was noticeably cooler as the attic never got that hot.
2) Soundproofing. I live about 5 miles from an airport and when the windows and doors are closed in the late fall, winter and early spring here, its MUCH more quiet. I don't feel the vibrations from those 'low-flyers'. And the house feels more solid.
And lastly, I'm going to foam my basement in a few weeks with the same stuff.
Seal it up and move on to your next project - vf
all attics that are not encapsulated or heated have severe temp changes depending on the season. Have you considered installing an whole house attic fan or more roof venting like a continuous ridge cap vent and more soffit vents? Might check out installing ATTIC FOIL atticfoil.com its real cheap and easy to install and helps bunches
This is a great choice if you have small areas that you need filled.Instead of attempting to push loose insulation into these areas it can be sprayed in.
The foam hardens and supplies insulating qualities to the areas where it has been applied
Greentech for all your Hidden Content , dry lining needs
Small point here. Foam is better for thermal insulation but NOT for acoustic. Foam is too dense, and will couple the two outer surfaces of the wall.
Keeping it Quiet