Here in the southeast we have insulated many crawl-space areas under older homes. We will usually install one inch, however, in your location, you would want to have two or more inches installed. In the southeast, the IBC recommends an R-5 value. Urethane foam will give you an R-7 per inch.

Urethane foam is not effected by freezing temperatures. This insulation product is used extensively in Alaska and other sub-zero climates.

To insulate the roof as you have described would be difficult to determine without inspection of the roof structure. If the roof is leaking, one option would be to apply strips to exterior of roof, apply foam between strips and then cover with new metal roof. This application has been very successful on older A-frame model homes that needed a roof and the additional insulation.

I hope this gives you some information to work with. If you have other questions please feel free to contact me.

The house freezes completely for a few months each winter when we close it. All aspects of the house are designed around this. So, while renovating, I decided to use no drywall or latex paint, because drywall crumbles if it freezes like this, and paint eventually peels. What does foam insulation do over repeated freezings?

I am thinking of using spray foam on the main floor’s underside, and everywhere else, but am concerned about two things: fumes, and eventual rot where wood meets foam.

Also, to insulte the roof (cathedral ceiling shape, not very high though – Probably 9 feet from the floor at highest point), I grew up with the mantra to leave some airspace so air flows across the space. If the foam is sprayed directly onto the roof’s wooden interior, this is bad, no? And doesn’t it also just trap any moisture and accelerate woodrot?

Thanks for a speedy reply! I appreciate it very much.

I wouldn’t recommend spraying the underside of the roof unless you are planning on finishing it out as a regular room. The reason is that you want to keep the insulation as close to the area you are trying to control as possible. If you spray the roof, it’s true that the attic wont get as hot as a regular attic during the day, but it also wont let the warm air escape at night.

For instance we will usually spray around 3 inches in a commericial walk in cooler/freezer. This is because the temperature delta from inside to outside is much greater than in a house.

thanks for your info. your web site has been great