spray in foam insulation in attic rafters
I am considering having spray in foam insulation installed in our attic rafters. I have a 1950s ranch style home with a low pitched roof. Attic temps can be extreme in the summer months. I live in southeast Texas where the average summer highs can reach 95 degrees with 80-90% humidity.
I have a few questions regarding the effectiveness of this technique. When the foam is sprayed in, should it cover all ventilation effectively making the attic conditioned space? I have read that if spray in insulation is used the attic should be sealed off. I have also heard that this can damage the roof sheathing causing it to rot? The attic is currently vented with soffit vents and ridge vents.
There is also a company that installs spray in radiant barrier. This method would keep the attic ventilated but cuts back on the radiant heat coming in from the underside of the roof sheathing.