On a recent episode of Ask TOH you were recommending spray-up open cell foam insulation as a remedy to ice damming. This is probably an effective remedy in the snow bound north, but my question is what happens if this approach was tried in the south where we have blistering heat all summer ? It is known that an attic that is not properly ventilated will cause the shingles on the roof to curl up and shorten the life of the roof. With the open cell spray up insulation the heat is trapped between the insulation and shingles wouldn't that affect the life of the roofing material ? Is this open cell spray up even recommended where the summers are hot ?
Paul J. Daoust