Spray foam roofing is ideal for metal buildings because it resolves two major problems almost all metal buildings experience: ice-damming and condensation. This is particularly true with metal frame buildings that have fiberglass roll insulation draped over the beams and purlins with the exterior metal roofing and cladding then screwed through the insulation to the frame.
Where the insulation is compressed against the framing members under the cladding, there is virtually no insulating value. Heat from the building melts the snow on these areas, and when the water runs down the roof to the edge (or another area where there’s less heat loss) the water freezes, causing ice-damming. As the water backs up behind the ice, it works its way through seams and screws holes and the roof leaks.
Also, water vapor that works its way through the vapour barrier layer of the roll insulation finds itself trapped against the cool roof deck, forming condensation. This condensation problem is often mistaken for roof leaks.
A spray foam roof solves both these problems and gives added benefits:
- The insulating foam layer stops heat loss, so ice-damming is eliminated.
- The foam insulation keeps the underside of the roof deck warm, so that escaping vapour can’t condense.
- The roof is completely waterproofed, eliminating problems with leaking joints or screw holes.
- Heating and cooling bills are lowered because of the added insulation.