Spray foam roofing is also known as Spray Polyurethane Foam (SPF) roofing. It is essentially a liquid plastic which expands up to 30 times its size as it dries. SPF dries within seconds of its application.
Benefits of an SPF Flat Roof
The weakest part of any roof is at its seams. The hugest advantage of spray foam flat roofing is that it is seamless and self-flashing. Rather than using nails and metal strips to apply the material and to waterproof your roof, SPF is simply sprayed on, expanding into every nook and cranny.
SPF roofing is also very lightweight – less than 1 pound per square foot. This is beneficial as it will reduce the stress upon your home.
SPF roofing is long-lasting. If properly applied and maintained, a spray foam flat roof has an indefinite lifespan. Often, an SPF flat roof will be eligible for an extension on the original warranty at the end of the warranty’s period. Spray foam roofing that has sustained heavy damage can also be rejuvenated, reducing the costs of having to replace your roof.
Spray foam roofing can also be applied overtop of an existing flat roof, although this should be discussed with your roofing professional. This will reduce the costs of roof removal and disposal.
SPF is energy efficient and useful as a cool roofing system. This is due to its high insulation properties and high solar reflectivity rating (the amount of heat reflected off of the roof rather than absorbed.) This is partly due to its white coloring, but also due to its seamless nature. It acts as an air barrier, preventing the transfer of energy through the roof.
Spray Foam Roof: Not for a Quick Fix
Although spray foam flat roofing is often used in conjunction with other flat roof systems, it should not be used as a pitched roof undercoating. The waterproof properties that make it perfect for flat roofing makes it a nightmare for shingle, slate or tile roofing. This is for two main reasons, the first being movability. A shingle or tile system is designed to shift and move freely as the roof deck expands and contracts. Shingles and tiles bound to the foam will end up breaking and cracking over time.
The second reason is the reduction in breathability. A pitched roof system is designed to allow air and moisture to escape while keeping water out. A sealed roof will end up rotting your roof deck.
Spray foam roofing should also never be used as a quick fix for your roof, flat or otherwise. It is best to have your flat roof professional evaluate your roof in order to avoid serious and costly problems in the future.