Flat or low-pitched roofs are typically found in the desert southwest and other arid climates where rainfall and freezing temperatures are rare.
Built from OSB or plywood, flat roofs allow for drainage through scuppers and gutter systems. Commonly used protective barriers or coatings for flat roofs include tar and gravel, fiberglass, rubber, modified bitumens and polyurethane foam.
Most flat roofs in Arizona are sprayed with polyurethane foam for its functionality and energy-efficiency. Foam coverings are waterproof, light, easy to maintain and include an elastomeric material that form a barrier to UV rays.
A flat roof can last for up to 30+ years if properly coated and maintained. However, flat roofs pose unique challenges including the accumulation of leaves and other debris which can clog water outlets, so homeowners should take special care to keep the area clean. Coating is key, so any visible damage such as cracking or blistering should be repaired immediately.