Step 2: Foam
Application of Waterproof Polyurethane Foam
Closed cell Spray Polyurethane Foam (SPF) lies at the heart of the Dura-Foam roof system. SPF is a waterproof material that also has a high insulation value of R 6.25 per inch. When exposded to water, this roofing material remains dry because its foam cells are closed and impenetrable by water. A successfull SPF application process requires an experienced crew as well as the right equipment.
How Waterproof Polyurethane Foam Is Made
Two components combine to create waterproof polyurethane foam, isocyanate and resin. These materials travel separately through several controlled stages in expensive state-of-the-art equipment where their temperature and pressure are precisely maintained. The two materials don't combine until they reach the tip of a special spray gun. In essence, the roofing material is being manufactured in-place to form a waterproofing barrier of customized thickness with no joints and no seams. Unlike many of our competitors, we do not pump these materials out of 55 gallon drums. Our trucks carry large reservoirs that ensure temperature stability and material purity resulting in a better product (smooth and 100% waterproof closed cell polyurethane foam).
Our modern trucks contain the best equipment available.
How Polyurethane Foam Is Applied
As the polyurethane foam is sprayed in place, it hits the roof surface as a liquid then rises in three seconds. It can be walked on in one minute. As SPF is sprayed in place, it forms a single monolithic barrier that seals the entire roof surface from edge to edge with no seams or joints. Sealing around difficult roof items such as circular exhaust vents is done easily with SPF. Roof thickness is monitored and low areas are built up to improve drainage. Edges are trimmed for neat appearance. The foam application is a critical step because the closed-cell foam is the primary waterproofing barrier.
Image of an SPF foam roof system in progress.
Thickness of Polyurethane Foam
Foam thickness is typically a minimum of 1" thick on large commercial roofs and 1 1/2" thick on residential roofs. Maximum thickness varies based on drainage and insulation requirements. For example, roof projects requiring R19 insulation on the roof surface generally receive 3.5" of polyurethane foam insulation. Or, a flat roof with a severe low area in the middle could receive 5.5" of foam near the center and taper down to 1" of foam near the edges.
