Foam Roof Density and R-Value

Density of SPF is important when it comes to strength and Thermal Resistance. Obviously, higher density means increased strength and higher R-value. Most SPF roofs have densities ranging from about 2.5 pounds per cubic foot to 3 pounds per cubic foot.

Three pound density foam has a compressive strength of about 50 psi and an R-value of 7.14 installed and 6.86 aged (these numbers may vary slightly depending on the foam manufacturer.

Because it is sprayed onto the roof as a liquid, it forms a single continuous structure that is seamless and very stable. SPF requires a clean surface for proper application. It must be dry, free of contaminants like oil, and properly fastened to the substrate in accordance with the proper building codes.

SPF's Waterproofing Ability

Sprayed Polyurethane Foam is perfect for many different waterproofing applications. Because it is composed of billions of closed cells, the foam acts as an air barrier, preventing moisture infiltration into the building.

This ability minimizes dew point problems, which unchecked lead to water condensation inside of the structure. Moisture infiltration into the building envelope is the number one cause of building deterioration.

Even when the top coat of a foam roofing system is damaged, the underlying foam will keep the roof from leaking. The Superdome in New Orleans was damaged once in a severe hail storm. Thousands of hairline cracks appeared in the top coat, but no leaks ever occurred, even though it wasn't repaired for over a decade!

If a penetration does occur all the way from the foam layers, the water infiltration will be isolated only to the area where the membrane has been penetrated. Small penetrations in foam roofing systems can be repaired easily with an elastomeric caulk, reinstating the integrity of the system.

Water ponding is quite often a problem with conventional roofing systems. When applying the polyurethane foam in reroofing situations, it is very easy to build up areas of greater thickness while spraying so that water will drain properly. This also eliminates the problem of the additional weight load associated with water accumulation.

What is SPF?

Sprayed Polyurethane Foam is a combination of isocyanate and polyol. These two components are fed through a proportioner which heats then pumps the two separate components to the spray gun, where they are mixed and sprayed onto the substrate.

Because it is sprayed onto the roof as a liquid, it forms a single continuous structure that is seamless and very stable. SPF requires a clean surface for proper application. It must be dry, free of contaminants like oil, and properly fastened to the substrate in accordance with the proper building codes.

A protective elastomeric top coat (Acrylics, Silicones or Polyureas) is required which is typically sprayed on as well, but it is also possible with some to be applied with hand or power rollers.

provides superb energy savings along with a significant reduction in air infiltration, resulting in outstanding long-term value and return on investment.