SPF Roofing Frequently Asked Questions

How long does a spray polyurethane foam (SPF) roof last?

The oldest performing SPF roofs are over 35 years old. Because the physical properties of the SPF change little with age, how long the SPF roof system lasts depends primarily on the quality of the original application and how well is has been maintained. If the roof has been inspected and recoated as needed the roof should last for the life of the building.

How do you maintain a SPF roof system?

SPF roof systems should be inspected semi-annually and after events that could cause physical damage. Small (less than 3" diameter) dents, cracks, punctures from dropped tools, wind driven debris can be repaired with an elastomeric sealant compatible with the SPF and coating system. More extensive damage can be repaired by reapplying SPF.

Typically SPF roof systems are re-coated every 10 - 15 years, depending on the type and thickness of coating used and factors specific to the roof (such as wind erosion effects, hail, foot traffic, abuse, etc.) Recoating will extends the service life of the SPF roof system for another 10 - 15 years.

Where can I use a SPF roofing system?

SPF has excellent adhesion to a variety of substrates including, BUR, clay and concrete tile, shingles, metal, wood and concrete. Since they add little weight and can be applied in varying thickness to add slope and fill in low areas. SPF roofing systems are often used as recover system over existing roof coverings.

SPF roofing systems excel where:

Additional insulation is desired.
The roof substrate has many penetrations;
The roof deck is an unusual shape or configuration;
The roof is in a severe weather environment, (hurricanes, hail, etc)
Lightweight materials are required.
When slope must be added to provide positive drainage
When it is desirable to keep existing roof covering

What are the environmental limitations of installing SPF roofing systems?

As with other roofing systems, SPF can be applied in a wide variety of climatic conditions. Follow the manufacturer's recommendation for ambient conditions. The SPF and protective coating should not be installed when there is ice, frost, surface moisture or visible dampness present on the surface to be covered. Barriers may be necessary if wind conditions can affect the foam quality or create over-spray problems.

How do SPF roof systems compare in cost to other roof systems?

SPF roofing systems are cost competitive with other systems. Life Cycle Cost Analysis performed by Michelsen Technologies demonstrated that over a 30 year life span, SPF roof systems cost between 10% and 50% less on average than comparably insulated membrane roof systems. (Averages were based on SPF roof system recoats of every 6, 10 and 15 years. A copy of the Life Cycle report is available from SPFA.)

Why do you need coatings or coverings over SPF?

SPF is water resistant without other coverings, however, the surface of SPF can deteriorate under the sun's ultraviolet (UV) rays. Typically, elastomeric coatings or aggregate coverings are used to protect the SPF against UV radiation.

How long has SPF been around?

Spray polyurethane foam was first used commercially in the US in the 1960s for cold storage and industrial insulation projects. SPF roofing systems evolved from exterior applications to tanks and pipes in the late 60s to early 70s.

To learn more about SPF roofing please call us at 201-735-7600 or 914-623-0326.

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