Is a SPF Roof Right for Your Commercial Building

In today’s building industry, there is a growing desire to provide owners with durable, long-lasting roofing systems that combine high energy performance with low maintenance costs.  Spray Polyurethane Roofing Systems have been around for more than 40 years; however, there is still a significant lack of knowledge among many roofing professionals on how to specify, install, or maintain these systems.

Spray polyurethane foam (SPF) roofing consists of an application of specifically designed foam covered with an acrylic elastomeric coating to protect the foam from ultraviolet rays. SPF has a closed-cell structure that makes it water resistant.

A study by the National Roofing Foundation on over 300 SPF roofing systems in six different climate zones in the United States determined that SPF roofs have an effective service life of more than 30 years.  In 2004, Michelsen Technologies performed a life-cycle analysis for SPF roofing systems in five climate areas of the United States. The study concluded that the average SPF roofing system in those areas cost between 15- and 50-percent less to install and maintain than conventional membrane systems over a 30-year time frame. The study reported costs based on 6-year, 10-year, and 15-year recoat schedules. The research also shows that the physical properties of the foam change very little with age. This indicates that the life expectancy of a SPF roof system depends primarily on the original application and long-term maintenance.  With semi-annual inspections and re-application of the acrylic coating every 15 years a foam roof should be expected to last in excess of 50 years.

SPF roofing systems have good adhesion to a variety of substrates, including metal, wood, concrete, and built-up roofing (BUR). Since SPF adds little weight to existing roof coverings and can build slope to fill in low areas, these systems are used frequently as a recover roofing system.

SPF roofing systems excel when the following conditions exist:

  • Additional insulation is required.
  • There are severe temperatures.
  • The roof substrate has numerous penetrations.
  • The roof deck is an unusual configuration.
  • The roof is in an area where high winds are likely to occur.
  • Lightweight materials are required.
  • Slope must be added to provide positive drainage.
Because of the energy-saving characteristics and low maintenance costs of SPF roof systems, these roofs are suited to companies or organizations that own their own buildings and must pay their own energy and maintenance costs.

In conclusion, SPF systems can provide long-lasting and durable roofing solutions while contributing to a lower environmental impact. However, to be assured of a quality application, a building owner or owner representative should do their homework to understand the roofing system and hire a responsible contractor.

This article is a summarization of an article by Mason Knowles, the executive director of Fairfax, VA-based Spray Polyurethane Foam Alliance (www.sprayfoam.org). 

Wind uplift information

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SPF Proves Its Worth
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