Building Envelope

Q: What is spray polyurethane foam insulation?

A:  Spray polyurethane foam (or “SPF” or “spray foam”) is a rigid foam plastic that can be used for insulation in walls and attics, under roof decks, and on roofs and exterior walls. It air seals around walls, roofs and corners, and on contoured surfaces.

Q: How does SPF reduce energy use in buildings?


  • SPF provides a continuous air barrier.

  • SPF prevents moisture infiltration through air leakage.

  • SPF minimizes dew point problems and condensation.

  • SPF avoids thermal bridging.

  • SPF resists heat movement in all directions.

  • SPF provides reliable performance under varying conditions.

Q: Is Spray Polyurethane foam insulation a good investment into my home?

A: As with any energy efficiency home improvement project, you should consider not only the upfront cost of SPF, but the future savings on energy bills. SPF can help lower energy bills by reducing air leaks and improving a home’s energy efficiency by decreasing the transfer of heat between the indoor and outdoor environments. The average payback period for SPF can vary greatly depending on the home, your energy usage, the environment and other factors.

Q: What makes spray polyurethane foam insulation unique?

A: SPF adheres to the wall, forming a continuous insulation and air barrier on the surfaces and cavities to which it is applied even contoured surfaces. SPFs properties as an air barrier make it unique because a separate air barrier does not have to be installed separately as an additional step in the retrofit or construction process.

Q: How does spray polyurethane foam improve my home’s energy efficiency?

A: SPF resists heat transfer extremely well, helping you keep hot air out during the summer and warm air in during the winter. R-values measure the thermal resistance of insulation and open-cell foam, closed-cell foam and roofing foam can all provide high R-values and act as effective insulations. Higher R-values mean that the material is more resistant to heat passing through it, making the material a better insulator. Open-cell SPF typically has an R-value between R-3 and R-4 per inch, and closed-cell SPF typically has an R-value between R-6 and R-7 per inch. R-values are often listed at 1-inch depth for ease of comparing insulation products. To find out the R-value for a specific insulation, refer to the product’s label or technical data sheets, often available online. R-value also determines how thickly a product must be applied to meet insulation needs.

Q: Where can spray polyurethane foam be used?

A: SPF can serve as insulation on the interior of a home or building, in walls, ceiling and attics. It can be applied around corners and on all contoured surfaces. In some regions of the United States, homes with low-slope or flat roofs can use high-density SPF as a roofing material, or as a replacement for insulating sheathing, to provide high protection against heat and water infiltration. SPF can also strengthen the entire structure to which it is applied and increase a building’s resistance to wind uplift.

Q: How long will spray polyurethane foam last/be effective?

A: SPF resists settling, structural deterioration and decomposition over time. In most wall and roof cavity applications, SPF should last the lifetime of the building. Ask your contractor for more information about the expected lifespan of the SPF being installed in your home or on your roof.

Q: Will there be odors during installation?

A: Just like other home projects, installing SPF can cause odors for a limited period of time. When having SPF installed, talk to your professional contractor about the product’s curing time and safety practices. During installation, homeowners, their children and pets leave the home or building. Your professional contractor wears personal protective equipment during and immediately following the application of the product. According to the U.S. Environmental Protection Agency (EPA), after SPF cures, it is considered to be relatively inert, which means the chemicals are finished reacting.

Q: Can I be in the house when spray polyurethane foam is installed?

A: Homeowners, their children and pets leave the home during the installation process. There are a number of variables that affect for how long to leave the home including temperature, humidity levels and the SPFs formula. Homeowners should discuss the amount of time they need to wait before reentering their home with their contractor.

Q: Can spray polyurethane foam make my house quieter?

A: SPF can help minimize airborne sound transmission. Open-cell foam can reduce high-frequency noise and closed-cell foam can reduce low-frequency noise. A combination of open- and closed-cell foams can help maximize noise reduction. It is important to keep in mind that proper sound control involves specific design elements and construction techniques, including layering of materials to achieve desired performance, not just the use of specific products.


Roofing System

Q: What is spray polyurethane foam roofing?

A: Like spray polyurethane foam (SPF) insulation, SPF roofing is very similar to closed-cell SPF insulation, but it has a higher average density and is thus more rigid. It is created in the same manner as high-pressure SPF insulation by mixing liquid chemicals on the job site to create a high-density foam that is impervious to water, allowing it to serve as a very effective roofing material. In some regions of the United States, homes with low-slope or flat roofs can use SPF to improve the home’s air seal and lower heating and cooling energy usage. SPF roofing provides high protection against heat infiltration, strengthens the entire structure to which it is applied and can increase a building’s resistance to wind uplift.

Q: How long does a spray polyurethane foam roof last?

A: The oldest performing SPF roofs are over 30 years old. Because the physical properties of the SPF change little with age, how long the SPF roof system lasts depends primarily on the original application and long term maintenance.

Q: How do you maintain a SPF roof system?

A: 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 SPOF 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 extends the service life of the SPF roof system.

Q: Where can I use a SPF roofing system?

A: SPF has excellent adhesion to a variety of substrates including, BIR, 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 penetration;

  • The roof deck is an unusual shape or configuration;

  • The roof is in a severe weather environment, (hurricanes, hail, etc)

  • Lightweight materials are required.

  • Slope must be added to provide positive drainage

  • It is desirable to keep existing roof covering.