Expansion of Spray Polyurethane Foam

According to a 2008 study conducted by The Freedonia Group, the U.S. construction-insulation-materials market is expected to exceed $11 billion in 2012. Fiberglass controls approximately 85 percent of the U.S. home insulation market, cellulose is 10 percent, and spray polyurethane foam, or SPF, is a little less than 5 percent — $200 million.

According to the Fairfax, Va.-based Spray Polyurethane Foam Alliance, SPF has one of the highest insulating R-values — up to 6.0 per 1-in. thickness — of the available insulation products on the market. SPF insulation also provides an air barrier, which protects homes from moisture, pollutants and pests. These factors combined with sustainability aspects and safety features deliver an impressive future for the SPF insulation industry.

What Is It?

SPF insulation is a two-component system, consisting of an A side and a B side. The A side is a petroleum-based polymeric isocyanate. The B side is a blend of polyols (the building blocks of foam), blowing agents, flame retardants, surfactants and catalysts. The two sides together create the foam. In a residential application, the product can be used in walls, floors, unvented and vented attics, basements and ceilings.

“Portable and disposable SPF systems require no outside source of power to use them,” explains Mark Wojtiuk, general manager, RHH Foam Systems Inc., New Berlin, Wis. “They are designed such that the chemical reaction between the two components causes them to expand and create the final SPF product.”

“Spray foam is sprayed in as a liquid that quickly expands multiple times in size to fill cracks and gaps,” says Jennifer Wilson, brand manager for BioBased Technologies, Fayetteville, Ark. “This seals the structure, and a sealed thermal envelope allows building occupants to efficiently and effectively condition the air inside a home.”

Low density, open-cell SPF weighs between 0.4 to 0.6 lbs per cu. ft., typically uses water as a blowing agent and has an R-value around 3.5 per in. Medium density, closed-cell SPF usually weighs between 1.5 to 2 lbs. per cu. ft., uses a high R-value blowing agent and has an R-value of around 6.0 per in. High-density SPF weighs 2 lbs. per cu. ft. with R-values ranging from 5.5 to 6.5 per in. and also uses a high R-value blowing agent.

Despite SPF’s benefits, some homeowners run into sticker shock when they initially compare SPF to more traditional insulation systems, which can cost three to four times less.

In addition, spray foam’s seamless barrier inhibits growth of mold and bacteria. “Closed-cell spray foam controls moisture well enough to satisfy current International Code Council [Washington, D.C.] requirements without an added interior vapor retarder in most applications,” says Tom Sojak, vice president of sales, Gaco Western’s WallFoam division, Seattle. “It also offers significant structural value.”

Due to its inherent strength, closed-cell SPF will structurally reinforce the insulated area. It contains tiny cells that are packed tightly together and are filled with a gas that makes the foam expand. In open-cell SPF, the cells are not completely closed and expansion occurs as air fills the open space. The advantages of closed-cell foam include its strength, higher R-value, and strong resistance to air and water vapor. On the other hand, open-cell foam is not as dense so it requires less material and therefore is less expensive.

All SPFs significantly reduce sound transmission by sealing cracks and gaps, thereby preventing sound to travel through the walls, floors and ceilings. Since high-density, closed-cell SPF rigidly adheres to both the exterior sheathing and the studs, it can also deaden the sound caused by vibrations and strong winds.

Homeowner Interest

SPF addresses consumers’ top-of-mind issues, including home comfort and energy efficiency. The effective air seal created by SPF reduces energy loss and moisture penetration, as well as limits entrance of outdoor allergens and pollutants that can affect the comfort of a home.

“The growing trends in the marketplace around more energy-efficient and greener buildings have created an emphasis on controlling the air leakage of buildings, in addition to ensuring a well-insulated building enclosure,” says Chad Fenbert, account business development manager for Owens Corning, Toledo, Ohio. “Homeowners and builders are much more educated about the importance of comfort. It’s not just turning the thermometer up or down; rather, they want to focus on controlling potential leaks from the start.”

“Spray foam insulation has experienced continued growth in the market, even in a down economy, because of interest in green building and energy efficiency,” Wilson adds. “We’ve seen interest in the product for retrofits and new construction. It is an efficient product that will pay off for building owners and for the environment in the long run because of the amount of energy it saves.”

Despite SPF’s benefits, some homeowners run into sticker shock when they initially compare SPF to more traditional insulation systems, which can cost three to four times less. Homeowners can receive as much as a 50 percent savings in their heating and cooling costs when they use spray foam with other responsible building practices, such as thermally efficient doors and windows, good air sealing and right-sized HVAC equipment.

“The highest and quickest return for spray foam is in [extreme] cold and hot climates,” Sojak notes. “The product will still provide a return on investment in more mild, temperate climates but within a slower time frame.”

To minimize upfront costs, hybrid insulation systems that incorporate SPF and fiberglass insulation have become an emerging trend. “Although a whole-house application of spray foam can bring the highest R-value, it can be too costly for some homeowners and/or construction projects,” says Lionel Rossignol, product manager, CertaSpray by CertainTeed, Valley Forge, Pa. “Hybrid systems offer some of the best value propositions available for home insulation by combining the air-sealing characteristics of foam insulation with the time-proven performance and lower cost of fiberglass insulation.”

Considerations

Several SPF products have been made more sustainable by adding bio-content to replace the petroleum-based products used on the B side. Some manufacturers have replaced chemical blowing agents with water and
others seek third-party certifications for indoor air quality, such as Atlanta-based GreenGuard and San Francisco-based Collaborative for High Performance Schools. All SPF products contribute to LEED and NAHB Green points.

Because SPF insulation provides a tighter building envelope, builders, contractors and architects must design and construct buildings where SPF is installed. This allows for plenty of air exchanges to minimize the moisture build-up within the building.

In recent years, rumors have spread about SPF’s combustibility. Many manufacturers offer Class I fire ratings, according to ASTM E84, “Standard Test Method for Surface Burning Characteristics of Building Materials.”

Additionally, products that pass ICC-ES AC377 Appendix X do not require an ignition barrier or intumescent coating when used in unoccupied attics and crawl spaces.

SPF’s chemicals can be temperature sensitive so its chemical temperature should be between 60 and 80 degrees. If the chemical is too warm or cold, the system will not create the best foam product.

Check with the product’s manufacturer for safety procedures, application methods, product information, codes and compliance. “With any foam, safety and awareness are paramount,” Sojak explains. “Contractors should ensure they are always using a professional installer and that proper personal-protective equipment is in place.”

It is important that contractors are fully trained on proper installation practices and safety procedures. Material safety and technical data sheets should be available at every jobsite.

Continued Growth

SPF products are gaining in market share in both residential and commercial construction and it looks like this trend will continue, according to manufacturers. “As codes change, air-barrier codes will dictate the use of air barriers within residential construction,” Sojak predicts. “We’re already seeing this with codes for 2011. With future code changes, it seems that spray foam will become the product of choice.”

Article Resources

BioBased Technologies: Type #65 in E-Inquiry Form
Gaco Western: Type #66 in E-Inquiry Form
Owens Corning: Type #67 in E-Inquiry Form
RHH Foam Systems: Type #68 in E-Inquiry Form

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