The Expansion of SPF

According to a 2008 study conducted by the Cleveland-based 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 has 10 percent of the market; and spray polyurethane foam, or SPF, makes up a little less than 5 percent, or about $200 million, of the market.

According to the Fairfax, Va.-based Spray Polyurethane Foam Alliance, SPF has one of the highest insulating R-values—up to R-6 per 1-inch thickness—of the available insulation products on the market today. 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 residential applications, 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 for 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 their home.”

There are several types of SPF to choose from. Closed-cell SPF, which is available in low-, medium- or high-density products, contains tiny cells that are packed tightly together and are filled with a gas that makes the foam expand, which provides structural support to a building. The advantages of closed-cell foam include its strength, higher R-value than open cell, and strong resistance to air and water vapor. In open-cell SPF, the cells are not completely closed and expansion occurs as air fills the open space. Open-cell foam, which is only available as a low-density product, requires less material and, therefore, is less expensive.

Choosing a low-, medium- or high-density SPF determines the weight of the product and its R-value. Low-density, open-cell SPF, which weighs between 0.4 to 0.6 pounds per cubic foot, typically uses water as a blowing agent and has an R-value around 3.5 per inch. Medium-density, closed-cell SPF, which weighs between 1 1/2 to 2 pounds per cubic foot, uses a high-R-value blowing agent and achieves an R-value of around 6 per inch. High-density SPF, which weighs 2 pounds per cubic foot, features a high-R-value blowing agent and achieves R-values ranging from 5.5 to 6.5 per inch.

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

In addition, the seamless barrier in all SPF products inhibits growth of mold and bacteria.

“Closed-cell spray foam controls moisture well enough to satisfy current International Code Council requirements without an added interior vapor retarder in most applications,” says Tom Sojak, vice
president of sales for Gaco Western’s WallFoam division, Seattle.

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.