Most older homes, such as mine, were built with fiberglass mats as insulation in the walls and attic. Many homeowners today are aware of spray foam insulation. It can be bio-based or non-bio-based. Regardless, it is an excellent product because it creates an air seal and functions as a high-quality vapor barrier. According to Advanced Foam Insulation Co., no other type of insulation creates this seal.

Creating Semi-Conditioned Attic Spaces

Converting attics into semi-conditioned spaces in hot climates is an effective design strategy for reducing moisture loads in homes and buildings. This is accomplished by closing soffits, gable vents, and ridge vents; moving insulation from the attic floor; and applying spray foam to the underside of the roof deck to seal the vents. This method is preferred by many home builders.

By preventing moisture-laden outside air from entering the attic, this design reduces the movement of heat and humidity into the living space. The air seal also blocks radiant heat from migrating downward. As a result, indoor humidity levels drop, creating more comfortable indoor air quality, especially important in coastal or high-humidity climates.

Energy Efficiency Benefits

According to Advanced Foam Insulation Co., combining spray foam insulation with Low-E windows can reduce utility bills by 40 percent to 60 percent compared to buildings insulated conventionally.

Beyond energy efficiency, spray foam serves as an excellent thermal and moisture barrier. It significantly reduces the infiltration of pollen and dust, improving indoor air quality and decreasing allergy and asthma occurrences.

Chemical Composition and Health Considerations

Bio-based spray foam currently includes only a small percentage of bio-based material and a larger percentage of non-bio components. According to the U.S. Environmental Protection Agency (EPA), some health concerns are associated with these non-bio portions.

Spray foam typically consists of Side A and Side B components.

Side A: Isocyanates

Isocyanates are the primary compounds of interest. They are highly reactive chemicals with industrial, commercial, and consumer applications.

Possible health effects include skin, eye, and lung irritation; asthma; sensitization; irritation of mucous membranes in the eyes, respiratory tract, and gastrointestinal tract; and inflammation from direct skin contact. There is no recognized safe level of isocyanate exposure for sensitized individuals. Isocyanates are recognized as a major chemical cause of workplace-related asthma.

Side B: Proprietary Chemical Blends

Side B contains a blend of proprietary chemicals that vary by manufacturer. Components may include amine catalysts and flame retardants.

Amine Catalysts

Amine catalysts may act as sensitizers and irritants. They can also cause blurry vision, known as the “halo effect.”

Flame Retardants

Some flame retardants may be persistent, bioaccumulative, and/or toxic (PBTs). Examples include:

• TCPP (Tris(2-chloroisopropyl) phosphate)

• TEP (Triethyl phosphate)

• TDCP (Tris(1,3-dichloroisopropyl) phosphate blend)

For More Information

Please click HERE to read our publication Insulating Raised Floors in Hot, Humid Climates. In this study, we evaluated how insulated raised floors influence moisture movement in residential structures and the extent to which they contribute to improved energy efficiency in hot, humid climates.