Most older homes such as mine were built with fiberglass mats as insulation in the walls and attic.   I think many homeowners today have some level of awareness of spray foam. For starters, it can be bio-based or not. Regardless, it is an excellent product because it creates an air seal and is a great vapor barrier. According to Advanced Foam Insulation Co., no other type of insulation creates this seal.

Converting attics into a semi-conditioned space in hot climates by closing soffits, gable and ridge vents is a positive design approach in reducing the moisture loads in houses and buildings. This can be achieved by moving the insulation from the floor of the attic and applying spray foam to the underside of the roof deck to seal all the vents. This is the preferred method by many home builders.  

This design prevents the moisture-laden outside air from entering the attic and subsequently from getting into the living area of houses and buildings. The air seal also prevents the radiant heat from migrating into the living area. The lower humidity levels create indoor air quality that is much more comfortable to live in. This is very important in all higher-humidity climates such as the coastal regions of the United States.

According to Advanced Foam Insulation Co., combining these insulating methods with “Low E” glass in the windows will help to lower utility bills by 40 percent to 60 percent compared to a building that has conventional insulation. Not only is spray foam insulation an excellent thermal and moisture barrier, the indoor air is also much cleaner. Spray foam greatly reduces pollen and dust from entering your home or office building, thus decreasing rates of occurrence for allergies and asthma.

Currently, bio-based spray foam has a small percentage of “bio” and a large amount of “non-bio.” According to the US Environmental Protection Agency (EPA), there are health concerns associated with the non-bio portions of spray foam. Most spray foam formulations contain isocyanates and polyols. According to the EPA, spray foam contains a side A and a side B. For side A, isocyanates are the primary compound of interest and are a class of highly-reactive chemicals with widespread industrial, commercial and retail or consumer applications. Exposure to isocyanates may cause skin, eye and lung irritation, asthma and “sensitization.” Isocyanates are irritants to the mucous membranes of the eyes and gastrointestinal and respiratory tracts. Direct skin contact can also cause marked inflammation. There is no recognized safe level of exposure to isocyanates for sensitized individuals. Isocyanates have been reported to be a leading attributable chemical cause of asthma in the workplace.

Side B contains a blend of proprietary chemicals that provide unique properties in the foam and may vary widely from manufacturer to manufacturer. Amine catalysts in SPF may be sensitizers and irritants that can cause blurry vision, also known as a halo effect.

Flame retardants, such as halogenated compounds, may be persistent, bioaccumulative, and/or toxic chemicals (PBTs). Some examples include:
– TCPP -(Tris(2-chloroisopropyl)phosphate)
– TEP -(Triethyl phosphate)
– TDCP -(Tris (1,3-dichloroisopropyl) phosphate blend)