10/20/2016

2 Ways to Promote Indoor Air Quality When Installing Spray Foam

In a growing trend, many homeowners are having their homes insulated using spray foam insulation. Spray polyurethane foam is being widely used across the United States to create an air barrier. Although this can greatly improve the energy performance of a home, it creates indoor air quality issues in some homes because stale air gets stuck inside of the home promoting the chance for mold to grow or pollutants to circulate.

Create a Ventilation Strategy

Leaks in the home envelope provide ventilation, but spray foam insulation may seal up these cracks and gaps. Installing spray foam insulation may cause the residence to need a new ventilation strategy to ensure high indoor air quality. Without proper ventilation, indoor air pollutants and moisture from cooking and bathing can get trapped in the home.

For example, bathroom exhaust fans may not function properly if there isn’t enough air flowing into the home to balance the air being exhausted from the home. Air sealing a home may fundamentally change how the house performs, making a balanced ventilation system a great whole-house solution. Zehnder heat recovery ventilators and energy recovery ventilators exhaust and supply an equal amount of air without relying on gaps and cracks in the building envelope to supply air.

In most homes with an energy recovery ventilator or heat recovery ventilator, air is exhausted from the kitchen and bathrooms, and a constant supply of fresh, filtered air enters the bedrooms and living spaces. This allows moisture from indoor activities to be removed, avoiding mold growth. It also dilutes indoor pollutants, which then promotes air quality. All incoming air is filtered, removing dust, pollen, and other airborne contaminants. Zehnder systems are up to 95% efficient in transferring heat from the exhaust air to the intake air, saving energy.

Hire an Experienced Home Performance Company

Spray polyurethane foam is applied as two liquid components from two bottles. One typically contains methylene diphenyl diisocyanate (MDI) and polymeric methylene diphenyl diisocyanate (pMDI). The other is commonly a blend of polyols, catalysts, a blowing agent, a flame retardant, and a surfactant. The liquids from the two bottles are mixed during the application process. Fumes during the installation can be harmful, requiring insulation technicians to wear respirators, and occupants are typically advised to leave the home.

The proper mixture of the two liquids, the temperature during application, and the thickness of the foam are essential for the desired outcome. Errors are more common with inexperienced and poorly trained installers. Fumes and odors from applying the spray foam insulation typically dissipate within a few hours to a few days. If an odor persists after a few days, there may be an issue with the spray foam installation.

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