Spray Foam 101: What you need to know

Spray Polyurethane Foam insulation is a method of sealing and insulating that is sprayed in liquid form into wall cavities, attics, crawlspaces and other areas.  It acts as both insulation and as an air barrier, preventing drafts from entering the building.  The Canadian Urethane Foam Contractors Association (CUFCA) says, when properly installed, spray foam insulation is airtight, and can reduce heating and cooling costs by up to 50 per cent. 

Spray Polyurethane Foam is made when two sets of chemicals contained in separate vats, known as Side A and Side B, are combined together and mixed on site during installation.  Exposure to isocyanates, the chemicals in Side A, is widely known to be hazardous to human health according to the Environmental Protection Agency (EPA), potentially causing respiratory issues and other health problems.

Sprayers are required to wear protective gear, including respiratory masks which supply fresh air and shield their lungs from the fumes.

The proper installation of spray polyurethane foam insulation is difficult: the chemical compounds need to be mixed and applied at the right temperature, in the correct ratio, with a clean gun and hose, and should be applied by a trained, certified and licensed installer.  During and after installation, the premises must be exhaust ventilated - meaning that fans and other equipment must divert the spray-laden air outside the building.

Once the foam has fully expanded and dried, manufacturers say it is inert. The chemicals should have stabilized.

But if the chemicals are not properly mixed, they may not “cure” or react properly.  Improper installation can result in a number of problems, including foam that is too thick or cracks, or emits offensive odours that may or may not dissipate.

Some in the the spray foam industry acknowledge that, although rare, improperly installed spray foam needs to be removed.  

There are currently no industry standards or guidelines guiding the removal of bad spray foam insulation, though the industry is working on developing protocols.

For more, see Is Spray Foam Safe?