Spray foam insulation is an alternative to fiberglass and cellulose, typically used in attics or wall cavities. It seals well to prevent air movement between different parts of the structure and helps reduce heating and cooling costs. Spray foam also helps to keep moisture out of basements, avoiding mildew and mold issues. It can be installed in a variety of areas including basement rim joists, crawl spaces, attics, knee walls and bonus rooms.

This type of insulation is made from 2 types of composite material, polyurethane and isocyanate, which chemically react to expand as they are sprayed. It provides an effective vapor barrier and has higher R-value per inch than fiberglass or cellulose. It is expensive and requires professional installation.

There is no doubt that spray foam is very energy efficient and does a good job of keeping moisture out, however there are other concerns with this product. When it isn’t properly applied, spray foam can cause mold and health problems. It can also off-gas amines and isocyanates into the air, which is a concern for people with asthma or other respiratory conditions. This off-gassing is caused when the chemicals aren’t mixed or sprayed at just the right temperature.

Another major issue with spray foam is that it contains hydrofluorocarbons (HFCs). HFCs have a Global Warming Potential of 3,400 – which means they contribute to climate change more than carbon dioxide does, on a per kilo basis. If you do choose to use this type of insulation, look for brands that use low GWP blowing agents like BASF Walltite CM01 or Genyk Boreal Nature.