Selecting polyurethane spray foam as your insulation is a wise choice as it can help lower your home’s energy costs, but make sure you choose the right product for your climate. Spray foam insulation is available in open-cell and closed-cell configurations, and while most Canadian insulation contractors don’t use the open-cell variety due to incompatibility with the region’s weather, it never hurts to ensure that you’re getting the closed-cell product.
Closed-cell polyurethane spray foam is a very dense material (2 pounds per cubic foot). Its cells are very small and contain a gas that increases the material’s insulating properties. The density of the material allows you to increase the R-value of an area in a way not available with traditional fibreglass batts. A 3 ½ inch exterior wall with fibreglass batts might be limited to a rating of R-12, but this can be increased to R-21 when the fibreglass is replaced with closed-cell polyurethane spray foam insulation.
The density of closed-cell spray foam has a few additional benefits over fibreglass: the product provides a better barrier against water and air intrusion, it stays in place once installed, and it can even add strength to your home’s structure. Closed-cell spray foam is a good choice for attics when used under cellulose insulation and is ideal for below-grade applications where moisture might be a problem. If you’ve ever had a persistent draft due to missing or loose fibreglass batts, spray foam will completely fill the cavities between framing members and put an end to that problem forever.