Choosing the Best Basement and Crawlspace Insulation

August 2, 2019
niki dube

closed cell spray foam insulation basement

When it comes to insulating the ceiling of your basement, crawl space, or elevated home, what is the best insulation to choose: fiberglass, open cell, or closed cell?


You’ve likely heard that spray foams offer the best R-value per square inch, so it’s easy to assume that both open and closed cell offer the same benefits, but that’s a mistake that can lead to costly consequences.

All insulation is not created equal, especially when it comes to subfloors in basements and crawl spaces. Here’s why:

Although they’re both great insulators when used properly, open cell foam and fiberglass can trap moisture within floor systems, causing wood floors to cup, buckle, and stain. When applied to subfloors in crawl spaces and basements, open cell is exposed to humidity, critters, and ground moisture. With these forces combined, long term trouble awaits and insulation efficiency suffers.

As the only insulation approved by FEMA, closed cell is the optimal choice to effectively insulate subfloors. Not only is it waterproof, and a critter inhibitor, it also increases the strength of the building to which it is applied. As a vapor barrier, closed cell creates a seal that prevents air from moving through the insulation and into your home, keeping humidity and moisture out and your conditioned air where it belongs—inside your home!

Before you start your next basement or crawl space project, contact Max Insulation today for a prompt—AND FREE—home energy evaluation.