Subfloor Insulation: Which is Best?

When it comes to subfloor insulation, you have three choices: fiberglass, open cell, and closed cell spray foam insulation. All insulation is not created equal, so which is best?

Subfloor Insulation Closed Cell Spray Foam


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. Here’s why:

Although they’re both great insulators, open cell foam and fiberglass can trap moisture within floor systems in humid climates and flood prone areas, causing wood floors to cup, buckle, and stain. When applied to subfloors and crawlspaces, 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 in flood zones. Not only is it waterproof, it also increases the strength of the building to which it is applied. As a vapor barrier, closed cell creates a seal that prevents humid air from moving through the insulation and into your home, keeping humidity and moisture out.

Before you start your next subfloor, basement, or crawl space project, contact the Texas Insulation team today for a prompt—AND FREE—estimate.