Fiberglass vs. Spray Foam: Choosing Crawlspace Insulation

The Problem with Fiberglass

Fiberglass insulation is common, but in a crawlspace, it often acts like a sponge. It absorbs moisture, becomes heavy, sags, and eventually becomes a breeding ground for mold.

Rigid Foam: A Better Alternative

Rigid foam board (like EPS or XPS) is moisture-resistant and provides a much more effective thermal break when applied to crawlspace walls.

Spray Foam: The Ultimate Seal

Closed-cell spray foam provides both insulation and an air seal. It’s often the best choice for rim joists and hard-to-reach areas.