Best Insulation Materials for a Crawl Space


High Performing, Rigid foam insulation is perfect for crawl spaces and the walls of the basement. The R-value is very high and is effective at stopping the drafts and good at stopping mold and moisture.

Most people don’t imagine that a crawl space having a big impact on you home. It is also difficult to get to. For this reason people ignore the crawlspace when accounting for energy efficiency and costs.

Don’t catch a cold

The signs of poor crawl space insulation include cold floors, which can weaken your immune system. Another symptom is musty odors that come from below. In fact, if the wrong materials are used mold and mildew will grow in the moist crawl space.

Foam over Fiberglass

In the old days, fiberglass batts would be placed between the joists in the crawl space. Fiberglass was and still is cheaper than other kinds of insulation and more widely available. However, it will absorb moisture, is mold-friendly, and also a nest for mice. It sags and falls out of place too.

Rigid foam is a much better solution. The foam boards is installed against the foundation walls, and unlike fiberglass, it doesn’t absorb water or support bold. It also will not allow air to pass through, if the joints are sealed with tape.


Air Sealing Along with Insulation

Rigid foam insulation is an option for all correct insulation plans in the crawl space. To complete air-seal or “encapsulate”, the rim joists around the foundation must be sealed. Walls are sealed with the rigid foam and dirt-floors are covered with a durable plastic membrane, to reduce moisture levels with waterproofing and dehumidification. These change the area into a clean, dry durable space and leads to comfort and savings inside the home.



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