One of the most common questions our clients ask is: "Why do you have to remove the insulation?" And the follow-up: "Do you put it back?" The answers are important — and might change how you think about your crawl space.
Why Insulation Must Be Removed
During mold remediation, we need to see and treat every square inch of wood — the joists, the sub-floor, and every structural element. Batt insulation hides the very surfaces we need to access. But it's not just about access — that insulation has been sitting there collecting moisture, pest activity, and mold spores. It's contaminated, and it cannot be safely reinstalled.
Why You Don't Need Sub-Floor Insulation in Middle Tennessee
This surprises many homeowners, but here's the truth: in Middle Tennessee's climate (classified as Cfa — humid subtropical by the Koppen-Geiger system), sub-floor batt insulation makes virtually no noticeable difference in energy efficiency. Our winters are mild, and the crawl space temperature stays relatively moderate year-round.
Common Problems with Batt Insulation
Gravity causes it to fall and sag over time
Often installed too wide, causing compression and reduced R-value
Gaps, voids, and seams left during installation
Kraft-side (vapor barrier) frequently installed in the wrong direction
Not properly cut around wires, pipes, or HVAC ducts
Staple 'tiger teeth' cause compression points
Holds moisture, creating ideal conditions for mold
Provides nesting material for pests
Alternatives (If You Still Want Insulation)
Option 1: Spray Foam Insulation
Closed-cell spray foam is the preferred option for crawl spaces — it provides a higher R-value per inch and acts as both insulation and a vapor barrier. Open-cell foam is less ideal because it allows moisture to pass through.
Option 2: Rigid Foam Board
More labor-intensive and expensive, but provides an adequate thermal barrier. A viable alternative if spray foam isn't feasible.
Our Recommendation
Instead of replacing batt insulation after remediation, we recommend treating your crawl space as a separate building envelope:
This approach addresses the root cause (uncontrolled moisture) rather than treating the symptom (cold floors). The result is a healthier home with better air quality and no risk of insulation-related mold issues.