Inspect the crawl space for moisture, mold, pests, and structural damage
Seal air leaks around vents, pipes, ducts, and wiring penetrations
Repair any water intrusion before insulating
Install a ground vapor barrier over the soil
Overlap vapor barrier seams and tape them securely
Extend the vapor barrier up the foundation walls
Choose the insulation type based on the crawl space condition
Use rigid foam board on crawl space walls when insulating the crawl space perimeter
Cut rigid foam boards to fit tightly against the walls
Seal foam board seams with compatible tape or spray foam
Fasten rigid foam boards securely to the walls
Use spray foam to insulate rim joists and hard-to-reach gaps
Avoid insulating damp surfaces
Do not cover vents unless converting to a sealed crawl space system
Insulate and seal the crawl space access door
Protect insulation from pests and physical damage where needed
Maintain proper drainage around the foundation
Ensure gutters and downspouts direct water away from the house
Check local building codes before starting
Consider hiring a professional for severe moisture or structural issues