How to Seal Outside Crawl Space Walls

Inspect all corners inside the crawlspace with light from a flashlight. Some cracks aren't visible from the outside a home. Turn off the flashlight, and check the crawlspace for traces of outdoor light shining into the space. Make a note of the cracks.

Walk outside the home, and seal the cracks you found by filling them from the crawlspace's exterior with caulk or another sealant.

Cover crawlspace exterior wall cracks with weatherstripping. Begin by measuring the crack or area you want to cover. Roll out weatherstripping, and cut it to that measurement. Remove the weatherstripping's adhesive backing, and apply the strip over the crack or area. Press the strip against the wall to ensure it adheres to the surface. Repeat the procedure to cover other portions of the crawlspace's exterior wall with weatherstripping.