How to Seal Off Crawlspace Vents

Most local building departments are now not requiring vents.

Pests and insects can get into your crawlspace providing for a inconvenient time in removing them from the crawlspace. Crawlspaces are installed in the foundation of a home to provide ventilation under the house to prevent mildew and rot. You can prevent pests and most insects from getting into your crawlspace if you properly seal the entrance. To properly seal the crawlspace, install a vapor retarder to prevent moisture from rising into the foundation.

Things You'll Need

• Vapor retarder liner
• Staple gun
• Turf staples
• Fiberglass mesh tape

Instructions

1. Lay down the vapor retarder on the soil in the crawlspace. Leave at least 12 inches of vapor retarder overlapping in all areas to allow you to secure it to the wall.

2. Start from one corner of the crawlspace. Staple the liner to the wall around 2 inches from the top with the staple gun. Use only turf staples as they secure the liner the best to the wall. Work your way around the crawlspace, stapling the liner every 6 inches.

3. Tape over the staples and the corners of the vapor retarder liner with the fiberglass mesh tape. This process will provide an airtight seal and not let any moisture leave via the staples.

4. Seal the vent. If the wall is masonry, use bricks to cover the entrance. Lay the bricks and secure them with cement. If the wall is made of wood, cover the entrance with wood siding. The most time-efficient and cost-effective way would be to buy sealed crawlspace vents. You can find or order these products at most large hardware stores.

Tips & Warnings

• If you do not install the vapor retarder liner, you cannot seal a crawlspace. It is required by the building code to install the liner before sealing.

References

• HousingZone: To Vent or Not to Vent
• Ask the Builder: Crawl Space Vents