Rodents entering through weep holes in Asbury Park, NJ
Recently, a Cowleys home improvement crew was sent to a home in Asbury Park, NJ to perform rodent exclusion work around the home’s exterior foundation. We were asked to perform a weep hole exclusion by installing metal screening over the home’s weep holes (often called just “weeps”) to prevent mice and other rodents from gaining entry.
Homes with exterior brick veneer (thin stone over wood framing) have small openings periodically spaced in the brickwork. This isn’t because the brick mason was sloppy! These holes were left there on purpose. Why? Brick (and stone for the matter) is not waterproof. It’s a highly porous material that acts almost like a sponge and when it rains, the masonry wall absorbs a tremendous amount of water. In order to prevent rainwater from entering the building, masonry construction requires a drainage cavity that allows water to drain down the back face of the brick. The potentially damaging water is collected at the base of the wall by flashing, which is then channeled out to the exterior through these little holes, which are typically about a half-inch wide. Weep holes not only provide an opening allowing water to drain out through the wall’s bottom, but also allow ventilating air to enter behind the wall that helps to dry the structure. Moisture buildup in the cavity can cause mold, mildew, wood rot. If you look carefully, you’ll find these weep holes, a building code requirement, spaced about two feet apart along of the length of the wall. With this Fair Haven home, the entire home exterior was brick, so these gaps surrounded all sides of the house.
Although weep holes are essential for water drainage and ventilation, they have a downside for homeowners. These holes are enticing entry points for mice, other rodents, and even on occasion, snakes, to enter the home. However, for this homeowner with the screening we installed, the wall will still be able to drain and breathe, but now rodents and other pests will no longer be able to use these openings to gain entry.