A. John Carroll, a mason and builder in Durham, N.C., responds: I've never worried about pests getting in the weeps, because I've never heard of it being a problem. In the Southeast where I build, termites would be the main concern. However, weeps are typically installed well above grade for good drainage, while termites tend to go for a protected route, usually from under the house. If for some reason they were attacking the house via the weeps, there would be visible termite tunnels leading up the side of the foundation, which could easily be addressed.
The weeps lead to an air space between the frame and the house, which doesn't seem to me to be an attractive environment for most common pests, especially if everything is built properly and it's dry. I'm told that mice can squeeze through 1/4-inch-diameter openings (weep holes by code must be at least 3/16 inch in diameter), but usually they're...
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