The average home has dozens of pest entry points — most invisible from the outside. A ¼-inch gap under a door. A dime-sized opening around a dryer vent. An unsealed weep hole in the brick. Each is a highway for a different set of pests. This guide maps the 15 most exploited entry points, ranked by how many pest species use them, and shows exactly how to seal each one.
1. Gaps around pipe penetrations (kitchen, bath, laundry): The #1 entry point for cockroaches, ants, spiders, and mice. Every pipe through an exterior or foundation wall has a gap around it. Seal with: copper mesh packed tight, sealed over with silicone caulk.
2. Exterior door thresholds: The gap under exterior doors admits mice (¼ inch is enough), cockroaches, spiders, crickets, and earwigs. Seal with: brush or rubber door sweeps on every exterior door including garage entry doors.
3. Foundation cracks: Settling cracks in poured concrete or mortar joints in block foundations allow ants, cockroaches, earwigs, springtails, and termites to enter. Seal with: silicone caulk for hairline cracks, hydraulic cement for larger gaps.
4. Weep holes in brick veneer: Designed for drainage, but open weep holes are mouse, wasp, and cockroach entry points. Seal with: steel wool or copper mesh pushed into the weep hole (maintains drainage while blocking pests), or commercial weep hole covers.
5. Garage door bottom seal: The widest opening on most homes. Cracked, compressed, or missing seals admit everything from mice to snakes. Seal with: replacement rubber bottom seal ($15–30).
6. Window frame gaps: Shrinking caulk around window frames creates entry for stink bugs, Asian lady beetles, cluster flies, and spiders. Seal with: exterior silicone caulk.
7. Dryer vent: Stuck-open flaps or missing pest guards allow mice, wasps, and birds to enter the vent duct. Seal with: louvered vent cover with pest screen, or a dryer vent guard.
8. Where siding meets foundation: A common gap in vinyl and wood siding homes. Seal with: caulk or foam backer rod + caulk for larger gaps.
9. AC line penetrations: The refrigerant line set and condensate drain pass through the wall with a gap sealed by expandable foam — which mice chew through. Seal with: copper mesh around the lines, covered with silicone caulk.
10. Electrical and cable entries: Utility boxes, cable TV lines, and phone wires create small gaps. Seal with: exterior-grade silicone caulk.
11. Soffit vents and gaps: Squirrels, raccoons, bats, and wasps enter through damaged or unscreened soffits. Seal with: ¼-inch hardware cloth over all soffit vents.
12. Ridge vents: Bats enter through gaps in ridge vent installation. Seal with: ridge vent baffles or hardware cloth.
13. Chimney: Unscreened chimneys admit raccoons, squirrels, birds, and bats. Seal with: wildlife-rated chimney cap with mesh screen.
14. Roof-wall junctions: Where a lower roof meets a wall — construction gaps here admit squirrels and roof rats. Seal with: flashing + caulk or hardware cloth.
15. Torn window screens: The simplest entry point for flies, mosquitoes, wasps, and stink bugs. Fix with: screen patch kits ($5) or full screen replacement.