Summer Exterior Pest-Proofing: Seal Your Home Against Insects and Rodents

Why exclusion beats extermination

Pest control chemicals treat the symptom. Exclusion — physically sealing the entry points — treats the cause. A mouse can squeeze through a hole the diameter of a pencil (1/4 inch). Carpenter ants enter through wood-to-soil contact. Wasps nest in soffit gaps. Cockroaches follow plumbing penetrations. By sealing these entry points, you prevent pests from entering in the first place, reducing or eliminating the need for chemical treatments. Exclusion is a one-time investment ($200–$800 for a typical home) versus recurring extermination costs ($300–$600 per year).

Where pests enter: the exterior audit

• Foundation-to-siding junction: The #1 entry point. Walk the entire perimeter looking for gaps where the siding meets the foundation wall. Seal with exterior caulk or copper mesh stuffed into larger gaps
• Utility penetrations: Where gas pipes, electrical conduit, cable lines, AC refrigerant lines, and dryer vents pass through the exterior wall, there's almost always a gap. Seal with expanding foam (for gaps under 1 inch) or steel wool plus caulk (for rodent deterrence)
• Door sweeps and thresholds: If daylight is visible under an exterior door, insects and rodents can enter. Install or replace door sweeps ($5–$20) and adjust the threshold
• Weep holes: Never seal weep holes (they're needed for drainage), but install stainless-steel mesh inserts ($1–$3 each) to block insects while maintaining airflow
• Soffit and fascia gaps: Inspect where the roof meets the walls. Rotted or warped fascia creates entry for wasps, bats, and squirrels. Replace damaged sections and install mesh behind open soffit vents
• Window and door frames: Check for cracked or missing caulk around every window and door frame on the exterior. Re-caulk as needed
• Chimney cap and flashing: An uncapped chimney is an open invitation for birds, raccoons, and squirrels. Install a chimney cap with mesh ($100–$300 installed)
• Garage door seal: The rubber gasket at the bottom of the garage door compresses and cracks over time. Replace it for $20–$40 in materials

Materials and tools you'll need

• Exterior silicone or polyurethane caulk ($5–$8 per tube, 2–4 tubes for average home)
• Expanding foam — use pest-block formula that resists gnawing ($6–$10 per can)
• Steel wool or copper mesh for stuffing gaps before foaming ($5–$10)
• Door sweeps ($5–$20 each)
• Stainless-steel weep hole screens ($10–$20 for a 10-pack)
• Caulk gun, utility knife, flashlight, ladder

Landscaping changes that reduce pests

• Keep mulch beds at least 12 inches from the foundation — mulch holds moisture that attracts termites and ants
• Trim shrubs and tree branches so they don't touch the house — these are pest highways onto the structure
• Store firewood at least 20 feet from the home and elevate it off the ground
• Eliminate standing water from saucers, birdbaths, and low spots — mosquitoes breed in as little as a bottle cap of water
• Clean gutters so they drain properly — clogged gutters create damp conditions that attract pests to the roofline

When to call a professional

A handyman can perform a comprehensive exterior seal-up for $200–$600 in half a day. For active infestations (termite tubes, visible nests, rodent droppings), call a licensed pest control company first to treat the current problem, then seal entry points afterward. If you notice structural damage from carpenter ants or termites (soft wood, sawdust piles, hollow-sounding studs), you may also need a carpenter for repairs before sealing.