Seal Your Home: The Fall Pest Prevention Checklist

When the first cool night rolls through in early fall, every mouse, spider, and stink bug within a hundred feet of your foundation starts looking for a warm place to overwinter. Your house is that place. The good news is that pest pressure in fall is almost entirely a sealing problem, not a spraying problem. If a bug can't get in, it can't set up shop in your attic in November.

This is the same checklist our technicians run when a customer signs up for our fall exclusion service. You can do most of it yourself in a weekend with a caulk gun, a roll of copper mesh, and a good flashlight.

Start at the foundation

Walk the perimeter of your home slowly. You're looking for any gap wider than a pencil — that's all a house mouse needs. Common trouble spots are the gaps where utility lines enter (electrical, cable, gas, AC line sets), weep holes in brick veneer, cracked mortar, and settled concrete pulling away from siding. Stuff every hole with copper mesh or stainless steel wool first, then seal over it with a paintable exterior caulk or expanding foam rated for pests. Skip regular steel wool — it rusts within a season and mice will chew right through the flakes.

Doors and thresholds

Get down on the floor and look at the bottom corners of every exterior door in daylight. If you can see light, insects and mice are getting in. Replace worn door sweeps and add corner seals to the two spots where the sweep meets the weatherstripping — that little triangle is the single most common mouse entry point in a suburban home. Garage doors deserve their own sweep and side seals; a two-car garage door on a cold night pulls warm air out and pests in.

Windows, vents, and eaves

Check every window screen for holes and every window frame for cracked caulk. Move up to the roofline: gable vents, soffit vents, ridge vents, dryer vents, and bathroom exhaust vents all need intact hardware cloth backing (¼-inch mesh, not window screen — window screen is too flimsy and clogs with lint). Chimneys need a proper cap with a spark arrestor. Bats, squirrels, and raccoons all exploit torn vent screens, and a squirrel in the attic is a much bigger problem than a mouse in the pantry.

The garage and utility room

Garages are the transitional zone where outdoor pests become indoor pests. Pull everything off the floor and onto shelves — cardboard boxes on concrete are a rodent hotel. Store pet food, birdseed, and grass seed in metal cans with tight lids. Check the door between the garage and the house; it's technically an exterior door and needs the same sealing treatment. Look at where the water heater and furnace lines penetrate the wall and seal any gaps.

Landscape pressure

Trim shrubs so nothing touches the siding. Overhanging tree limbs give squirrels and rats a highway to your roof — anything within six feet of the house should come off. Move woodpiles at least twenty feet from the foundation and elevate them off the ground. If you have mulch beds against the house, keep the mulch layer under two inches; deeper mulch stays damp and breeds roaches, earwigs, and millipedes right against your siding.

When to call a pro

If you find rodent droppings, gnaw marks on wood or wiring, or grease trails along baseboards, sealing alone won't fix an active infestation — you need trapping and monitoring alongside exclusion. Same story if you're seeing dozens of stink bugs or lady beetles on sunny walls in October; by the time they're clustering, hundreds are already inside your walls and only an interior treatment will keep them out of your living space over winter.

Do the sealing work now, before the first frost. Every hour you spend with a caulk gun in September saves you a service call in January.