Sealing Your Home Against Bugs: A Room-by-Room Exclusion Guide

Bugs don't appear in a house at random — they follow specific entry points and are drawn in by specific conditions, and both are fixable without a single pesticide. Exclusion, done room by room, does more long-term good than almost anything else you can do.

The exterior perimeter

Start outside, since this is where most entry points live. Check where utility lines, cables, and pipes pass through the exterior wall — these penetrations are rarely sealed as tightly as the wall around them, and a bead of silicone caulk closes the gap permanently. Check the bottom of exterior doors for a worn or missing door sweep; a quarter-inch gap under a door is a wide-open lane for crawling insects. Foundation cracks deserve the same caulk treatment, especially anywhere a crack is wide enough to see daylight through.

Basements and crawl spaces

Moisture is the single biggest driver of pest activity in a home, and basements and crawl spaces are where it usually starts. A running dehumidifier keeps humidity down where silverfish, sowbugs, and other moisture-loving bugs would otherwise thrive. Firewood stored against an exterior wall is worth moving at least 20 feet away and up off the ground — it's both a food source and a direct bridge for wood-dwelling pests, and stacking it against the house undoes a lot of the other sealing work.

The kitchen and pantry

Indoors, the kitchen is where food-seeking bugs concentrate. Store dry goods — flour, cereal, pet food — in airtight containers rather than their original cardboard or paper packaging; pantry moths and flour beetles can chew directly through a cardboard box but not through sealed plastic or glass. Wipe up crumbs and spills the same day rather than the same week, and don't leave pet food out overnight.

Attics and upper floors

Window and door screens with even a small tear are an open invitation to flying insects, and a patch kit fixes one in minutes. Attics are where overwintering bugs — cluster flies, ladybirds, boxelder bugs — end up gathering in fall, having entered through soffit vents or small gaps under the roofline; a quick check of vent screens before autumn is worth the ten minutes it takes.

Storage areas everywhere

Stacked cardboard boxes are both food and shelter for silverfish, roaches, and carpet beetles alike. Swapping cardboard for sealed plastic storage bins in basements, attics, garages, and closets removes both problems at once, and it's one of the highest-value five-minute changes available.

Bathrooms and garages

Bathrooms combine two conditions bugs like at once: consistent moisture from showers and sinks, and small gaps around pipe penetrations under the vanity. Silverfish in particular gravitate toward bathrooms for exactly this reason, grazing on the starches in wallpaper paste, bar soap, and shampoo residue. A bathroom fan run long enough after showering to actually clear the humidity, plus a caulked gap under the sink, addresses most of it. Garages are worth a separate pass too — the gap under an overhead door is typically far larger than any other entry point in the house, and a garage door weather seal closes it in under an hour.

It's worth revisiting these same rooms on a schedule rather than once and forgetting about it. A door sweep compresses over time and stops sealing as tightly as it did new, caulk can crack or shrink away from a gap after a few seasons of temperature swings, and a garage weather seal wears fastest of all given how often the door cycles open and closed. An annual walk-through with the same checklist you used the first time catches this kind of gradual failure before it reopens an entry point you'd already dealt with.

Turning this into a plan

Rather than trying to remember all of this, our Infestation Risk Checklist turns these same factors into a scored checklist — check off what applies to your home and get a weighted risk band plus the specific fixes worth prioritizing first, starting with whichever carry the most weight for your situation.