5 Tiny Openings You Didn’t Know Let Fall Pests into Your Home—and How to Seal Them

We all know the fright and dread of spotting a spider in the shower or a mouse darting across the kitchen floor. The truth is, those creepy crawlers and furry intruders didn’t just appear out of nowhere; they were invited in through tiny, often-overlooked openings in and around your home.

As temperatures drop and outdoor conditions become less hospitable, pests start looking for warmth within our homes. The problem is that many homeowners never think to check these hidden entry points until it’s too late. But with a little attention and some quick DIY fixes, you can block pests before they make themselves at home. Here are five surprising places critters sneak inside, and how to seal them for good.

1. Utility Line Cutouts in Walls

Take a look behind your washing machine, under the kitchen sink, or in the basement. Where utility lines like gas pipes, dryer vents, or cable wires enter your home, builders often cut holes a little larger than necessary. Over time, those gaps widen, and suddenly you’ve created a tunnel that leads straight indoors.

How to Fix It: Use steel wool or mesh to tightly pack any gaps around pipes or lines, as rodents can’t chew through the material. Then, apply a layer of weatherproof sealant around pipes and cables to lock it in place. For larger cutouts, consider installing a rubber grommet or escutcheon (a flat decorative plate) for a clean finish.

2. Gaps Behind Siding and Trim

Your home’s exterior siding and decorative trim pieces might look tight, but pests know better. As houses settle and materials expand and contract with the weather, small separations can develop where siding meets windows, doors, or corners.

How to Fix It: Inspect siding seams and trim joints with a flashlight. If you see daylight peeking through, apply a bead of high-quality exterior caulk. For larger separations, a flexible foam strip can be inserted before caulking to create a tighter seal.

3. Dryer Vent Flaps That Don’t Fully Close

Dryer vents are designed with a flap that should close when the appliance isn’t in use. But dirt, lint, or weather damage often keeps the flap stuck open just a sliver. Small rodents, in particular, are notorious for slipping past these vents when they don’t seal properly.

How to Fix It: Check your dryer vent cover from the outside of your home. If the flap doesn’t sit flush when closed, clean away lint and debris. If it’s warped or damaged, replace the entire vent cover; it’s an inexpensive fix you can find at any hardware store.

4. Attic Vents and Roofline Gaps

Out of sight often means out of mind, and attic entry points are among the most overlooked. Tiny gaps where the roofline meets the house, or vents with worn-out screens, provide perfect openings for pests. Once inside, they can be tough to expel.

How to Fix It: Use binoculars to scan your roofline from the ground or climb safely onto a ladder for a closer look. Replace any torn vent screens with new hardware cloth or fine-mesh screening. For gaps along soffits (the underside of a roof's overhang), exterior caulk or spray foam designed for outdoor use works well.

5. Basement Window Wells and Cracked Frames

Basement windows and their surrounding wells are prime sneaking spots for pests. Over the years, wooden frames can rot, caulk can peel, or window wells can collect leaves and moisture, creating a perfect staging area for insects.

How to Fix It: Clean out window wells regularly and ensure they’re covered with fitted well covers to keep pests (and debris) out. For damaged frames, scrape away old caulk and reseal with fresh exterior-grade caulk.