Pest-Proof Your Garage This Weekend for Under $150

My garage was a disaster. Mice in the wall insulation, spiders in every corner, and crickets that scattered when I flipped the light on. Spent a full Saturday fixing it and about $130 at the hardware store. That was three years ago. Haven't had a single mouse since.

This isn't a complicated project. Most of the work is identifying gaps and sealing them. Here's everything I did and what it cost.

The Garage Door: Your Biggest Weak Point

Walk into your garage, close the door, and turn off the lights. If you see daylight at the bottom, mice can get in. A mouse needs a gap about the width of a pencil. Rats need about a half inch. That strip of light under the door is an open invitation.

A garage door threshold seal fixes this. It's a rubber strip that adheres to the concrete floor where the door meets it, creating a tight seal when the door closes. I used a Tsunami Seal threshold kit from Home Depot. Cost me $35 for a 16-foot double door. Installation took 20 minutes: clean the concrete with a wire brush, peel the adhesive backing, press it down, done. No drilling, no special tools.

Side gaps along the garage door tracks are the other problem spot. The rubber weatherstripping on the sides of the door compresses over time and leaves channels that bugs and mice travel through. Replacement garage door side seal runs about $15 per side. Pull the old one out of its track, slide the new one in. Ten minutes per side.

The Wall Between Garage and House

This is the wall that matters most because it's the path from garage to living space. Every pipe, wire, cable, and duct that passes through it is a potential pest highway. The gap around a water heater flue or a dryer vent duct is often big enough for a mouse.

I went around with a flashlight and marked every penetration with blue tape, then sealed them one by one. Small gaps around wires and pipes: stuff in a pinch of steel wool and cover with silicone caulk. Mice won't chew through steel wool. Caulk alone they'll eat through in a week. The combo works. A bag of steel wool is $4, a tube of silicone caulk is $6.

Larger gaps around duct work or where multiple pipes come through: fire-rated expanding foam. Great Stuff Fireblock is $7 a can and it's orange so you can see where you sprayed. Don't go nuts with the foam. A little expands a lot. Cut the excess with a utility knife once it cures.

The door from the garage into the house needs a sweep on the bottom. If it doesn't have one, a $10 aluminum and rubber door sweep from the hardware store screws on in five minutes.

Fix Your Storage Game

Everything on the floor is pest habitat. Cardboard boxes, stacked newspapers, that pile of rags in the corner. Mice nest in soft materials. Roaches eat cardboard glue. Spiders hide in clutter because their prey hides in clutter.

Three changes made the biggest difference for me:

Wire shelving units. I bought two 5-shelf chrome wire racks, $50 each at Costco. Everything goes on shelves, nothing on the floor. Wire shelving is better than solid shelving because there's nowhere for pests to hide on the shelf surface and you can see what's behind things.

Plastic bins instead of cardboard. Replaced every cardboard box with a snap-lid plastic storage bin. A 30-gallon tote runs $8-12. Mice can't chew through hard plastic (they can chew through soft plastic storage bags, so don't use those). Label the bins so you're not opening and closing them constantly.

No pet food or birdseed in the garage.I learned this one the hard way. A 25-pound bag of dog food in the garage is a neon sign for every mouse and rat within smelling distance. Even in a sealed bin, the scent escapes. Store pet food and birdseed inside the house in a metal trash can with a tight lid if you must keep large quantities.

Lighting: A Quick Win for Spiders

Bugs swarm standard white LED and fluorescent garage lights at night. Spiders build webs near those lights because that's where dinner congregates. Switch your exterior garage lights and any fixture near the garage door to yellow or amber LED bulbs. They produce wavelengths that attract far fewer flying insects.

A two-pack of yellow LED bug light bulbs costs $6-8 at any hardware store. Screw them in, done. I replaced the bulb over my walk-in garage door and the spider population around that door dropped noticeably within a couple weeks. Fewer bugs at the light means fewer spiders building webs to catch them.

Common Garage Pests and What to Do About Them

Mice. The sealing work handles 90% of the problem. For any mice already inside, snap traps along the walls where you've seen droppings. Peanut butter bait. Check traps daily. Four to six traps in a two-car garage is about right. A pack of six Victor snap traps costs $5. For bigger rodent issues, our rodent control guide goes deeper.

Spiders. Knock down webs with a broom. Switch to yellow lights. Reduce clutter so they have fewer places to hide. A garage with wire shelving, plastic bins, and amber lights has very little spider habitat left. Most garage spiders are harmless, but black widows do hang out in garages -- check dark corners and behind stored items before reaching in blind.

Crickets. They enter through the same gaps as everything else. Once the door seals and wall penetrations are handled, crickets drop off. Sticky traps along the walls catch stragglers. A pack of 12 glue boards runs $8.

Wasps. Paper wasps build nests in the ceiling corners and along the garage door tracks. In spring, knock down small nests early before the colony grows. A can of wasp spray ($5) handles individual nests. If you've got a large established nest or ground-nesting yellowjackets under the garage slab, call a professional. Getting stung twenty times isn't worth the $4 you saved.

Total Cost Breakdown

Here's roughly what my Saturday project ran. Your numbers will vary based on garage size and what you already have:

Garage door threshold seal: $35. Side weatherstripping (both sides): $30. Steel wool and silicone caulk: $10. Fire-rated expanding foam (2 cans): $14. Interior door sweep: $10. Snap traps (6 pack): $5. Yellow LED bulbs (2 pack): $7. Glue boards (12 pack): $8. Total: around $120 in materials.

Shelving and plastic bins are extra if you don't already have them, but those are one-time purchases that serve a purpose beyond pest control. The sealing work itself is the critical part, and that's the cheapest line items on the list.

For a room-by-room approach to the rest of your house, check our full pest-proofing guide. The garage is step one, but kitchens, bathrooms, and attics all have their own weak spots.