How to Seal Garage Door Gaps to Stop Pests

Gaps under your garage door are basically an open invitation for mice, spiders, and snakes to move into your home. Even a quarter-inch space provides enough room for a determined rodent to squeeze through, turning your garage into a staging ground for a larger infestation. Sealing these gaps is the most effective line of defense you have, far superior to traps or chemical deterrents. Done well, a garage seal creates a tight barrier that remains flexible in freezing temperatures and stands up to the weight of your vehicle. You aren't just blocking critters; you are also stopping drafts and wind-driven rain from entering your workspace. Focus on achieving a flush fit against the concrete and you will eliminate the primary vector for unwanted guests.

  1. Clean the Concrete First. Sweep the floor area beneath the closed door to remove dirt, grease, and debris. Scrub the concrete with a degreaser if necessary, then let it dry completely to ensure the adhesive bond holds.
  2. Get Your Measurements Right. Measure the width of the garage door opening from side to side. Add two inches to this measurement to account for any shifting or precise cuts needed at the corners.
  3. Lay Down the Adhesive. Dry-fit the rubber threshold seal to ensure it rests correctly behind the closed garage door. Apply the included construction adhesive in a thick bead along the floor inside the lines you marked.
  4. Press and Let Cure. Press the rubber seal firmly into the bead of adhesive, ensuring there are no air pockets. Close the garage door gently onto the hump of the seal to create a perfect custom mold as it cures.
  5. Seal the Sides. Remove the old vinyl or rubber strips from the door jambs. Install new, thicker PVC or rubber side seals, nailing them into the jambs so the edge of the seal just touches the door when closed.
  6. Finish at the Top. Position the top seal against the header, ensuring the rubber flap makes full contact with the outside of the door. Attach it with screws or nails, checking that the door still operates smoothly without catching.