How to Keep Rats Out of Your Car Engine, Garage, and Attic

Roof rats are exceptional climbers. They rarely enter a home at ground level. Instead, they use adjacent trees, fences, and power lines to drop onto your roof, eventually chewing through a weak gable vent to access the warmth of your attic.

• Trim the Canopy: Use a pole saw to trim back any tree branches hanging over your roof. A roof rat can easily jump 3 to 4 feet horizontally. Maintain a strict 4-foot “no-fly zone” between the tree canopy and your roofline.
• Cap the Vents: Standard aluminum attic louvers and gable vents are too flimsy to stop a rat. Cut a square of 1/4-inch galvanized hardware cloth (never use window screen or chicken wire) and staple it securely to the inside framing of every attic vent.

The bottom corners of a roll-up garage door are the most frequent entry points for field mice and Norway rats. The soft rubber weatherstripping offers zero resistance to a determined rodent.

First, replace the bottom U-shaped rubber seal if it is cracked or no longer sits flush against the concrete. Next, buy a roll of aluminum flashing. Cut small pieces of the flashing and fold them over the bottom exterior corners of the garage door frame (where the rubber meets the wood). Nail the metal flat. If a rat tries to chew the corner to widen the gap, it hits solid aluminum and breaks its teeth.

Any time a pipe or wire enters your garage or attic from the outside, the builder cut a hole larger than the pipe itself. Rodents follow the warmth emanating from these pipes directly into your home.

Check the AC coolant lines, water heater vents, and exterior electrical conduits. If the gap is larger than a pencil eraser, stuff it tightly with copper mesh (copper won’t rust and degrade like steel wool). Then, use a high-quality silicone caulk to seal the mesh in place, stopping the air drafts that attract the rodents.

If you have had rodents in the past, this is the most critical step that DIYers miss.

Before you seal any entry point, you must scrub the surrounding wood, brick, and concrete with an enzymatic odor neutralizer (the kind used to clean up dog urine). This breaks down the proteins in the rat’s urine, permanently erasing the trail and confusing future rodents.