Pest Exclusion 101: How to Seal Your Home from Bugs & Rodents

Walk the entire exterior perimeter of your house. You are looking for two specific sizes of gaps:

• The Pencil Test: A house mouse can collapse its skeleton to fit through any hole or crack the diameter of a standard #2 pencil (about 1/4 inch).
• The Dime Test: A juvenile rat can squeeze through a hole the size of a dime (about 1/2 inch).

Pay special attention to where the siding meets the foundation, where air conditioning lines enter the wall, and around exterior dryer vents. Mark every gap you find.

When you find a hole larger than 1/4 inch, you must use the professional standard technique to permanently seal it.

1. Take a strip of Copper Mesh (preferable to steel wool because it does not rust when exposed to California rain).
2. Use a screwdriver or putty knife to tightly pack the copper mesh deep into the void.
3. Take your caulking gun and pump exterior-grade silicone caulk over the copper mesh, smoothing it flush with the wall.

The caulk stops ants, roaches, and air drafts. If a rat tries to chew through the caulk, it hits the copper mesh, which cuts its gums and forces it to stop.

In California, the garage is the number one entry point for spiders and cockroaches. Look at the bottom corners of your garage door while it is closed. If you can see sunlight shining through, the rubber seal has failed.

Remove the old, flattened rubber gasket from the track on the bottom of the door. Slide a new, high-quality U-shaped rubber seal into the track. When the door closes, it should compress tightly against the concrete across the entire width of the garage. Ensure the side weatherstripping flaps are firmly pressing against the outside of the door.

Your living space must be isolated from the outside elements.

• Exterior Doors: Install heavy-duty bristle door sweeps on all exterior doors. The bristles should drag slightly on the threshold. Do not forget the door that leads from your house into your garage—treat it like an exterior door.
• Window Screens: A single tear in a window screen is a highway for mosquitoes and flies. Purchase a simple patch kit to repair small holes, or use a spline roller to replace the entire mesh on heavily damaged frames.
• Weep Holes: If you have a brick facade, do not caulk the vertical slits near the foundation (weep holes). They are necessary to let moisture escape. Instead, push specialized stainless steel weep hole covers into the gaps to stop bugs while allowing airflow.