Most rats live in nests or burrows. Burrows are holes in dirt, wood or concrete that range from 1-inch to 4-inches wide. Burrows can be found under bushes and plants, but are also commonly found in the floorboards and walls of homes. Filling in these burrow holes can help prevent rats from establishing nests and access points into your home, and from causing damage to insulation and interior walls.
Locate the rat burrow. A typical hole is approximately 2 inches in diameter. Look for holes in floorboards and at locations where wood may have rotted. Pay close attention to cluttered areas, and the areas around water or gas pipes.
Seal any burrow holes with a wire mesh made from copper, aluminium or stainless steel. The holes in the mesh should be no more than 1/4-inch wide. For holes smaller than 1 inch, a metal pot scrubber can be used.
Seal the holes with a cement-based wall plaster after stuffing.
Block the space between the door and the floor by attaching a metal kick plate to the door. Rats often use this open space for passage instead of a burrow hole.
Make sure that you are not sealing any rats into a space when stuffing the burrow hole. Sprinkle flour near the hole to confirm when the animals have left the space.