With temperatures dropping substantially for the first time this fall, you’re not the only one thinking about staying warm this winter. While you’re switching out your closets and digging out winter coats, hats, and gloves, the small rodents and critters — mice, rats, possums, raccoons, skunks, chipmunks, woodchucks, and more — in your neighborhood are seeking warm, safe places for cold weather shelter. Below, find our best tips for how to prevent that shelter from becoming your deck, shed, or basement.

Evict existing critters

It’s very important that before you take measures to seal off areas under your deck or in your shed or basement, you check to make sure there aren’t already some living there. The best way to do this is to remove the things making the area a warm and inviting home. Clear out any vegetation, dead brush and leaves, and debris. Rodents and other critters are looking for a dark area to nest in, so letting more light in may encourage them to leave on their own. Debris like sticks, cardboard boxes, leaves, brush and yard waste are perfect nesting materials too, so removing those may send them seeking a cozier shelter.

If you’re storing trash and recycling bins near the porch or deck, move those elsewhere as they’re an easy source for food and nest materials.

Consider setting traps. There is a downside to setting traps, however — make sure you’re able to check them regularly and easily reach them again, because any rodents trapped that start to decay may attract even more critters. If you have pet cats or dogs too, keeping them away from the traps may a difficult task.

Prevent animals from settling in in the first place

In this case, the best offense is a well-set defense. To prevent rodents and other critters from settling in under your deck, or in your shed or basement, in the first place, the best method is to inspect the areas and think like an animal in search of shelter. Look for any cracks or openings in your shed or house foundation — and think small! Mice can squeeze into an opening the size of a dime.

Then gather your tools and materials. For sealing cracks, you’ll want caulk and a caulk gun and for tiny holes, steel wool. Walk around the entire perimeter, sealing and stuffing all the holes and cracks you see. Have someone shine a flashlight in from the exterior to find any openings you’ve missed. Not only will this process prevent bugs and animals from creeping inside for the winter, it will also help prevent cold air from leaking in.

Next up is your deck. The tools you need for this job are a staple gun, wood-lattice, screws, drill, and sturdy, rodent-proof steel mesh. Dig a trench of a few inches into the ground around the base of your deck. This will prevent critters from digging their way under the mesh easily. Wrap and secure the mesh screen around the base of the deck using your staple gun, and then install the wood lattice over it, securing it at the top to be deck with your screws.

Think you may already have an infestation?

Signs of an infestation include droppings, urine trails, established nests, seeing dead or live rodents or animals, and finding holes chewed in food storage in the pantry.

If you think you already have an infestation, the best course of action is to call a pest control company. Once they’ve helped you eradicate the problem, you can follow the steps above to seal off your home, deck, and porch from another critter invasion.