Mice in Finished Basements: A Guide for Overland Park Homes

Plenty of Overland Park homes have a finished basement. In north OP it's often the lower level of a split-level, with a family room and the laundry. In south OP it's a full walkout or daylight basement with a media room and a guest bedroom. Either way, mice love them. The finished walls that make the space comfortable also give mice a hidden hallway.

In most cases they're coming in at the rim joist, around pipes and vents or through a window well, and living in the unfinished parts: the utility room, under the stairs, the storage room. You usually don't need to open walls. Trap in the unfinished areas, seal the outside gaps and clean droppings wet, never dry.

Why the Lower Level Draws Mice

Basements sit at ground level, right where mice travel. The furnace and water heater keep them warm. Storage rooms are full of boxes, holiday decorations and old clothes, which make great nesting. And nobody spends much time down there, so mice go unnoticed longer. The garage next door is often how they got in, which is covered on the garage page.

In split-levels the lower level is only partly below grade, so the windows, dryer vent and utility lines are right at the soil line. Walkouts on sloped lots put a whole wall of doors and windows at ground level. Those are common in south Overland Park and on the hilly lots in west Shawnee. Split-levels in north OP and the older blocks around downtown often have paneling over block walls with gaps at the sill plate hiding behind it.

The Rim Joist and Other Ways In

The rim joist, where the wood floor framing sits on top of the foundation, is the big one. Mice also come through gaps around pipes and wires, window well drains and sump lines. These are the same spots that get checked during rodent exclusion:

• Gaps at the rim joist and sill plate
• Holes around gas, water and AC lines
• Dryer vents with a broken or missing flap
• Window wells packed with leaves
• The gap around the sump pump discharge pipe
• Unfinished utility rooms that open into finished wall cavities

Look Behind the Washer and Under the Stairs

You probably won't see mice out in the open. Start in the utility room, along the edges of the floor and behind the water heater. Look behind the washer and dryer. Open the storage boxes sitting on the floor. Check under the basement stairs and in the back of the closets. A musty smell in one room is a clue.

Listen at night, too. Light scratching or a quick scurry in a wall or the drop ceiling is what most people report. If the droppings are closer to a raisin than a grain of rice, it may be rats, and that calls for a different approach.

Keeping the Drywall in One Piece

Nobody wants to cut into new drywall, and the tech rarely has to. Traps go in the unfinished areas where mice travel, like the utility room, the storage room and under the stairs. Any bait goes in locked, tamper-resistant stations away from kids and pets. Mouse control has more on how a typical visit goes. The bigger job is outside. Sealing the rim joist, vents and pipes stops new mice from coming in, so the ones inside get caught and nothing replaces them. Tell us what kind of basement you have when you call. It helps the tech know where to look first.

Cleaning Up Without Stirring Up Dust

Open a window or run a fan. Put on gloves. Spray the droppings and nest material with disinfectant until soaked and let it sit a few minutes. Wipe up with paper towels, bag everything and take it out to the trash. Don't sweep or vacuum dry droppings. Run any bedding, toys or clothes the mice got into through a hot wash. If droppings are spread through a storage room, an attic or a crawl space, it may be worth having someone handle droppings and insulation cleanup.

See also: Mouse Control, Rodent Exclusion and Sealing, Attic and Crawl Space Cleanup