Where Are Mice Getting In? Common Entry Points

If you have mice, the next question is always the same: how are they getting in? A mouse can pass through a gap far smaller than most people think, so the entry point is often something you would never notice.

This checklist follows a tour of the house, starting outside and finishing in the kitchen, where most mouse trouble ends up.

Around the outside walls

Begin by walking the perimeter. Look at the base of the walls for cracks in render, loose or missing mortar, and damaged air brick covers. Old properties with settled brickwork often have small gaps that are easy to miss.

Check where pipes and cables come through the wall. Gaps around these are very common, particularly after work by plumbers, satellite installers or electricians.

Climbing plants, stacked wood and clutter against walls give mice cover as they approach, so keeping a clear strip around the base of the building helps both inspection and prevention.

Doors and thresholds

Front, back and patio doors with worn seals or gaps under the bottom edge are easy routes. So are garage doors, which often have uneven floors and are a handy stepping stone into the house through an internal door.

Check that the door brush or threshold strip is intact. A gap you could slide a pencil under is worth fixing.

Garage doors are worth special attention because many are not designed to seal tightly, and mice that settle in a garage often move through to the house.

• Worn or missing door brush strips
• Gaps at the bottom of garage doors
• Cat flaps left open or damaged
• Loose door frames and damaged thresholds

Roof and loft

Mice are able climbers and can reach roof level via pipes, trellis and rough walls. Look at the eaves, soffits and fascias, as well as gaps beside roof vents and where a roof meets a wall.

In the loft, signs include droppings, disturbed insulation and nests. If you spot them, entry may be at roof height and not only through the ground floor.

Check the area around loft hatches and any places where the ceiling meets a chimney breast, as gaps here can lead into wall voids.

Inside: kitchens and utility rooms

Inside, the main weak spots are around the pipes under sinks, behind and beneath kitchen units, behind the washing machine and around boiler pipework. Gaps here allow mice to travel between floors and wall cavities.

Pull out a drawer or look behind the kickboard with a torch. Fine dark smear marks, droppings or gnawed edges will show where mice are moving.

In flats and terraced houses, mice can also travel between properties through shared walls and service ducts, so the entry point may not be in your own home.

Fixing gaps properly

Mice gnaw soft materials, so foam and thin plastic alone are usually not enough. Use hard-wearing materials designed to resist gnawing, and make sure repairs are tidy and complete.

Do not seal everything before checking whether mice are still inside, as they can be trapped in the structure. If you cannot find the way in, Essex Pest Solutions can inspect the property, pinpoint likely entry points and advise on proofing and treatment.

Recheck the repairs after a few weeks, and look again if new droppings or noises appear, since mice will test any weak patch.

Frequently asked questions