How Mice Get Into Your Home and How to Keep Them Out

A mouse needs very little room

Mice have flexible bodies and can pass through a hole not much wider than a pencil. If a mouse can get its head through, the rest of it can usually follow. Because of this, a house that looks tightly built can still have several ways in. Mice also climb well, run along pipes and cables, and jump surprisingly high. An opening does not need to be at ground level for a mouse to use it, so it pays to think about the whole building and not just the base of the walls.

Common entry points

Most routes in are unplanned gaps left during building work or created by wear over time. Older houses have more settling and cracking, while newer estates often have small gaps where services pass through the wall. Check the outside of the property first, working slowly around the walls with a torch. Look for any gap where something passes through or meets another surface.

• Gaps around pipes and cables where they enter the house
• Damaged or missing air bricks and worn vent covers
• Gaps under or around badly fitting doors, especially garages
• Cracks in brickwork, render or where an extension joins the house
• Loose roof tiles, gaps at eaves and unsealed loft hatches

Why they choose your house

Mice come in for food, warmth and shelter. Gardens with long grass, compost heaps, stored firewood and piles of rubbish give them cover close to the walls. Seed spilled on the ground and outdoor pet food also attract them. In Essex, homes beside farmland, field edges, allotments and woodland tend to see mice moving in as the nights get cooler. Coastal and estuary areas are not immune either, as mice can live in sheds, outbuildings and beach huts before moving into houses.

Simple things you can do yourself

Tidy the outside first. Cut back vegetation touching the walls, move wood piles and compost away from the house and keep bins closed. Indoors, store food in tight containers and keep stored boxes off the floor so any activity is easier to spot. Small gaps around pipes can be closed with materials that mice cannot chew through easily. Fit brush strips to door bottoms and make sure air bricks have intact covers. Work carefully and never block an opening while you think a mouse may be inside.

What to avoid

Do not fill holes with foam or soft filler alone, as mice can gnaw straight through it. Avoid stuffing a gap if there are signs of live activity behind it, because trapped mice often chew a fresh way out somewhere else, sometimes into a room. Also avoid laying poison as a first response. It does nothing about the gaps, and it risks harming pets, children and wildlife, as well as leaving a dead mouse in a place you cannot reach.

When to call a professional

If you keep seeing signs after tidying up, or you cannot find where they are getting in, ask us to help. We look at the whole property, including roof spaces, voids and outbuildings, find the routes mice are using and deal with the activity safely. We can then advise which gaps to close and in what order. Proofing is most effective once the mice have been dealt with, so the work is done in the right sequence.

Keeping them out for good

Proofing is not a one-off job. Walk around the house a couple of times a year, ideally before autumn, and check that seals, vents and door brushes are still in good condition. Repair cracks as they appear, and keep the garden tidy near the walls. If you have had mice before, check for new signs regularly, such as droppings in cupboards or gnawing on packaging. Catching a problem when it is small is far easier than dealing with a settled colony.