House mice can squeeze through a gap the width of a biro lid. That makes proofing fiddly, but absolutely worthwhile — most of the call-outs we get between October and February could have been avoided with a couple of hours' work in autumn.
Outside the property
- Walk the perimeter looking for gaps around air bricks, soil stacks, gas and electric meter boxes and weep holes.
- Check where pipes and cables enter the building — silicone alone isn't enough; pack with stainless wire wool first.
- Cut back ivy and shrubs touching the walls or roof — they give rodents a ladder up to the eaves.
- Make sure garage door bottom seals are intact; a worn rubber seal is one of the most common entry points.
Inside the property
- Look under the kitchen kickboards for gaps around waste pipes — a frequent unseen runway.
- Check the airing cupboard and behind the boiler for daylight or droppings.
- In the loft, inspect around soil pipes and downlighters; LED downlight cut-outs are a classic mouse motorway.
- Store dry food in sealed glass or hard plastic — never leave open bags in cupboards.
If you've already heard scratching
Proofing alone won't shift mice that are already inside — you'll just trap them in. We'd recommend a combined treatment-and-proofing visit so the existing population is removed before the entry points are sealed.