First, Is It a Return or the Tail End?
Activity during and after a treatment tails off rather than stopping at once. A few fresh droppings in the week or two after treatment may be the last of the original mice rather than new ones. The questions to ask are where and how many: droppings thinning out in the same places is the end of a problem; droppings appearing somewhere new, months later, is a return.
How long the treatment itself should take is covered on the timeline page. This page is about the second case.
An Entry Point Was Missed
This is a very common reason. The obvious gap round the kitchen waste pipe was sealed, but there was a second route behind the boiler flue, or under the back step, or where a cable was added years ago. Mice found the one that was left.
The clue is where the droppings reappear. If they come back in the same corner as before, the route that fed that corner is still open. If they turn up somewhere new, look at what is on the other side of that wall.
Next Door Has Them
In terraced and semi-detached houses and in flats, the voids under floors, in lofts and behind boxed-in pipes often run between homes. You can treat and proof your own property properly and still see mice again if the house next door is feeding a population of its own.
The signs are activity mainly along the party wall, or in a loft that is only divided from the neighbour's by a partial wall. A conversation with the neighbour is worth having; it is much easier to solve on both sides at once. If you rent, the landlord advice page covers who usually deals with what.
Something Is Still Feeding Them
If food is still easy to get, a building stays worth coming back to. Look again at the things that are easy to forget:
- A sack of dog food or bird seed in the garage or shed.
- Pet bowls that have gone back to being left down overnight.
- A compost heap taking cooked food close to the house.
- Bin bags stored beside the bin rather than in it.
- The strip behind the cooker, which nobody has looked at since the treatment.
New Gaps, Garages and the Season
- Building work. A new boiler, extension, kitchen, broadband line or outside tap all mean new holes through the wall. Mice returning shortly after work was done nearly always points to one of them.
- Garages and outbuildings. These are rarely proofed to the same standard as the house. Mice can live in a garage all year and move into the house through the connecting door or a shared wall when conditions change.
- Seasonal pressure. Mice press harder on a building when it turns cold. A gap that was never used in summer can suddenly be found in autumn. A return in October or November is often this: not a failed proofing job, but a weakness that was never tested before.
Look at where they came back, not just that they did. The room and the wall where droppings reappear point to the cause far more often than anything else.
What to Do About It
Note where the new droppings or noise are, and when they started. Think about anything that has changed: building work, a new neighbour, a new pet, stored food moved into the garage. That will usually narrow it to one of the causes above.
Once the return is dealt with, keeping them out for good is a matter of routine checks, and the prevention routine sets that out. If you need them treated again, it is a fixed £260, confirmed before anything is booked. Ring 0118 336 1366.