The Seam Between the Extension and the Old House
There is nothing careless about it; two structures built fifty years apart simply never meet perfectly. An outside wall becomes an internal one, with a knocked-through opening and a beam over it. Services are threaded through it. The new floor is laid to its own level. Every one of those details leaves somewhere dry, warm and permanently out of sight, which to a mouse is a good address.
The holes cut for services
Waste from the sink, the washing machine outlet, gas and water pipes, a boiler condensate run, the cable out to a light or a socket on the new wall: each one passes through masonry, and each hole is cut generously so the pipe can be pushed through. What fills the gap afterwards is often nothing at all, or a scrap of foam a mouse can open up in an evening. How mice get in takes these one at a time.
The step where two floors meet
The original rooms usually sit on suspended timber; the extension is normally a concrete slab, and the two rarely finish at the same height. The step between them, the packing beneath the newer floor and the line where old joists stop can leave a void that runs from under the old house into the base of the extension. It is the reason droppings appear in the extension while the nest sits somewhere else entirely.
Behind the units and under the appliances
A fitted kitchen supplies its own road network: the space behind the carcasses, the continuous run under the kickboards, the warm gap beside the fridge, the panel cut out at the back for a washing machine waste. Mice can live there for weeks and be heard nightly without ever crossing the floor in daylight. Mice behind kitchen units covers what can and cannot be done about that space.
Going up into a loft conversion
Where a loft has been converted, the pipes and cables serving it were generally taken up through the same corners of the house. Mice follow them and end up in the eaves cupboards and the leftover roof space behind the new walls, where they are heard through a bedroom wall rather than through a ceiling. Mice in a loft explains how they manage the climb.
Where to Look in an Extended House
- Droppings along the back of whichever cupboard sits nearest the knocked-through wall
- Black grains inside the kickboard run, visible as soon as one panel is lifted out
- Chewed packet corners in a low cupboard: rice, cereal, flour and dry pet food first
- Scratching behind the fridge or washing machine once the house has gone quiet
- Droppings or shredded nesting material in the eaves cupboards of a loft conversion
- A musky smell in a cupboard that is normally kept shut
If the droppings look noticeably larger and the noise overhead sounds heavier, rat control in Queensbury may be the booking instead. The signs of mice sets out what to compare.
Worth Doing Straight Away
- Move open packets into tins or thick plastic boxes; cardboard and thin plastic hold nothing back
- Take the kickboard off one section of kitchen and look, rather than guessing from the noise
- Wipe under the toaster and around the cooker, since crumbs behind an appliance keep a small population going
- Leave the holes alone for the moment: sealing them now can shut mice into a floor or a wall
- Keep poison out of the loft and the floor void, where anything that dies cannot be reached
Around a Mouse Visit
What to say when you book
Say whether it is a house or a flat, roughly when the extension was added if you know, whether the loft has been converted, and which rooms the signs are in. Flag any run of kitchen that cannot be opened without tools, and any eaves hatch that has been papered or boarded over.
Before and after
Empty the base units that need reaching, clear enough out of the eaves cupboards to see into them, and keep pets elsewhere while work is going on. Afterwards you will hear what was found and what to expect; timing depends on the house and on how established the mice are, as how long mouse treatment takes explains. Call again if droppings appear somewhere new or the noise shifts to another part of the house.
Closing the Seam for Good
The lasting fix is dull and specific: fill each service hole properly, close the gap under the kickboards, block the route beside the soil pipe where it passes a ceiling. Small accessible gaps of that sort are what rodent proofing in Queensbury is for, once treatment has finished. Mouse-proofing a property goes through what holds up over time, and why mice keep coming back describes what happens when a single hole gets left.
For mice in converted flats and timber-floored terraces elsewhere in the borough, see Mouse Control Brent. Neighbouring Preston has the same pattern of extended interwar houses.
