Rodent Proofing Checklist - 10 Places to Inspect Around Your Home

Inside: One to Five

1. Under the kitchen sink. Every pipe through the carcass and the wall behind. The most productive single point in most houses. 2. Behind the boiler. Where the pipework passes through the wall or floor, and the flue penetration.

3. The kickboard void. Kickboards unclip by hand; look for droppings, gnawed packaging and gaps at the pipe runs. 4. The airing cupboard and understairs cupboard. Both usually have an unsealed penetration into a floor or ceiling void. 5. The loft. Along the joists, at the hatch surround, around pipe and cable penetrations, and in the insulation.

Outside: Six to Ten

6. Air bricks. The whole perimeter, including behind bins and along the side return. Cracked, missing, rendered over, or below ground level. 7. The soil pipe and service entries. Where the soil pipe, gas, water, meter and telecoms cables pass through the wall.

8. Thresholds. Under the garage door, side and back doors, and any door with a worn or missing seal. 9. The extension junction. Where a later addition meets the original brickwork, at ground level and at the roof. 10. The roofline. Open eaves courses, lifted tiles, soffit joints, and any tree or fence reaching the roof.

What You Are Looking For at Each One

Gaps a biro fits into, for mice; anything thumb-width, for rats. Then the evidence that says a gap is in use rather than merely available: droppings, a greasy smear at a pinch point, fresh gnawing showing pale material, disturbed insulation, and nesting material.

Evidence matters more than the hole. A property has many openings and rodents use a few of them, so following the runs is what tells you which ones to spend the time on.

What to Seal Them With

Rodent-resistant metal mesh packed properly and finished with mortar or a fitted plate, done in a way that allows for pipe movement and heat. Purpose-made rodent-resistant air bricks or stainless grilles where ventilation has to be kept.

Not expanding foam, which they chew through in days and which hides the gap from later inspection. Not silicone alone. Not steel wool by itself, which rusts and works loose. If something was filled with any of those in the past, treat it as open.

The Timing

Do this in late summer, before the autumn influx, and do it when there is no activity inside. Proofing an occupied property traps rodents in the structure, where they cause more damage and eventually die somewhere you cannot reach.

Where there is current activity, treat first — £190 for a flat, £240 for a house, follow-up included — then proof at £180 for up to an hour, covering rats, mice and squirrels. An hour goes a long way when the survey has already established where to spend it.