Rodent guarantees are tied to proofing because baiting and proofing do different jobs. Baiting kills the rodents present. Proofing removes the route they used, and only the second job lasts. Rodent proofing in London is the usual condition on a rodent guarantee, because no firm can promise an outcome it has not physically controlled.
Rodent proofing is a condition of most rodent guarantees because a guarantee promises the absence of rodents, and only proofing can deliver that. A guarantee against re-infestation on an unproofed property would be a promise about the neighbour's drains, the freeholder's air bricks and the broken gully under the pavement outside — none of which a pest controller can see, own or repair.
A treatment guarantee is a voluntary contractual promise added on top of a customer's ordinary legal rights, and firms write only promises they can keep. Where proofing was declined, deferred or blocked by a freeholder, the risk is open-ended, and the guarantee is normally withdrawn or written to exclude re-entry.
Rodent proofing is physical building work, not a chemical treatment. It is the sealing, replacing and reinforcing of the gaps a rodent can use, in materials rodents cannot gnaw through. On a London house or flat it covers six things:
Drain repair is the part most often left out of a rodent proofing quote. Ask any firm quoting for rodent work whether drainage sits inside the quote or outside it, because a drain defect left unrepaired makes above-ground proofing decorative. Getting someone out to survey the property is the quick half of the job: 247 Pest Control states that same-day attendance is available across London and responds to emergency enquiries 24/7, while noting that attendance time cannot be identical for every call. That inspection is what turns an urgent call into a plan: the species named, the treatment chosen, and the earliest date it can happen. The proofing that follows is scheduled building work, quoted after the entry points have been found. A rodent job therefore has two turnarounds rather than one: the treatment half moves at the speed of a diary, while the proofing half waits on a drain survey, a materials order and a freeholder's consent.
A house mouse gets through a gap far smaller than most people check for, and the working trade rule is that if a pencil fits into a gap, a mouse fits too. Rats need more — roughly a two-finger gap — but a rat does not have to find one.
Gnawing is the mechanism that makes small gaps irrelevant. Rodent incisors grow continuously and are worn down by gnawing, so a rat or mouse enlarges a promising gap instead of abandoning it — through mortar, plastic waste pipe, foam, timber and plasterboard. A hairline gap at a pipe collar becomes a mouse hole, and a mouse hole in soft material becomes a rat run.
London properties make proofing harder because so much of the housing stock is shared. Victorian and Edwardian terraces, and the flat conversions carved out of them, share party walls, subfloor voids, roof spaces, pipe boxings and cable runs. A mouse population can move between flats without going outside, so the entry point that matters may be two floors below the flat with the droppings in it.
Rodent proofing in London therefore often fails when it is done to one flat in a converted house. Sealing the internal gaps of a single flat stops mice coming out of the void into that kitchen; it does not stop them living in the void. Work that holds on a converted or terraced building is building-wide — external envelope, subfloor, service risers and bin store — and that needs the freeholder's or managing agent's consent before anyone can quote for it.
A landlord must keep the structure and exterior of a rented home in repair, and that duty is where most proofing work sits. Gaps at pipe entries, broken air bricks, defective drains and failed mortar are defects of structure and exterior, so repairing them falls to the landlord, not the tenant.
Domestic hygiene, pests and refuse is one of the hazards rated under the Housing Health and Safety Rating System (HHSRS), the framework councils use to assess housing conditions and require works. An occupier must notify the local authority of a substantial infestation of rats or mice, and the authority must in turn keep its district free of rats and mice so far as that is practicable. Report the infestation and the disrepair together: a report about mice alone invites a bait box, while one naming a broken drain and two missing air bricks invites a repair.
The Campaign for Responsible Rodenticide Use UK (CRRU) Code of Best Practice pushes the trade towards proofing because it restricts permanent baiting and requires bait to be secured, recorded and monitored rather than left down indefinitely. Rodenticide left in place as a standing precaution causes secondary poisoning when owls, foxes and pets eat rodents carrying residues. Permanent baiting under the CRRU Code is justified only in defined high-risk situations, and must be documented.
Professional rodenticides are controlled products. They may be used only by trained, certificated operators, strictly to the product label and the stewardship conditions attached to it. Bait boxes go down for a monitored period, then come away, so what remains after the last visit is whatever proofing was done.
Six entry points account for most rodent access into London homes, and each has its own fix and its own responsible party.
| Entry point | How rodents use it | The proofing fix | Who is usually responsible |
|---|---|---|---|
| Gap at a waste pipe or cable entry | Mice travel wall and floor voids, emerging at the collar gap | Wire wool bedded in mortar, or a metal collar plate | Landlord when rented, as part of the structure; freeholder in common parts |
| Defective or missing air brick | Rats and mice enter the subfloor void and move up through floorboard gaps | Purpose-made rodent-proof vent that keeps airflow | Landlord or freeholder, as external structure |
| Gap under an external or communal door | Mice enter at night from bin areas, gardens and shared hallways | Bristle strip or door sweep, plus a metal kick plate where gnawing has started | Owner for a flat entrance door; managing agent for communal doors |
| Broken or redundant drain connection | Rats climb from the sewer through cracked pipework and missing rodding-eye caps | Drain survey, repair, capping, non-return valve | Owner for private drainage; the water company for the public sewer |
| Roof line, eaves and soffit gaps | Rats and squirrels reach lofts along the roof line, often from a neighbouring roof | Mesh to eaves and soffits, repair of loose tiles and fascia timber | Freeholder or building owner, as roof structure |
| Bin store or shared refuse area | Food waste feeds a population beside the building | Lidded intact bins, hard standing, a proofed store, refuse cleared on schedule | Managing agent, or the council for street refuse |
Proofing is usually quoted separately from treatment, because materials and labour depend on how many entry points exist and how reachable they are. On the treatment half of the job, 247 Pest Control publishes rat control and mice control from £214 for straightforward domestic treatments, naming pest type, property size, infestation level, visits needed, treatment method, access and urgency as the variables that move a figure. A published starting price is a floor for an easy job, not an estimate for a proofing programme.
Your landlord is responsible for the structural and external gaps. A landlord must keep the structure and exterior in repair, and that captures broken air bricks, failed mortar, defective drains and ill-fitting doors. Domestic hygiene, pests and refuse is also a rated hazard under the Housing Health and Safety Rating System, which the council can act on.
Expanding foam alone will not hold, because mice and rats gnaw through it. Foam is a filler, not a barrier. Pack the gap with wire wool bedded in mortar, or cover it with sheet metal or heavy galvanised mesh, then make good around it. Foam is acceptable only as backing behind a gnaw-resistant material.
Bait is placed for a monitored period, not left down indefinitely. The Campaign for Responsible Rodenticide Use UK (CRRU) Code of Best Practice restricts permanent baiting and requires bait to be secured, recorded and monitored, because rodenticide left in place risks poisoning owls, foxes and pets. Professional products must also be used strictly to their label.
Internal proofing of one flat can be done alone, but it rarely resolves a shared infestation. In a converted terrace, mice live in party walls, subfloor voids and service risers, and move between flats without going outside. Closing the external envelope, subfloor and bin store needs the freeholder's or managing agent's consent, which is why whole-building work takes longer to arrange.
