Damp proofing in Kensington and Chelsea: an independent survey first

Why the survey comes before damp proofing in Kensington and Chelsea

In Kensington and Chelsea the question is rarely whether a damp proof course has failed. It is who is responsible for the fault that is wetting the wall, and what will actually stop it. That might be a freeholder, a neighbour or a managing agent rather than you. An independent report answers both, and we carry out no remedial work, so the answer is not shaped by a sale.

The quotes we are most often asked to review here are re tanking a basement that has a working drained membrane with a failed pump or silted channel, and injecting the ground floor walls of a stucco terrace that are wet from cracked render, a blocked front area drain or a leaking pavement vault. Neither addresses the cause, and both can run to very large sums in this borough.

If you are a landlord in Kensington and Chelsea, remember that the hazard is the damp and mould, not the absence of a damp proof course. Removing the cause is what deals with it, and that is often ventilation, heating, rainwater or a leak. If you are buying, a report before exchange tells you whether a damp proofing recommendation in the homebuyer survey is justified, and what the honest scope of work is.

Damp proofing methods, briefly

A chemical damp proof course, a physical course, a waterproof render, a drained membrane, a breathable plaster: each is sold as damp proofing, and each answers a different question. The survey's job is to establish which question the Kensington and Chelsea wall is actually asking.

In converted buildings the answer is often outside the flat altogether: a communal gutter, a front area drain, a parapet or a neighbour's raised garden. A damp proofing system inside the flat cannot fix any of those.

Kensington and Chelsea walls, and what they actually need

The borough's terraces are solid London stock brick behind stucco, built in lime. They stay dry when the stucco is sound and breathable, the parapets and valleys are clear, and the front area and vaults drain. Modern basements are engineered structures with membranes, drainage channels and pumps that need servicing. Neither needs an injected damp proof course as a rule.

• Servicing a basement drainage system: clearing channels, testing pumps, float switches and battery backups
• Repairing cracked stucco and repainting in a breathable finish, usually as a freeholder or communal matter
• Clearing and repairing front area drains and pavement vaults
• Repairing parapet and valley gutters above mansion flats and conversions

Basements: what usually fails

Most basements dug in this borough in recent decades use cavity drainage: a studded membrane on the walls and floor, a perimeter channel and a sump with pumps. The membrane rarely fails. What fails is the maintenance: silted channels, a pump that has not been serviced, a float switch that sticks, or a later alteration that pierced the membrane for a socket or a pipe.

An independent survey identifies which of those it is before anyone proposes stripping out and re tanking, and the report says which parts may still be covered by the original installer's guarantee.

What proper damp proofing involves in a London building

• A diagnosis in writing, with readings, before any specification
• External and communal faults identified and assigned: parapets, gutters, lightwells, shared drains
• A new damp proof course only on a Kensington and Chelsea wall that genuinely lacks a working one at low level
• Breathable or salt resistant replastering chosen for the wall, not a default system
• Consent considered where the building is listed or in a conservation area
• A record of what was done and why, which a future buyer's surveyor will ask for

Avoiding an unnecessary damp proofing bill

• Treat a free survey as a sales visit and do not sign on the day
• Ask how condensation, rainwater and ground level were excluded
• Ask whether any of the cause sits in the common parts and who should pay
• Be cautious of tanking an above ground wall in a Kensington and Chelsea conversion
• Ask for the readings, their locations and the height of plaster removal in writing
• If a purchase depends on it, get the report before exchange, not after

When a damp proof course is the right answer

We are not opposed to damp proofing, only to it being sold as the answer before the question has been asked. Where the readings, the pattern and the building all point to a missing or failed course in a Kensington and Chelsea property, the report recommends one and says how it should be done.

The survey fee is published and fixed before the visit. In Kensington and Chelsea, where replastering and making good in a period flat is expensive and disruptive, establishing whether the work is needed before it starts is the economical step.

After the survey you hold an independent record. Use it to obtain comparable quotes in Kensington and Chelsea, to negotiate a purchase, or to require a landlord or freeholder to act. We do no remedial work and recommend no contractor.

For the full picture of what a survey here involves, see damp surveys in Kensington and Chelsea.

Around Kensington and Chelsea

Chelsea and South Kensington

Stucco terraces and garden squares, many with deep modern basements. Basement system failures and stucco are the main subjects.

Notting Hill and North Kensington

Large Victorian houses converted into flats, and post war estates further north. Responsibility between flats and freeholders is the recurring question.

Damp proofing questions in Kensington and Chelsea

Book a survey before you pay for damp proofing

An independent survey before any damp proofing in Kensington and Chelsea. We do no remedial work. Written report within 24 hours.

Request a Survey or call 020 3355 4944