Damp Proofing Frequently Asked Questions

Typical signs include dampness concentrated at the base of a ground-floor wall, a visible tide mark, peeling paint or wallpaper, powdery salt deposits and crumbling plaster. These symptoms are not proof on their own: leaks, bridged DPCs and other defects can look similar. See our rising damp service.

Rising damp generally affects the lower part of ground-floor walls. Condensation often appears on cold surfaces, windows, corners, ceilings and behind furniture, and may be accompanied by surface mould. The pattern, location, weather and construction all matter, so the moisture source should be diagnosed before treatment.

Yes. Paving, soil, render or other materials above or across the damp proof course can allow moisture to bypass it. Lowering the external level, forming a suitable drainage detail or another targeted repair may be more appropriate than injecting a new DPC. Read about high ground levels and bridged DPCs.

Where suitable, we install a remedial chemical DPC by drilling a specified pattern into the mortar bed or masonry and introducing the selected damp-proofing material. The correct installation height, spacing and depth depend on the wall construction, internal floor and external ground levels. Learn more about new DPC installation.

Not always. Replastering may be recommended where the existing plaster is loose, degraded or contaminated with hygroscopic salts that continue to attract moisture. We assess the required extent wall by wall and show it clearly in the quotation.

Drying time varies with wall thickness, ventilation, heating, season and the treatment used. Breathable finishes are normally preferable during drying. Follow the project-specific guidance supplied after the work and avoid impermeable wallpaper or coatings until the wall is suitably dry.

Below-ground walls and other areas subject to water pressure may require a designed waterproofing system rather than a conventional DPC. The construction, intended use and water risk should be considered before selecting the system. See our waterproofing and tanking service.

Photos, measurements and a description can help us give initial guidance. A reliable quotation may still require an on-site inspection because wall thickness, construction, access and the source and extent of moisture vary from one property to another.

Yes. After assessment, we can provide a written quotation explaining the proposed work and price. The document states the acceptance period and the scope and terms that apply to that particular project.

Some noise, dust and local removal of skirting, radiators or plaster may be necessary, depending on the treatment and access. We explain the required preparation in advance and protect work areas and access routes as appropriate. Where practical, parts of a DPC installation may be completed externally.

In many cases, yes. This depends on the scale and location of the work, household circumstances and the materials being used. We will discuss access, ventilation, room use and any preparation with you before the start date.

Guarantees are available for qualifying work. The duration, treated areas, exclusions and any transfer terms are confirmed in the written quotation and guarantee documentation for your project. Please rely on those documents rather than a general website statement.

Yes. Visit our damp-proofing case studies for examples of completed projects across London and Surrey, including the problem found, treatment selected and repair process.

We work across South West London and Surrey, including Wimbledon, Wandsworth, Tooting, Putney, Kingston, Sutton, Epsom, Banstead, Reigate, Weybridge and surrounding locations. Visit the areas of work page for local information and coverage.