Basement tanking & waterproofing

Basements and cellars are more likely to suffer from damp due to surrounding ground moisture and hydrostatic pressure. Tanking is a proven method of waterproofing below-ground spaces by creating a protective barrier to resist water ingress.

We inspect the space, check the type of moisture ingress and recommend the most suitable approach - including preparation, waterproof coatings and compatible internal finishes.

When is basement tanking suitable?

Persistent damp on basement walls or floors
Flaking paint, salt deposits or crumbling plaster below ground level
Cellar conversion preparation and waterproofing
Water ingress through retaining walls

CALL 0800 955 3001

Our basement tanking process

Survey to identify moisture source and wall/floor condition
Preparation: removal of loose material, salts and failed coatings
Application of tanking slurry / waterproof coating system
Detailing around joints, corners and service penetrations
Advice on suitable replastering and breathable finishes

Case study 1: Damp cellar walls with salt contamination

A client had a cellar used for storage with persistent damp patches and white salt deposits.

We prepared the substrate and removed loose/contaminated materials.
We applied a waterproof tanking system to the walls.
We advised on compatible finishes and ventilation to support drying.

Result: The space became noticeably drier and more usable for storage.

Case study 2: Basement conversion preparation

A homeowner planned to convert a basement into a usable room and wanted a waterproof solution first.

We assessed the retaining walls and floor condition.
We installed a tanking system and detailed joints and corners carefully.
We provided guidance for follow-on works and finishes.

Result: A protected shell ready for conversion works.

FAQs - Basement tanking

Is tanking the same as a membrane system?

No. Tanking is a barrier coating applied to the structure, whereas membrane systems manage water behind a cavity membrane and direct it to drainage. We can advise which is best for your space.

Can you tank just one wall?

Sometimes, but it depends on how moisture is entering. In many cases a more comprehensive approach gives a better long-term result.

How long does basement tanking take?

Timescales vary depending on size, preparation and drying time. We'll confirm a clear schedule after inspection.

Where do you provide basement tanking services?

Basement and cellar waterproofing and tanking services are especially popular at homes in London, but also a regular service we carry out at properties in Sussex, Kent and Surrey. See our areas covered page for details.