Service

Basement & Cellar Tanking

Type A cementitious tanking seals your basement or cellar walls and floor against water and ground moisture — a proven barrier system, expertly applied across London.

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A watertight barrier for below-ground walls

Tanking is one of the oldest and most reliable ways to waterproof a basement or cellar. A cementitious waterproof coating is bonded directly to the masonry, creating a continuous barrier that stops water and damp passing through into the room.

Done properly, tanking transforms a cold, damp cellar into a dry, usable space suitable for storage, utility or — with the right build-up — habitable rooms. The key is meticulous preparation and correct detailing at every junction, which is where specialist experience matters.

We tank cellars and basements across London's period property stock, matching the system to the condition of the structure and how you intend to use the space.

Tanking is ideal when

You have a damp cellar you want to use for storage or utility
Walls show moisture, salting or blown plaster below ground
You're creating a dry, sealed space against solid masonry
An older tanking system has broken down and needs renewing
You need a robust barrier as part of a combined waterproofing design

How Tanking Works

Careful preparation and correct detailing are what make a tanking system last.

Survey & preparation

We survey the space, then hack off old plaster and defective render back to sound masonry to give the tanking a clean substrate.

Apply the tanking system

Multiple coats of cementitious waterproof slurry are applied to walls and floor, forming a continuous, seamless barrier.

Fillet, detail & re-plaster

Wall-to-floor junctions are sealed with a waterproof fillet, and the surface is rendered ready for finishing.

Guarantee

The completed system is checked and you receive written guarantees on materials and workmanship.

Type A System

Barrier tanking to BS 8102.

Free Survey

Written report and fixed quote.

Guaranteed

Materials and workmanship warranty.

Tanking FAQs

What is tanking? +

Tanking is a Type A 'barrier' waterproofing system. We apply a cementitious slurry or coating to the walls and floor of a basement or cellar, forming a continuous seal that physically blocks water and moisture from entering the internal space.

How much does basement or cellar tanking cost in London? +

Cost depends on the area to be treated, wall condition and preparation required. We provide a fixed written quotation after a free survey — most jobs are priced per square metre of treated surface.

How long does tanking take to install? +

A typical cellar or basement can be prepared and tanked within a few days to a couple of weeks, depending on size and how much preparation and re-plastering is required. We confirm the timeline in your quotation.

Is tanking or a cavity drainage membrane better? +

Both are valid to BS 8102. Tanking (Type A) resists water with a barrier; a cavity drainage membrane (Type C) manages water to a sump. For habitable London basements we often recommend Type C or a combined approach, but tanking is well suited to many cellars and lower-risk conditions. Our survey determines the best fit.

Basement & Cellar Tanking Across London

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Get a Tanking Quote

Book a free survey and we'll assess your cellar and provide a fixed written quotation.

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