JB Damp Proofing - over 30 years experience in the damp proofing industry

Basement Waterproofing

Whether you are completely refurbishing your basement to utilise the space in your home, or a commercial client planning redevelopment - we offer tailor made waterproofing solutions.

Using leading brand products, we offer two types of waterproofing systems for earth retained wall, basements and vaults:


We provide a 10 year guarantee with this installation.

Cementitious replastering or tanking is a technique of applying an mixed slurry waterproofing application directly onto prepared walls and incorporating a floor lap. This application then forms a bond with the masonry causing any water ingress to divert away from the area. A floor lap must be incorporated to form a “tank” system, although with most basement/earth retained areas there are usually windows and doors. This system is not exactly “tanked” it is more “sectional tanked”— which is why it is generally known as cementitious waterproofing.

This system can withstand high water pressure and it most suitable for complex structures, where space is limited and does not require the installation of a pump system.

before basement waterproofingafter basement waterproofing

Before & after photo of cementitious waterproofing.


We provide a 10 year guarantee with this installation.

Membrane is fitted to walls/floors using specialist fixing plugs incorporating perimeter drainage channels which leads to an exterior outlet. If there is high water ingress then a sump chamber & pump system is also installed to divert running water via the pump system and then onto an exterior outlet. The chamber is designed to excavate water collected from the installed cavity membrane system. This chamber is placed into the floor at slab level to allow for collected water and to prevent dewatering below this level. This chamber is placed usually in an out of sight but accessible area (some clients have them placed within a cupboard floor/corner section of hallway, etc.)

A flat lid is then placed over the chamber and can be incorporated within floor coverings to allow for easy access for when a service/maintenance check of the internal submersible pump needs to be carried out. Very similar to having a manhole cover that needs to be accessible but is out of the way.

Walls can then be dry lined with an independent frame system, then plasterboard applied and finally a skim plaster finish. Screed or chip-board can be applied to the floor.

The prime advantage of cavity drain membrane is due to the independent frame lining system decorating can be carried out straight away, can be applied to painted surfaces and allows pipes/electrics to be hidden behind the system.

basement waterproofingbasement waterproofing

Sump & Pump System

The sump chamber is manufactured from high density polyethylene and is designed to resist ground water pressure. Either one or two pumps are then fitted. The sump chamber is fitted with two brass non-return valves to prevent water travelling back into the chamber once the pumps have stopped and a gate value for isolation for maintenance/servicing purposes.

Get in Touch

Office hours:

Monday to Friday, 9am - 5.30pm

(Closed on public holidays)

When the office is closed an answerphone service is available.

Office address:

8 Jasmin Road,
KT19 9DZ


Office: 0208 714 5002
Mobile: 07809 207461
Email: info@jbdampproofing.co.uk