Basement waterproofing for a residential home in Chelsea


Client: Donovan Construction

Products Used: Delta Kosher repair mortar, Delta Kosher Ploysill TG500, Delta Kosher NB1 slurry and Delta Kosher Deuxan 2C waterproofing liquid membrane.

Timberwise were contacted by Donovan Construction to design and implement a basement waterproofing solution for a home they were in the process of building. The newly-built home was to be quietly situated in Chelsea and intertwined between the handsome red brick buildings in the area, in a quiet and pretty residential street located immediately to internationally renowned shopping and restaurants of the Kings Road and Fulham Road.

As the basement is below ground Timberwise Waterproofing Design Specialists had to assume that it would be affected by groundwater penetration and consequently the waterproofing design had to be appropriate and the treatments specified had to protect the basement against the potential risk of water penetration

The structure of the basement was of waterproof reinforced concrete construction with external waterproofing and drainage to the upper deck area. Internal basement waterproofing had also been specified to protect against any groundwater ingress that could occur for various reasons.

With London, in particular, Kensington and Chelsea, seeing a sharp rise in basement conversions over the past decade these ‘Iceberg homes’ astonishing amenities including home cinemas, garages and swimming pools. The new basement construction was intended for domestic living accommodation so any waterproofing specification had to reflect this.

Did you know?

The King’s Road, named after Charles II, was built to connect his palace in Whitehall to Hampton Court. By the 1960s, Chelsea and, in particular, the King’s Road, became the centrepiece of mod culture and the Swinging Sixties in the UK. It was often frequented by cultural icons such as Twiggy and Andy Warhol.

Timberwise Waterproofing Design Specialists refer to the environmental grades and defining performance levels as set out in British Standard 8102 – Code of Practice for Protection of Structures Against Water from the Ground, set out below: Following the guidance of BS8102 Timberwise advised that a waterproofing solution capable of delivering a grade3 environment should be allowed for and therefore designed, specified and quoted for such a waterproofing treatment.

Fantastic project! The integrity of this building lies in our hands, and we’ll do everything to make sure its a safe and dry for the future

Keith Defoe, Waterproofing Specialist

External Waterproofing

Flood testing was carried out to the upper concrete screeded deck to establish that the installed drainage falls were effective and that drainage to the sump chamber was operable. External waterproofing was carried out using Delta Kosher repair mortar, Delta Kosher Ploysill TG500, Delta Kosher NB1 slurry and Delta Kosher Deuxan 2C waterproofing liquid membrane. A Visqueen slip layer was installed along with a cavity drain and protection layer to the Deuxan waterproofing.

Basement Waterproofing

Inside the basement, flood testing was carried out to the basement floor to establish if the installed floor slab was free from low/high spots. Delta Kosher Polysill TG500 was applied to the concrete floor slab to ensure no future problems of lime-scale blocking up the drainage.

Delta MS500 Cavity Drain Membrane was curtain hung on the walls to full height, along with the installation of Delta drainage channel that was connected to a pump chamber. The perimeter drainage channel also included inspection ports to allow for future maintenance of the waterproofing system. The waterproofing installation was then finished off with fully bonded 90mm Foamglas insulation and Delta MS20 Floor Membrane.


Timberwise were tasked maintaining the property’s true potential with a basement waterproofing solution. Once the house was completely finished, the basement became a home cinema making for a relaxing and comfortable place to unwind, with enough room for numerous people to relax and enjoy the newly installed sound system and flat screen TV.

Contact Our Basement Waterproofing Contractors

All our basement solutions also benefit from our design and installation services along with our long-term insurance backed guarantees ensuring you have complete peace of mind that your basement will remain dry for the year to come.

You can trust Timberwise to provide you with the right basement waterproofing systems to solve your damp basement problem. Don’t hesitate to contact Timberwise via our form above, by calling on 0800 288 8660 or you can request a survey online.

A survey through Timberwise will allow our waterproofing contractors to be able to identify the full extent of the problem and determine whether further basement solutions may be necessary for your property.

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