Luxury new build basement, North London

26 July 2018


Basement type: Refurbishment Building type: Residential
Type of waterproofing: Type A & C Member: Delta Membrane Systems

The Project

This new build luxury property in North London provides almost 17,000 sq ft of accommodation, set over four floors. This spectacular mansion features marbled flooring, atrium hallway, several bedrooms, a home cinema, luxury spa, swimming pool, massage, nail bar and hair dressing salon, entertaining rooms, formal and informal dining rooms.

High volumes of hydrostatic water pressure was bearing on the structure, which was causing the property to suffer severe water ingress through construction joints. An additional problem was the property had been built without a waterbar/hydrophilic strip. A waterbar or hydrophilic strip will expand when a structure experiences water ingress, slowing down/stopping water ingress. It is good building practice to incorporate a waterbar/hydrophilic strip to any below ground structure.

The property when built incorporated a cavity drain membrane system (not Delta’s) and sump pump units. The rooms to the basement comprise: swimming pool area, spa, massage, nail bar and hair dressing salon, comms room, electrical intake room and maids quarters. The electrical intake room was flooded which raised a health and safety issues for the occupiers of the property and required immediate remedial action.


The project, due to its size and complexity was set into phases. The first phase was to ensure the property was made safe from electrical dangers. The second phase was to stop the water ingress. Once the structure had been stripped back to its concrete core, the water ingress to construction joints was addressed.

A waterbar/hydrophilic strip cannot be retrofitted, so an alternative approch was required. Delta recommended using the Koster brand of concrete repair solutions to limit and slow down the water ingress. Koster KD Blitz Waterstop, stops active water ingress and safely seals off pressurized water from the negative side. Once the construction joints were sealed, Koster NB1 and Koster Repair Motar Plus were used to add a secondary line of defence with NB1 coated to external walls throughout the basement structure to stop any water ingress.

Consideration was given to managing future water ingress issues. Delta recommended additional sump pump stations throughout the structure and PPS (Package Pump Systems Limited) were invited to explore options. Delta’s MS20 offered a solution to the floor design, with its 20mm stud it can deal with the volume of water ingress. 


The homeowners were delighted with the project and the communication and expertise of Delta. Delta's on site attendance and eye for detail were exactly what was needed for this project and the waterproofing system addressed the issues caused by the hydrostatic water ingress.

System Components

The project used: 

  • Koster KD 2 Blitz – waterstop
  • Koster NB1
  • Koster Repair Motar Plus
  • Delta MS20
  • Delta MS500
  • Delta AlertMaxx2- with its wifi capabilities would allow the client a monitoring system.
  • Delta Sump Pump Stations

 The client opted to subscribe to PumpAware allowing PPS to monitor the property 24/7/365.

See Delta Membrane Systems company profile