Basement waterproofing system protects luxury housing development from ingress

A Delta Membranes basement waterproofing system has been used to manage and control water ingress at a luxurious residential project in St John’s Wood, London.

Designed by Greenway Architects, the development incorporated a double level basement, with the lower level extending out underneath the garden.

Contractor Knowles & Associates undertook the following works in regards to the below ground structure:

• Excavation and formation of a basement
• Two/three stage underpinning
• Internal steel staircase frame
• Piling
• Mass excavation to spoil
• Construction of rear extension
• Below slab drainage
• Cavity drain waterproofing
• Insulation and screed
• Swimming pool shell within lower level basement

Waterproofing the basement

To waterproof the below ground structure, the Delta System 500 ‘type C’ waterproofing system was installed to deal with any water ingress. The system comprises Delta MS500 fixed to the walls and Delta MS20 laid across the floor, sealed with double-sided tape and Delta corner strip tape.

Modular drainage was installed to drain any water build up to a bespoke Delta packaged pump station, which was situated within the RC concrete slab on the lower level basement. The bespoke dual groundwater and surface water sump pump is capable of pumping 1.8l/s, with a total storage capacity of 653 litres.

The pump station collects ground and surfaced water from the basement walls, floor and external light wells. A separate foul pump station was also installed, to deal with the foul facilities within the basement. 

Koster Deuxan 2C was applied to the topside of the soffit, reinforced with a glass fibre mesh, to waterproof the basement lid of the lower level that extends out underneath the garden.

Delta Membrane Systems,
Delta House,
Merlin Way,
North Weald,
Epping,
Essex,
CM16 6HR
United Kingdom

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