Imperial Court Underground Car Park, Westminster

A waterproofing solution was required for the underground car park of a prestigious apartment building in Westminster.

The Challenge

Cast Contracting Ltd (CCL) were commissioned by Bolt & Heeks Construction to design, supply and install a comprehensive waterproofing system to the underground carpark at Imperial Court, used by residents of the luxury apartments above.The waterproofing works needed to be effectively installed within the challenging height restrictions of the underground car park and to strict deadlines.

The Solution

CCL recommended the use of a combined system due to the challenges presented at Imperial Court. CCL specified and installed Triton Platon P8 Cavity Drain wall membrane to all basement earth retaining walls.

Triton TT55 cementitious polymer modified waterproof coating was applied over concrete upstands at the base of perimeter walls and to the walls/soffit perimeter junctions. Triton Aqua Channel drainage conduits were then installed to the wall and floor junctions, with the purpose of collecting water and diverting it to the sump pump system.

Inspection ports were installed within the Aqua Channel to allow the system to be maintained. Triton Cornerstrip sealing tape was installed at the wall/soffit and wall floor junctions to completely seal the system.

To complete the works, two coats of Triton Triseal epoxy resin coating with an aggregate finish were applied to provide a non- slip finish to the concrete floor slab.To define the car parking bays from the drive through area, red and grey colour finishes were incorporated into the non-slip finishes.

Client Testimonial

“CCL were able to deliver a comprehensive waterproofing solution, and work within 24-hour shift patterns, including working through the night, in order to complete the works to our strict programme. Effective communication & accurate planning with the CCL contracts team & installers on-site ensured that all logistical requirements were achieved.”

Adrian Richards, Site Manager, Bolt & Heeks Construction

Products Specified

  • Triton Platon P8 Cavity Drain wall membrane
  • Triton TT55 cementitious polymer modified waterproof coating
  • Triton Fillet Seal
  • Triton Aqua Channel including Inspection ports
  • Triton Cornerstrip
  • Triton Triseal epoxy resin coating

Design | Supply | Installation

Cast Contracting Ltd (CCL) is the UK’s leading specialist in Design and Installation of all Waterproofing, Tanking and Ground Gas Systems across the United Kingdom. CCL prides itself on offering the highest level of service throughout the Design, Planning, and Installation process.

Structural Waterproofing & Ground Gas Solutions

CCL’s in-house design team can offer a comprehensive proposal for all scenarios in line with BS:8102 and BS:8485.

CCL Guarantees

One of the most comprehensive Guarantees across the industry, taking full project ownership.


Cast Contracting Limited is one of the longest standing industry specialists. As it is now part of the CCL Group of Companies, Cast Contracting Ltd has the additional stability and support with over sixty employees across the Group.

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