Delta Registered Installers, Bensleys provided a waterproofing solution on an iconic Brighton structure.

Steeped in history and thought to be built on the original Brill Baths site, sits Clarendon Mansions.  This large, detached structure is thought to have been built in 1870 by Charles Brill during the Brighton boom.

The four-storey building facing Brighton’s famous sea front, was originally constructed as a hotel.

Numerous refurbishments over subsequent periods of time, saw the structure move from a hotel to a public house, with the basement area being unoccupied for nearly a decade.

The basement area boasts large, vaulted areas to the south and west elevation, with the south-side possibly being part of the original Bath structure.

Bensleys were instructed by the main contractor, Pilbeam Construction on behalf of Evolution Architects, to help design, specify and install the waterproofing system.

There’s no one-size-fits-all when it comes to waterproofing design.  With the basement suffering from water penetration, Bensleys worked with the design team at an early stage of the project to ensure the right approach be taken, which included multiple factors such as: customer requirements, standards, robustness, cost, resources, time, skill required, safety and expectations of ground water which all translated into a design solution.


Whatever method of waterproofing is used for retrofitting a basement, it should be appropriate for resisting ground water pressure and the product used should have British Board of Agreement (BBA) or similar independent technical accreditation.

The waterproofing design was compliant with British Standard 8102:2009 2009 ‘Code of Practice for Protection of Below Ground Structures Against Water from the Ground and practicable for future maintenance. The project required Grade 3 protection – No dampness or water penetration acceptable.

Bensleys recommend a Delta Type C cavity drainage waterproofing solution.  Delta Type C cavity drainage systems are considered one of the safest and most reliable forms of waterproofing.  Delta Type C cavity membranes are textured. breathable membranes which are installed to the entire inside of a basement.   Part of this ‘controlled system’ is basement drainage.  As water ingress penetrates the basement, all water ingress is directed into perimeter drainage channels which this then efficiently disperse to sump pump stations. Once collected in the sump pump chambers, the water ingress then pumped to a suitable evacuation point.

Once the structure was fully prepared for installation of the Delta Type C system.  Delta MS 500 cavity drain membrane system was installed, extending to include the extensive vaulted areas, including a recess walkway which was designed and constructed by Pilbeam Construction.

Bensleys incorporate three Delta V3 Twin Pump stations with PowerMaxx22 battery backups and AlertMaxx2 WIFI enabled high level water alarms.

With the drainage system being supported with the AlertMaxx2, a sophisticated monitoring system that not only detects high water levels within pump sump chambers, but also monitors the pump stations performance, running regular health checks on the pump stations in a non-invasive way to monitor and troubleshoot electrical/mechanical failures before the occur.

The AlertMaxx2 is supported by the PowerMaxx2 ensuring a continuous power supply should there be mains failure.

Locations of the sump pump stations were suggested during the design phase.

Type C waterproofing will deliver a completely dry internal space, whilst also causing the minimum amount of disruption to the structure.

Case Study Results

Built under permitted development, the construction has been a real hit with the client.

The property will remain fully-protected against the long-term threat of water and damp ingress and will undoubtedly see a whole new era of transformation in years to come.

The ground and basement area will eventually be in use as Friday Ad HQ offices when they relocate from Mid-Sussex.

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