Basement Extension to a Grade 2 Listed Building, London

Built in 1855 as an Elizabethan School for local children, the historic and landmark Castle Club has also been a children’s hospital, youth club and private residence in its long history.

Since being acquired by property developers Thackeray Group however, the Grade II Listed building is now to be converted and extended as a specialist care home.

The work includes not only the restoration of the historic gothic structure, but also the building of a modern four-storey extension to the rear, including a 5,000 square foot basement extension.

The Project

Newton worked with UK super-prime construction experts Knowles Construction as the main contractor, alongside Thackeray Group and Darling Associates Architects.

The 5,000 sq/ft basement, linked to the existing structure, was excavated using secant piles, with a raft foundation, and perimeter RC liner walls and retaining walls for the structure, which needed to be completely dry as per BS 8102:2022.

The Solution

As the designers of the waterproofing solution, Newton's design team proposed a combination of Type B and C waterproofing systems as per BS 8102:2022 to deliver a dry environment.

Firstly, Type B products from the Newton HydroTank System were used to ensure that the concrete structure is itself integrally waterproof. The first of step was to install the resin injection waterbar, HydroTank 302 Injection Hose, to all construction joints. With ports every 10 metres, the hose is injected with a specialist resin after curing, which penetrates into the concrete to permanently seal any gaps and voids.

Whilst no additional ‘waterproofing admixture’ is required, HydroCoat 104 Super, an active crystalline coating, was applied internally to protect against the movement of moisture through capillaries and hairline cracks in the concrete.

Pipe and service entries were also protected with specialist Hauff-Technik Press Seals to seal any structural penetrations.

Lastly, for complete peace of mind, the Newton CDM System provided the internal Type C waterproofing solution, and the most failsafe and reliable form of waterproofing protection.

The maintainable and effective system combines BBA approved cavity drain membranes with bespoke sump and pump configurations, backup systems, telemetry and ancillary options to create a system that depressurises ingressing water before safely managing and removing it from the structure.

The Result

The partnership between Newton Waterproofing Systems and Knowles has helped to deliver this beautiful Listed project, as well as a new dry basement that will benefit the residents of the new care home in Fulham.

We are proud to have been involved in the regeneration of this rich heritage site, turning it into a building that will continue to be used for generations to come.