Basement Extension to a Grade 2 Listed Building, London

Summary

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  The modern extension will provide the rooms to deliver a top quality care home in the heart of London

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  The work by Newton and Knowles will help deliver the Castle Club back to its former glory

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  Modern architecture complements traditional Gothic styling

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  Knowles delivered the new below and above-ground structures

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  The original gothic style is retained on the Listed building

Built in 1855 as an Elizabethan School for local children, the historic and landmark Castle Club (a Grade 2 Listed Building) 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 contractor excavated the 5,000 sq/ft basement, linking it to the existing structure, using secant piles, a raft foundation, and perimeter RC liner and retaining walls, all designed to remain completely dry in accordance with 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 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 installed every 10 metres, the team injected the hose with a specialist resin after curing, allowing it to penetrate the concrete and permanently seal any gaps and voids.

Although the system required no additional waterproofing admixture, the team applied HydroCoat 104 Super—an active crystalline coating—internally to protect against moisture movement through capillaries and hairline cracks in the concrete.

The team also protected pipe and service entries with specialist Hauff-Technik Press Seals to seal all 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. This creates 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 played a key role in regenerating this rich heritage site, transforming it into a building that future generations will continue to use.