BriggsAmasco completed a complex, multi-roof waterproof installation as part of a huge mixed-use development in the heart of London.

The multimillion pound project in Charlotte Street, located near the BT Tower in the bustling central part of the capital, includes much-needed affordable housing and a raft of retail and office buildings to form a vitality-filled social-economic hub.

Designed by leading architects Make, and delivered by construction firm Multiplex, the nine-storey, £180m development achieved BREEAM ‘Excellent’ at the design stage for its litany of sustainable features. These include roof-based air source heat pumps for heating and cooling buildings without the need for traditional carbon-intensive gas boilers. Solar thermal panels have also been installed throughout the development to reduce grid electricity use. Such energy-saving initiatives were designed to ensure the project achieved 28% lower embodied carbon intensity than the Royal Institution of Chartered Surveyors (RICS) benchmark.

The thermal performance of building elements such as terraces was also crucial to the development’s overall environmental credentials. For the commercial block, it led to contractors enlisting BriggsAmasco’s expert waterproofing services being entrusted with the challenging task of installing high-performance insulation to a number of terraces differing in size and complexity. The initial work involved the installation of an Alumasc Hydrotech hot-melt waterproofing system and its partner’s Kingspan high-performance insulation.

Due to the terraces’ differing levels, BriggsAmasco’s engineers had to ensure the waterproofing build-up created a uniform height in order to limit the risk of trips and falls, as well as upholding the building’s aesthetic. Paving slabs and timber decking provided the terraces’ waterproofing finish. Due to the constraints in which BriggsAmasco’s teams were working it was a requirement at door thresholds to adapt the system and develop the bespoke design that was measured in millimetres. Rubber matting was also provided as a protection layer prior to the installation of the finishes.

In total, the Charlotte Street redevelopment, which was completed in June 2020, comprises 322,000ft2 of office space; 43,000ft2 of residential units, including 10,000ft2 of affordable housing. 12,000ft2 of retail outlets and a new public realm park. Thanks to the diligence and skills of BriggsAmasco’s installation team and despite the challenges faced, the terraces’ waterproofing was delivered to the agreed timeframe and the client’s full satisfaction. It meant an important element of this superb city development has been long-term protected against the elements and contributed to the buildings’ as-designed thermal performance.



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Hotmelt: Alumasc Hydrotech