Located in the heart of London’s insurance district, 40 Leadenhall in EC3 is not only one of the largest office developments completed in the capital in 2024, but also a landmark project symbolising the future of sustainable commercial architecture.
Project developers Proteus Waterproofing, working in collaboration with ARC Waterproofing Ltd, supplied and supported the application of advanced, sustainable flat roof and terrace waterproofing solutions across 5,380m² of roof space on the North Tower, South Tower and the restored Grade II-listed Billiter Street.
Multiple roof levels, a large footprint and an extensive number of terraces presented considerable technical and logistical hurdles. These included significant variations in terrace layouts and roofing zones, the need for phased installation with constant area transitions and strict environmental, safety and scheduling requirements.
Proteus and its approved contractor worked alongside Proteus’ in-house Technical Design Team conducting detailed U-value calculations to meet thermal requirements. Co-ordination was essential throughout the project due to the varying sequence of works, complex logistics and high-rise installation challenges.
This collaborative approach ensured the waterproofing works met the project’s exceptional design, environmental and performance standards.
Employing Proteus products – Cold Melt®, Proteus Hot Melt®, Pro-Living® and Proteus Pro-Therm – it was possible to exceed thermal performance standards, eliminate environmental compromise and deliver robust green roofing solutions across a structurally and logistically complex site, integrating eco-conscious waterproofing and insulation systems.
From heritage integration to environmental excellence, this project showcases how innovative waterproofing and insulation systems can contribute significantly to building longevity, occupant wellbeing and environmental stewardship.
