2025
River Thames, near Weybridge
SIKA WATERPROOFING SOLUTION PROTECTS UNIQUE RIVER THAMES BASEMENT
PROJECT DESCRIPTION
Located on the picturesque D’Oyly Carte Island, nestled in the middle of the River Thames, a stunning private residence required a robust waterproofing solution to safeguard its newly constructed basement from potential water ingress caused by the surrounding river.
PROJECT REQUIREMENT
With the property entirely surrounded by water, it was essential to create a fully waterproof structure capable of withstanding high levels of hydrostatic pressure. The client and architect sought a long-lasting, high-performance solution backed by certified, proven systems. Logistics added a significant layer of complexity to the project. Access to the island was limited to a narrow pedestrian bridge, meaning all materials — including over 400 bags of waterproofing product — had to be transported by hand.
Likewise, waste material had to be manually removed, presenting a substantial physical challenge for the installation team. Additionally, extensive surface preparation was required to ensure optimal adhesion of the waterproofing system. Techniques such as bush hammering, jet washing, and vacuuming were carried out meticulously to prepare the substrate for the application.
PROJECT SOLUTIONS
Sika collaborated closely with specialist contractor Renderseal Ltd to create a bespoke waterproofing specification tailored to the unique demands of the site. The Sika® 1 Pre-Bagged Waterproofing System was selected as the ideal solution due to its high performance, long-term durability, and BBA certification.
The system — a fully pre-batched waterproof render and screed — was applied to both the walls and floor of the basement. This provided not only structural integrity but also a smooth, aesthetically pleasing finish suitable for a high-end residential environment.
To ensure full watertight protection, Sikadur Combiflex® SG was installed at all wall-to-floor junctions and around service penetrations. This flexible sealing system accounted for potential movement and ensured critical points were securely sealed.
Over a 10-day period, Renderseal Ltd successfully installed the Sika® 1 system, overcoming the logistical challenges with professionalism and efficiency. The completed waterproofed basement now offers long-term protection against water ingress in a highly demanding riverside location.
The client received both a 10-year company guarantee and a Sika Manufacturer’s Warranty, ensuring total peace of mind.
"The basement in the middle of the River Thames is a perfect demonstration of the Sika-1 Pre-Bagged Waterproofing System. It provides high-performance waterproofing in a very wet environment — especially when installed by an experienced contractor." Terry Blackabee, Director, Renderseal Ltd
Project Participants
Owner: Private Client
Contractor: Renderseal Ltd
Market sector: Residential
Sika Products: Sika 1 Pre-Bagged Waterproofing System, SikadurCombiflex® SG