Tunelling marathon deep beneath the streets of London



Soprema Group have always been at the forefront of innovation. Since 1908, Soprema have manufactured waterproofing membranes for a vast range of applications; from flat roofing to underground construction projects and basements; surfacing to drinking water reservoirs, canals and dams.

Over the past 50 years, Flagon membranes have been used to waterproof some of the World’s most celebrated structures, including many prestigious underground railway tunnels. Today, Soprema are one of the World’s leading manufacturers of synthetic membranes for waterproofing major civil engineering works.


The Soprema Flagon Tunnel Waterproofing System has been specified and installed on numerous underground projects across London. With key clients including Crossrail, TFL and London underground, Soprema have gained invaluable experience in delivering tunnel waterproofing systems.

Designed on a project by project basis with a 120 year design life, the supply chain and designers have faced many challenges throughout many of the tunnelling projects, resulting in the development of new details and bespoke designs. Ultimately, these innovations have increased efficiency on subsequent projects. Every underground project has continued to develop further knowledge and confidence in the Soprema tunnel waterproofing system amongst project designers and project stakeholders.


Soprema guarantees faultless waterproofing by working closely with the project designers and managers from the early stages of the project right through to completion. The waterproofing system consists of various materials for sealing, draining and protecting, whilst also facilitating inspection and repair possibilities both during and after construction. The correct installation of the products by qualified applicators is essential and regular inspection and quality assurance are vital to ensure a fully functional system.




C305 Stepney Green Caverns, 5000m2

C300/410 Fisher Street Shaft, 2000m2

C305 Running Tunnels, 2000m2

C310 Thames Tunnel, 2000m2

C360 Mile End Shaft, 2500m2

C360 Eleanor Street Shaft, 7000m2

C510 Whitechapel Station, 36000m2

C510 Liverpool Street Station, 38000m2


Vauxhall Station Passenger Tunnels, 3000m2

London Underground

Victoria Station Passenger Tunnels, 10000m2

Victoria Station Shaft PAL 2, 2000m2