ULTRA External Waterproofing System

ULTRA Type A protection comprises of an externally applied system which incorporates serviceable external drainage around the perimeter below the internal floor slab level. The external drainage should then lead to a soakaway which is capable of working in all groundwater conditions or to a mechanically pumped system. 

Type C Cavity Drain System
External basement tanking

Typical Installation Detail

Waterproofing a basement internally



External waterproofing is typically used in new build construction. It is possible but often difficult to waterproof existing basements.


Superseal Plus Liquid Membrane has been applied as a primary waterproofer, prior to the installation of ULTRA GEO cavity membrane in conjunction with ULTRA Land Drain around the perimeter. 


N-Virol Fillet Seal provides a waterproof seal around the wall to floor construction joint.


It is important to ensure the land drain is fully maintainable as this can lead to failure in the waterproofing system.

Waterproofing the exterior of an existing basement is often very difficult, impractical or impossible. However, new-build structures that are earth retaining are susceptible to water ingress caused by hydrostatic pressure.


Other factors including high water tables, perched water tables or even neighbouring construction projects may alter the path of water at some point in time. It is therefore imperative that basements should be protected from water ingress at the design and construction stages.


We can offer our ULTRA GEO membrane system which is designed for external use in conjunction with a suitable maintainable land drain (to comply with BS8102).