London, United Kingdom

For the transformation of commercial below ground coal vaults into modern storage spaces a proven waterproof system was required to eliminate the long-term threat of ingress.

Renlon specified Sika as the ideal solution.

Aberdeen harbour concrete project
Aberdeen harbour concrete project

Project Requirements

The underground vaults and external lightwells formed part of a terraced commercial property in prestigious Harley Street, Marylebone, London. Unusable due to the failure of a previous tanking system leading to water leakage, damp and structural damage, the building contractor required the areas to be converted into storage space.

Sika Registered Waterproofing Contractors, Renlon Ltd, carried out the refurbishment which initially involved the mechanical removal of the existing tanking system. With the vaults used to convey services such as gas, electricity and water throughout the property, the incumbent wall penetrations required a sealant flexible enough to allow for movement whilst remaining watertight. This was achieved using Sikaflex, a multifunctional sealant suitable for elastic, vibration-resistant joint seals.

Sika Solutions

For this project, a specialist waterproof system was required to eliminate the long-term threat of water ingress. Renlon Ltd specified Sika-1 Pre-Bagged Structural Waterproofing System, a multi-layer graded, precisely gauged and batched render based and waterproofing system. Comprising of watertight renders and a waterproof screed incorporating Sika-1 Waterproofing Liquid and Sika-1 Pre-Batched Mortars. The system is designed for optimum application, performance and durability.

Sikadur Combiflex, a high performance flexible waterproofing tape was applied with Sikadur  Combiflex Adhesive offer further protection at specific vulnerable construction joints, wall / floor junctions and arched soffit junctions.

This type of waterproofing system is also known as cementitious tanking, it is a specially formulated mixture designed to be applied on cellar or basement walls to stop the water passing through. In this case it was used both internally – on the walls, floor and vault – and externally – in the lightwell, giving extra protection from water ingress and seamless waterproofing solution.


Renlon Ltd has supplied the project with dry, commercial and modern storage spaces which will remain fully protected against the long-term threat of water and damp ingress and will certainly add value to the commercial property having now provided additional dry usable space.