Overview

Delta Registered Installer, Oaks Damp Proofing Co, provided waterproofing design and installation for the redevelopment of a warehouse in London into residential spaces. The 3,000 square foot structure required the renovation of an existing basement and back of house comms areas to offer 107 dwellings.

Delta’s Technical Team offered advice and guidance throughout the project. Working with the architect, main contractor and client, Delta’s robust design was tailored precisely to requirements.

Methodology

A Type C waterproofing system was selected as a maintainable solution to the existing basement to ensure a Grade 3 habitable environment was achieved.

A Delta Type C waterproofing system was considered the most reliable and maintainable approach. In principle, a cavity-drained waterproofing solution allows moisture or running water to travel behind the membrane within a controlled drainage system. A cavity-drained system requires minimal preparation and disturbance to an existing substrate.

Due to a lack of head height, and options being limited on not raising ceiling levels or lowering floor levels, to maximise space a complementary system of Delta’s PT 3mm membrane, FM membrane and Koster VAPlite was specified.

All construction joints were sealed prior to the installation of the Type C system. Due to the nature of concrete, structures are often constructed in divided sections using joints. The key function of sealing joints prior to the application of the waterproofing solution is to create a secure waterproof barrier and to minimise potential structural weak points which allow for water ingress.

Using Koster Repair Mortar Plus, Oaks created coved fillets at the soffit/wall and wall/floor junctions. Coved fillets help in lowering stress concentration and help to protect this vulnerable area from water and moisture penetration.

Perimeter drainage channels were sited within rebates in the basement floor, allowing for suitable drainage of any water ingress being diverted to suitable discharge points; in this case two of Delta’s V4 sump pumps.

Oaks applied a layer of Koster NB1 prior to an application of Koster VAPlite over the entire floor area. Koster VAPlite is a one-coat, membrane-forming, moisture vapor control system consisting of a unique combination of epoxy resins and other compounds formulated to prevent floor covering failures on concrete slabs with elevated levels of moisture. An application of Koster SL Premium completed the waterproofing system to offer a stable, hard-wearing and trafficable surface.

Before installation of the Delta Type C membranes, all new concrete was treated with Koster Polysil TG 500 anti-lime inhibiter to seal the surfaces and reduce the leaching of ‘free lime’ which could cause blockages behind the membranes.

After the Type C system was installed the all-important integrity testing was undertaken to exercise the waterproofing system in a worst-case scenario.

Result

Oaks Damp Proofing worked with Delta’s Technical Team to ensure both design and installation were seamless.

The basement is fully protected against the long-term threat of water and damp ingress.