Advance Property Preservation Limited were approached to offer a waterproofing solution for a large new build, single storey structure with basement which would offer both residential and commercial use to a development in West London.

The basement walls were high power pressure washed prior to an application of Delta Membranes Systems Koster Polysil TG 500, an anti-lime inhibitor.

With two coats of Koster NB 1 grey being applied to the retaining walls which was lapped to the ceiling and floor slab.

Koster NB 1 with its crystallizing minerals were employed to seal against pressurized water (> 13 bar) and is classified as a Type A (Barrier waterproofing) System.

This mineral coating waterproofing slurry contains capillary-plugging agents making it an ideal solution to protect the structure from ground moisture ingress, for nonpressurized and pressurized water.

For phase 2, a combination of a maintainable modular/ sub slab and perimeter drainage system was incorporated into the ground bearing basement slab in association with the Cavity Drain Membrane System and the basement floor was levelled to no more than 1-10mm.

48 Linear Meters of Delta Drainage Channel was incorporated into the basement floor area of the project, accumulating to 250 m2.

The access ports to the Delta Channel were included at regular intervals for future maintenance purposes, a vital aspect of internally applied Type C Cavity Drained Membrane Systems to keep running to their optimum.

120 m2 of retaining walls to the structure were linked to the Drainage System to ensure any weak points (floor/wall junctions) were adequately protected rom any potential water ingress.

To finalize the twin waterproofing system, Delta MS 500 membrane was applied to the basement walls and Delta MS 20 membrane was applied to the basement slab.

A Type C Cavity Drain system is made up of cuspated membranes which are applied to the walls and floor of a basement with a channel incorporated at the wall/floor junction.

The cavity drain membrane allows any water ingress to filter down to the slab and find its way to the perimeter channel.

Each channel directs any water ingress to a sump pump or agreed drainage points which is situated below the slab (floor). The sump pump chamber will then remove any water ingress to the ground level drains.

The lower internal, non-earth retained walls received a DPC (damp-proof course) to act as a barrier through to prevent moisture rising by capillary action such as rising damp. The DPC was linked to the Type C system ensuring the structure was protected.