Preservation Treatments were asked to provide a design for a waterproofing system to an unusual building, built into a sloping site in North London. Our remit was to provide a system that complied with BS8102;2009 Grade 3. As the property was being constructed under the guidance of an independent insurance company, we also had to consider Chapter 5.4 (Waterproofing Basements and other Structures Below Ground)
In this instance, we started with a Delta Cavity Drain System, as we had the opportunity to allow any moisture to drain down through the multi-level sub-ground levels of the property to a land drain. However, Chapter 5.4 suggests that waterproofing should be carried out using a minimum of two forms of waterproofing, so we used a waterproof Crystalline Slurry (Koster NB1) prior to the application of the Delta Cavity Drain Membrane. This worked particularly well, as the slurry reacts with the new re-enforced concrete to form a waterproof barrier even before we started applying the Cavity Drain Membrane.
We worked closely with the Product manufactures throughout the process, as we had a few barriers to cross. There are always variances to the original build. In this instance, the Lift Shaft was relocated after the main retaining wall had been built, meaning a change in specification. Whilst not ideal, we were able to provide an alternative solution that still complied with the aforementioned British Standard.
We carried out the work to the retaining walls and sub-structure over a 5-week period, returning to the property to apply waterproofing to the lift pit which had been open to the elements at high level.
The client was then able to complete construction and apply finishes to the walls using Plasterboard Linings on a Gyproc metal frame, allowing the walls to be insulated and any pipework/cabling to be hidden behind the linings.
As you can see from the pictures, the end result is a beautiful property finished to a very high standard. Our clients are looking forward to working with us again on future contracts, where we hope to be of assistance.