A client in Bradford contacted Damptec Systems Ltd to design and install a tanking system to resolve the issues with water entering a lift pit. The previous contractor had put an asphalt material on the walls and floor and due to hydrostatic water pressure this had lifted in places.
We investigated the site and noted that the damp proof course positioned just above the structural slab was creating a passage through which water could track.
Carl Weatherhead, CSSW, proposed a Type A: Barrier Protection system in the form of internal negative waterproofing as detailed below.
Specification
Prior to our arrival on site the surfaces were made structurally stable, cleaned, dried and were free from release agents, dust, laitance, oils, paints or other forms of contamination.
The blockwork walls required surface preparation such as scabbling, to ensure all surface contaminants were removed to allow us to achieve a good ‘key’.
Damptec carried out the following waterproofing repairs on the negative side:
- Grind out DPC and repair using Koster Repair Mortar.
- Concrete floor and walls to be primed with Polysil TG 500.
- Form a fillet along the wall/floor junction and the vertical change of direction junctions using Koster Repair Mortar Plus.
- Apply Koster KD system
Koster KD Systems
The system consists of 3 products:
- KÖSTER KD 1 Base – fast curing mineral sealing slurry with excellent resistance to aggressive ground water and high water pressure.
- KÖSTER KD 2 Blitz-powder – highly reactive powder with extremely short setting time. With application of the dry powder, active water leaks are sealed within seconds.
- KÖSTER KD 3 Sealer – extremely low viscosity silicifying liquid. The active ingredients penetrate deeply into the substrate and react to form an insoluble compound. The pores are plugged and permanently sealed through the mineralization process.
- Immediately afterwards and again after approx. 30 minutes, repeat step 1, (application of the KÖSTER KD 1 Base)