Tanking a reinforced concrete lift pit

HomeTanking a reinforced concrete lift pitTanking a reinforced concrete lift pit

This lift pit in Coalville had already been constructed.  Black Jack bitumen paint had unfortunately been applied to the lower section in an attempt at stopping an active leak. This had failed and the construction company called us for advice and urgent remedial treatment.

Damptec Systems Ltd supplied and installed the following tanking system for waterproofing a reinforced concrete lift pit.

Type A: Barrier Protection – an internal negative tanking system

Internal: Type A (Barrier Protection)

Type A: Barrier Protection – an internal negative tanking system has been proposed:


This detail should be used where the requirement is to waterproof a reinforced concrete lift pit.

Internal: Type A (Barrier Protection)

Enabling works

  1. Cut a grove into the masonry exposing the Damp Proof Course to allow us to seal the joint using Koster Repair mortar plus.
  1. Prime the floor ready for waterproofing using Polysil TG 500.
  1. Due to the condition of the structural slab, install Koster Sewer and Shaft mortar to the base to create a solid foundation for the waterproofing. Allow to cure.

Proposed Method in Accordance with Koster Waterproofing systems


  1. Concrete floor and walls primed with Polysil TG 500.
  1. Form a fillet along the wall/floor and the vertical change of direction junctions using Koster Repair mortar plus.
  1. Apply Koster KD system

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 Blitzpowder 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.

Method of Application: Brush

Where services (pipework etc.) protrude through the system at the time of installation create a seal using either waterseal rope or mastic.

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