Foundation Slab Waterproofing System


A complete waterproofing system in new construction includes waterproofing the floor slab. Compared to the application on top of the concrete slab the installation of the waterproofing layer underneath the foundation keeps the foundation dry and the concrete provides a better thermal insulation.

Firstly, a primer such as KÖSTER Polysil TG 500 is applied to the clean, sound and solid substrate. This is a standard primer that locks existing salts into the substrate, hardens the substrate and provides a better bond between the waterproofing and the substrate.

The main area of waterproofing made of KÖSTER Deuxan 2C is applied in two layers with KÖSTER Glass Fibre Mesh embedded in the fresh first layer. It is generally recommended to embed the KÖSTER Glass Fibre Mesh between layers as it provides an easy control of the layer thickness and absorbs the forces created by movement in the building. Before pouring the foundation plate, PE-Foil is installed in two layers to act as a gliding layer between the waterproofing material and the concrete. The waterproofing layer needs to be protected by a layer of unreinforced concrete. The vertical waterproofing is connected to the horizontal waterproofing layer which extends beyond the footprint of the slab.. A fillet made from KÖSTER Deuxan 2C or KÖSTER Repair Mortar Plus is to be installed in the connection area.

System Components:

  • Primer: KÖSTER Polysil® TG 500.
  • Waterproofing layer: KÖSTER Deuxan® 2C Extratight.
  • Embedded mesh: KÖSTER Glass Fibre Mesh.
  • Gliding Layer: PE foil.
  • Fillet: KÖSTER Deuxan® 2C Extratight and KÖSTER Repair Mortar Plus.
  • Protective layer: KÖSTER SD Protection and Drainage Sheet.

General information


E60/130 Precast slab

E60/140 Precast floor plate

E60/30 Precast slab

J30/110 Cold applied tanking . . . . . .

Specification data

Product Reference

Foundation Slab Waterproofing System

Product Options

Waterproofing layer:

- KÖSTER Deuxan® 2C Extratight:

Two-component, compression-proof, elastic, polymer modified, fibrated bitumen thick film sealant for safe waterproofing of buildings in accordance with DIN 18195. Resistant to pressurized water, approved by the building authorities. Radonproof.


Third party certifications

  • KIWA: Test Report 1998-14-4679/01N : Deuxan 2C Extratight tested in accordance to DIN 18195

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