Dual Seal Waterstop is a Bentonite based waterstop which reacts in contact with water by swelling to form a watertight seal in concrete structures. Dual Seal Waterstop has been independently tested up to 30 metre head of water, it has full WRAS approval for use with potable water.

Dual Seal Waterstop has been specifically designed to seal construction joints against the ingress or outgress of liquids in water retaining or excluding structures. Dual Seal Waterstop is fixed by nailing to the face of the existing pour prior to placing the next pour. It is installed directly onto scabbled surfaces and will swell into voids up to 12mm deep. Changes of direction and end joints are simply achieved by butting together, no welding or adhesives are required.

Dual Seal Waterstop can be applied to green concrete and in damp conditions.

7mm x 25mm – Supplied in 8 metre rolls.

Physical Properties Value Test Method
Colour: Grey/White
Pliability: 180° bend over 2.5 cm mandral @ -32°C 1000 ASTM D146
Tensile strength 44.8N/mm2 ASTM D412
% Elongation – ultimate failure of membrane 600% D638 Type 4
Resistance to water migration No migration at 31 m head
Water migration at or through joint None
Permeability through membrane 0.001 Perm
Installation Temperatures -20°C to +60°C
Operating Temperatures -43°C to +132°C
Life Expectancy Longest life expectancy of all organic membranes
Toxic/Staining None
Freeze/thaw and wet/dry cycles No affect
Cycling over 38mm joints No deterioration 2000 cycles
Salt Water Grade available for use when salt content exceeds 2000p.p.m.