Hydrophobic Mastic Waterstop for Concrete Construction

Mastic waterstop is a hydrophobic watertight product with similar appearance of butyl rubber waterstop but totally different natures. With single component of mastic, the waterstop will not expand and create any internal joint pressure when exposed to water, so minimal concrete coverage is needed during installation.

A coil of black mastic strip waterstop on the white background.
Black color mastic strip waterstop.
A coil of red mastic strip waterstop on the white background.
Red color mastic strip waterstop.

Features & benefits:

  • Excellent self-sealing and self-healing properties.
  • Applied in any weather and temperature.
  • Excellent adhesion to dry and clean surface.
  • Easy and quick to install.
  • Long service time without shrinking, hardening and oxidation over time.
  • Minimum clear cover is needed.
  • Suitable to be installed outside rebar to protect the steel form corrosion.
  • No harm to surrounding concrete.


  • Ideal for all non-moving joints.
  • Retaining or foundation walls.
  • Pipe penetrations.
  • Box culverts.
  • Vaults and tunnels.
  • Slab and manholes.
  • Storage tanks.
  • Any cast-in-place applications.

Not appropriate for moving joints.

6 mm × 25 mm, 15 mm × 20 mm, 20 mm × 30 mm, 20 mm × 50 mm, 30 mm × 50 mm, 10 mm × 40 mm or others as your request.


  • 15 mm × 20 mm and 20 mm × 30 mm: 25 meters / box
  • 30 mm × 50 mm: 10 meters / box

Your nominated types of packages are also available.


Physical properties Test method Results
Specific gravity ASTM D-71 1.22 to 1.41
Flash point ASTM D-92 450 °F
Fire point ASTM D-92 475 °F
Ash inert materials ASTM D-482 35%
Volatile materials ASTM D-6 1.20%
Five coils of black butyl rubber waterstops are packed with plastic film and cardboard box
The package of mastic waterstops