Water Repellents

Product Guide

For more information, see the Product Selection Guide.

Suggestions for water repellents include, but are not limited to, the following:

This section describes penetrating water repellents. If a membrane-forming acrylic sealer that produces a gloss or sheen is required, then refer to the Cure and Seal or Sealer section.
These water repellents are typically used to prevent or inhibit moisture penetration, attack by deicing salts and chloride ions, reinforcing steel and precast anchor corrosion, mildew and mold, attack by acid rain, spalling caused by freeze/thaw cycles, efflorescence and surface scaling.
These water repellents penetrate a concrete or masonry surface due to their small molecular size. Silane water repellents achieve the greatest depth of penetration because of the small molecular size. This depth of penetration is crucial for long-term performance of water repellents. It must be protected from the damaging effects of weather exposure and surface abrasion. The depth of penetration will typically be from 1/8" to ¼" (0.3 cm - 0.6 cm), depending on the density and porosity of the surface.
Previously applied membrane-forming curing compounds must be removed prior to application of the water repellent. Most curing compounds form a film on the surface that will prevent the penetration of the material.
Proper surface penetration by the water repellent is crucial to performance. Water repellents must be able to thoroughly penetrate into the substrate. This means all previously applied curing compounds, coatings, dirt, oil or other surface contaminants must be removed before application. Cleaning methods include shotblasting, sandblasting, high pressure water blasting and/or safe floor stripper.
A good method to determine if the surface has been sufficiently cleaned is to place a few drops of water in different areas on the surface. If the water is readily absorbed into the surface, then no additional cleaning is necessary.
The surface should be completely dry before application. A dry surface helps to maximize the depth of penetration of the water repellent. If the surface was wet, then allow a minimum of 24 hours for drying.
Most water repellents are applied to concrete at least 21 to 28 days old. The performance of these water repellents is reduced if applied earlier.
Substrate porosity can vary greatly, which changes the rate of application needed. Always apply a sample treatment in an inconspicuous area to determine necessary coverage rate. Allow samples to react 3-7 days, then conduct testing to verify that performance meets expectations.
The preferred application method is very low pressure spray (approx. 15 psi, 0.1 MPa). Use a fan-type spray nozzle. Mist spraying or high pressure spraying will only waste material.
The preferred time to apply water repellents to concrete and masonry surfaces is late in the day when the temperature and the structure to be treated starts to cool down and the wind tapers off.

Liquid Systems

Available in solvent or water-based formulations.

Cement Systems

Enhance concrete performance or correct problems.

Epoxy Systems

Resin-based systems correct structural concrete problems and protect concrete surfaces.

Polyurea Systems

Polyurea-based systems to repair and protect concrete joints and nosings, even in low temperature conditions.

Polyureas