Coating FAQ

  1. Can paint and other finishing materials be applied over a Xypex coating? READ
    Yes. In most circumstances paint, epoxy coatings, cement parge coats, plaster and stucco can be applied over a Xypex coating. For further information concerning the interface of the Xypex coating with paint and other finishing materials, consult with a Xypex Technical Services Representative.
  2. Can the Xypex coating be applied to the negative side of a structure? READ
    Yes. Although applied as a coating, Xypex is not relying on its surface bonding capability to achieve its waterproofing effect. By means of diffusion, the reactive chemicals in the Xypex coating migrate through the capillary tracts within the concrete to become an integral part of the concrete mass. Therefore, the Xypex coating can be applied to either the positive (water side) or negative side even against strong hydrostatic pressure.

  3. Can the Xypex coating be applied while the concrete is wet? READ
    Yes. In fact, the concrete must be wet or moist before applying the Xypex slurry coat. Xypex requires moisture to generate the crystalline growth in concrete. The presence of moisture is also necessary to ensure proper bonding of the slurry coat to the concrete substrate.

  4. How deep does the Xypex crystalline formation penetrate the concrete? READ
    The Xypex chemical reactions that initially take place at the concrete surface will continue deep into the concrete structure. Various factors affect the rate and depth of crystallization within the concrete. Some of these factors are: number of Xypex coats, mix design of the concrete, density, porosity, cement content, exposure to moisture and temperature. Independent testing measured the depth of Xypex crystalline penetration into a cast-in-place concrete block at 30 cm (approximately 12"). The test concrete sample was coated on the top surface with Xypex Concentrate and left outside the research laboratory in ambient temperatures for 12 months.

  5. How is the Xypex coating system different from other cementitious coatings? READ
    Most cementitious coatings are simply surface treatments and are totally dependent on maintaining a proper bond to the concrete surface. Such coatings usually incorporate a latex modifier which makes the coating less permeable and acts as a bonding agent for better adhesion to the surface. They are surface treatments only, and have the added disadvantage of limiting breathability of the concrete. They do not form crystals within the concrete substrate (contrary to what is sometimes represented) and are not effective when applied against hydrostatic pressure.

  6. Is the Xypex affected by temperature, humidity, ultraviolet and oxygen levels? READ
    When applied according to specifications, Xypex performs at 100% efficiency within -25°F to +265°F (-32°C to +130°) constant temperatures or within -301°F to +2786°F (-185°C to +1530°C) periodic temperatures. Humidity, ultraviolet and the oxygen level (oxidation) have no effect on a Xypex coating.

  7. Is the Xypex coating suitable for use on surfaces other than concrete? READ
    Xypex is totally compatible with the chemistry of concrete, whether poured-in-place, pre-cast or shotcrete. It is not suitable for application to cut-limestone, clay brick, wood, metals, asphalt or other non-concrete building materials.

  8. Is there a preference when choosing between the positive or negative side? READ
    Generally, it is recommended that the Xypex coating be applied to the positive side (water side), if accessible, so as to ensure maximum benefit. Therefore, new construction specifications almost always call for the use of the Xypex coating on the positive side (water side). If, however, the positive side is not accessible e.g. tunneling projects or rehabilitation of existing structures, the Xypex coating will be specified for use on the negative side against the hydrostatic pressure.

  9. Is Xypex resistant to aggressive chemicals? READ
    Based on independent testing according to ASTM C 267-77 “Chemical Resistance of Mortars”, the Xypex coating is not affected by a wide range of aggressive chemicals including mild acids, solvents, chlorides and caustic materials. Because Xypex is pH specific (not chemical specific) it will protect concrete from any chemical whose pH range is 3.0 to 11.0 constant contact, or 2.0 to 12.0 periodic contact.

  10. What are the installation advantages to using a Xypex coating system instead of membranes? READ
    The crystalline nature of the Xypex waterproofing system provides many installation advantages over traditional barrier products:

    1. Xypex does not require a dry surface; in fact, a wet surface is necessary.
    2. Xypex does not require dry weather to be applied.
    3. Xypex does not require costly surface priming or leveling prior to application.
    4. Xypex cannot puncture, tear or come apart at the seams.
    5. Xypex does not require protection during backfilling or during placement of steel, wire mesh or other materials.
    6. Xypex can be applied on either side of a concrete surface – the negative or the positive side.
    7. Xypex does not require sealing, lapping and finishing of seams at corners, edges or between membranes.
    8. Xypex is less costly to apply than most other methods.
  11. What is the appearance of a Xypex coating? READ
    A Xypex coating normally produces a grey-colored, cementitious surface. However, Xypex “White” is also available.