Type of Construction and Appropriate Crystalline Technology Application

Crystalline waterproofing and protection technology is available in powder form and is mixed with water. Three different application methods include:

• Applied to the surface of an existing concrete structure, for example, a foundation wall or a floor slab.
• Mixed directly with the concrete batch at the plant as an admixture.
• Shaken as a dry powder, applied to green, or uncured, concrete and toweled into the surface.

Methods and Procedures of Crystalline Waterproofing Coating Applications

When applied to clean, bare and previously saturated substrate as a slurry mixture, the reactive chemical ingredients in crystalline waterproofing can penetrate up to 12 inches deep inside the concrete by using the water as the migrating solution in a process of chemical diffusion. As these chemicals penetrate through the capillaries and pores, the reaction with the mineral by-products of cement hydration creates the crystalline formation that fills the cracks or the pore.

Crystalline waterproofing can be applied by a brush or with spray-on equipment. To ensure the success of the application, care must go into the conditions under which the material is applied related to surface preparation, surface wetting, coat thickness, and curing time.

Because the crystalline waterproofing coating system has a unique chemical diffusing characteristic, proper surface preparation of the concrete is critical to the performance of the material. The concrete surface that will receive the crystalline waterproofing coating needs to have an open pore texture to allow the transfer of the reactive crystalline chemicals from the coating into the concrete substrate. The surface also needs to be clean and free of form oil, laitance and other foreign matter as this can potentially cause de-lamination of the coating.

The three common methods of concrete surface preparation are water blasting, sand blasting and acid etching. When water blasting, the pressure should be 3,000 pounds per square inch (psi) to 4,000 psi. Sand blasting is normally required when steel forms have been used and the concrete has a tight, mirror like finish. Acid etching can be accomplished using either muriatic acid or citrus-based products when the use of an acid is not environmentally acceptable.

Wetting the Surface

The coating systems require that the concrete be in a saturated, surface damp condition for the waterproofing to be effective. The active chemicals in the coating use water as a migrating or diffusing medium that allows the chemicals to transfer from the coating into the capillary tracts of the concrete. To make sure that concrete on vertical surfaces is saturated, wet the walls with clean water and allow the moisture to be drawn into the substrate for approximately ten minutes. Re-wet the walls a second time and allow to stand for 20 minutes.

In hot weather, when evaporation rates are high, it may be necessary to soak the concrete overnight. This can be accomplished using either soaker hoses on the top of the wall, that allows water to flow down the vertical surfaces, or a series of sprinklers can be used if the wall is less than 12 to 15 feet.

If water is not readily available on the job site, the saturation of the concrete should be done early in the morning, when evaporation rates are low and before the concrete begins to heat up. In difficult conditions of hot sun and wind, it is better to attempt small areas that can be controlled, rather than large areas at one time. In hot weather, the use of an evaporation retarder to help keep moisture in the concrete can be considered.

In cold weather, saturation of the concrete should only take place when the ambient temperature is going to be above 33 degrees Fahrenheit for 24 hours.