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Concrete Waterproofing Systems

Replaces traditional solvent-based waterproofing on foundation walls

Crystalline waterproofing penetrates several inches in concrete preventing moisture from seeping in.

Anyone who has had damage from water seepage knows that it is a costly and time-consuming process to repair. One way to help reduce water seepage is by using crystalline concrete waterproofing. This method uses a catalytic reaction to seal the pores, capillaries and shrinkage cracks that occur naturally in concrete. Crystalline waterproofing penetrates into the concrete.

Long available for industrial applications, crystalline waterproofing is now ready for use in residential applications. It consists of a dry powder compound of Portland cement, very fine treated silica sand, and proprietary chemicals. Combining the product with water and applying it to the surface of concrete results in a catalytic reaction that forms non-soluble crystalline fibers within the pores and capillary tracts of concrete. This seals the concrete against moisture penetration. Crystalline waterproofing replaces traditional solvent-based waterproofing on foundation walls. However, exterior parging or bituminous waterproofing, or a drainable layer may be required by the building code.

Water penetration through basement and crawl space foundation walls is usually caused by condensation or exterior water source, from inadequate grading, rainwater collection, or poor footing drains. The source of condensation or exterior water must be corrected prior to application of crystalline concrete waterproofing.


According to the manufacturers, it may be applied to the interior side of damp basement walls or on-grade slabs. The product is nonflammable and odorless, and it cleans up with water.

Quality and Durability

Crystalline waterproofing is known for its strength and effectiveness as waterproofing for reservoirs, sewage and water treatment tanks, and tunnels. Crystalline waterproofing can also withstand salt spray and some chemicals.


The material price for crystalline waterproofing averages about $0.40 per square foot, while installed cost can range between $1.30 to $2.50 per square foot, depending on number of coats and surface preparation. Maximum labor savings may be possible by using some products as an admixture added to the concrete mix, which is claimed to cost about $0.75 per square foot for an 8" thick concrete wall.

Not Applicable

A treated concrete product can be tested for compliance with the appropriate ASTM standards for strength, bonding, abrasion resistance, freeze/thaw, fungus growth resistance, and breathability. If building code approval is not available, it can be used in combination with approved methods. Building codes require additional exterior basement wall waterproofing or dampproofing, and not rely on only an interior treatment, such as crystalline waterproofing, paints or sealants.

Not Applicable

Crystalline waterproofing is available as a dry powder, mixed with water to form a slurry, sprayed or brushed onto porous concrete surfaces or applied to newly poured concrete, and worked into the surface. Surfaces must be sound, clean, and free of any other materials that may impair its bond to concrete. The sealant reacts with the concrete and cures over a two- to three-day period. The coating must remain moist during the process to assure that there is sufficient water available to complete the catalytic reaction. Periodically wetting the surface with a water mist sprayer, covering with wet burlap can complete the reaction. In contrast to other waterproofing materials, crystalline waterproofing applied to the exterior surface prior to concrete curing can reduce construction cycle time, and allow quicker backfilling.

It should be noted that crystalline waterproofing products can be applied to either side of a wall. Crystalline product's effectiveness decreases when applied to older concrete. The newer the concrete, the higher effectiveness of the product.

To facilitate curing, application should occur at temperatures above 40 to 45 degrees F and with protection from rain. Some applications may require two coats. On smooth concrete surfaces, sandblasting or roughening of the surface may be required prior to application of the product.

It is always recommended that crystalline products be applied to a properly prepped surface. Crystalline products cannot use acrylic bonding agents as the acrylic can inhibit the crystalline growth. Consequently, the materials are reliant on a mechanical bond. It is recommended that home owners have a qualified contractor apply the crystalline products.

Not Applicable

Crystalline waterproofing is known for its strength and effectiveness as waterproofing for reservoirs, sewage and water treatment tanks, and tunnels. Crystalline waterproofing can withstand salt spray and some chemicals.

It allows concrete to "breathe," so that moisture does not build up.

Disclaimer: The information on the system, product or material presented herein is provided for informational purposes only. The technical descriptions, details, requirements, and limitations expressed do not constitute an endorsement, approval, or acceptance of the subject matter by the NAHB Research Center. There are no warranties, either expressed or implied, regarding the accuracy or completeness of this information. Full reproduction, without modification, is permissible.