2024-25_NTCA_Reference_Manual_dig_dwnld

Curing Compounds, Release Agents, and Sweeping Compounds

Form Release Agents and Sweeping Compounds

Correction

Curing Compounds

These suggested corrections and/or a combi nation of suggested corrections may provide improved conditions and a serviceable product.

Form release agents used in concrete construction and slab release agents used in lift slab construction often make the same claims as those made for concrete curing compounds. The same cautions apply for these materials as for concrete curing compounds. They are unacceptable for use where tile, stone and mortar beds are bonded directly to the surface. Obtain the full and complete labor and materials guarantee and understand any limitations or conditions for removal of form release agents imposed by the manufacturer before proceeding with the tile and stone installation. Sweeping compounds – oil based and wax based – are used during the duration of the construction process to keep dust down. The sweeping compounds close the pores in the concrete and self leveling substrates, acting as a bond breaker.

Curing compounds shall not be used where tile, stone, and mortar beds are bonded directly to the surface. These surfaces shall be wet/damp cured. Manufacturers claim some resinous concrete curing compounds and sealers have been formulated and designed to lay on the surface of the concrete, become brittle as they age, and flake off with traffic and time, leaving no residue. It is claimed that use of these types of resinous curing compounds will have no effect on the bonding of tile to that surface. Industry support organizations and the tile industry’s experience indicate otherwise, and these claims should not be accepted. There is a strong possibility that tile installed on these type surfaces will lose bond, produce a hollow sound, and result in cracked or broken tile or stone. Other types of “cure and seal” curing compounds based on fluosilicates that combine chemically with the free lime in Portland cement have been declared as not conforming with concrete curing requirements, and may also cause the same problems as the resinous materials. This type of material should not be used without a full and complete labor and materials guarantee from the curing compound manufacturer if these are and must remain in place.

Shot-Blasting A very effective method involving metallic abrasives thrown at high velocity by a rapidly rotating blast wheel. This system includes a built-in vacuum process that minimizes dust. Water Blasting High pressure water treatment – 9,000 to 10,000 psi. – should be done by experienced personnel. Lower pressure washing – 1,500 to 3,000 psi – may be suitable for removal of residue from self dissipating curing compounds. Grinding Grinding can leave the surface smooth, and etching may be necessary to assure a mechanical bond. Chemical Should be done only by experienced personnel using nonflammable materials that are water cleanable and wax free. When this procedure is used, careful retesting is necessary. Always rinse thoroughly, allow to dry, and retest. In addition to the above procedures, some of which are suitable for vertical surfaces, lath may be installed.

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NTCA Reference Manual | 2024 / 2025

Chapter 2 | Substrates