There are numerous products available for use as floor fills, patches, self-leveling underlayments, and trowelable underlayments. They include proprietary blends of compounds such as portland cement, calcium aluminates, and gypsum-based products. These are recommended by their manufacturers for smoothing rough or uneven subfloors, enhancing acoustical and fire characteristics of structures or as substrates to receive resilient floor covering for otherwise unsuitable subfloor conditions. When using these products, be sure to follow the manufacturer’s recommendations regarding application, drying time, and moisture testing.
Do not install Armstrong floors over gypsum-based products which have been applied to on- or below-grade concrete or damp, suspended concrete. For commercial and institutional environments, the floor fill, topping, or underlayment must have a minimum compressive strength of 3,500 psi. Armstrong’s S-194 Patch, Underlayment and Embossing Leveler , S-463 Level Strong and S-466 Patch Strong meet or exceed this requirement.
All recommendations and guarantees regarding their suitability as substrates for resilient flooring must be the responsibility of the manufacturer and installer of the substrate.