Designed to flow easily and cover evenly, self-leveling floor underlayments are a practical, economical way to smooth and level concrete or plywood subfloors, making them ready for the application of floor coverings. The underlayments are poured or pumped onto the subfloor and are self-smoothing so no troweling is needed. Most of the products simply require spreading with a screed, float or other tool.
Self-leveling floor underlayments are based on a formula using portland cement, calcined gypsum or a combination of the two. This article focuses on the installation and performance of full-thickness underlayments formulated from calcined gypsum or gypsum/portland cement combinations.