Bostik 1 Gallon 425 Multi-Purpose Acrylic Latex Admixture, $25.99 USD/Box, LL Flooring (Lumber Liquidators)

The Bostik 425 Acrylic Latex Additive is a high solids acrylic emulsion that enhances the performance of various Bostik products including Ceramic Tile Grout and Tile-Mate Thin Set Mortars. It helps control the curing of cement mortars and grouts, offering improved adhesion with thin set mortars. This admixture also enhances water resistance in grouts and mud beds, and improves flexural and compressive strengths. It's useful for reducing grout cracking in wood structures and preparing bond coats.