Bostik 50 lb. White PM Multi-Purpose Polymer-Modified Thin Set Mortar, $25.99 USD/Box, LL Flooring (Lumber Liquidators)

Bostik's polymer-modified thin set mortar is suitable for various tiles like ceramic, porcelain, granite, and more, applied inside or outside. It adheres to concrete, sound plywood (indoor and dry areas only), cementitious backer board, and well-bonded vinyl or ceramic tiles. Its advantages include suitability for both vertical and horizontal surfaces, quick setting, low absorption, and easy clean-up.