Deck Mud is a mixture of washed and graded plaster sand meeting ASTM C 144 Specification and Portland Cement Type I-II-V that conforms to ASTM C 150. Deck Mud has been factory blended and designed specifically for use by the tile setting contractor. When the product is pre-blended it allows the cement to thoroughly coat the sand particles thus producing a stronger mix than job-site mixing in a dry pack application. The standard mix design is a 4:1 blend.