Building Stone Mortar Words: Dan Kamys www.specmix.com Whether the specification calls for soft or hard stone, SPEC MIX stone mortar mixes are engineered to match the specific properties of each stone to increase the mortar-to-stone bond strength while allowing the mason to lay more stone every day. Meets ASTM C270 requirements. Mortar type should correlate with the particular masonry unit to be used. SPEC MIX Building Stone Mortar is available in formulations for hard stones such as granite and soft stone such as limestone. The specifier should evaluate the density of the stone masonry unit specified to ensure that the appropriate mortar is selected to match to the hardness of the stone masonry units for the project. Each product is 100% dry, preblended in 80 lb. or 3,000 bags, eliminating the need to measure and add liquid admixtures on site, which in turn ensures quality control while increasing jobsite productivity.