Cement boards complying with ASTM C1325, Specification for Non-Asbestos Fiber-Mat Reinforced Cementitious Backer Units are a suitable substrate for interior and exterior applications. ICC-ES Acceptance Criteria AC 51 for Precast Stone Veneer has been modified to include ASTM C 1325. ICC ES AC 59 on Direct Applied Exterior Finish Systems also allows cementitious backer units complying with C 1325. Cement boards have successfully been used in exterior applications for years and have demonstrated that they are a suitable alternative to metal lath and scratch coat.
Keywordsadhered; backing; cemetitious; masonry; mortar; unit; veneer;