Sto EmeraldCoat® is a ready-mixed, flexible waterproof air barrier membrane. It is applied directly to wall sheathing and functions as a vertical above grade waterproof air barrier when combined with StoGuard® joint and rough opening treatment. Sto EmeraldCoat® is one component of the StoGuard Assembly, which is a fluid applied membrane that offers a superior waterproof air barrier. StoGuard can be used beneath various claddings including Portland cement stucco, vinyl, cement board siding and brick.