Sto's Gold Fill® is a ready-mixed, flexible, trowel-applied air barrier for use over prepared vertical above-grade concrete, concrete masonry, brick masonry, wood sheathing, glass mat gypsum sheathing, and cementitious sheathing substrates, as part of a StoGuard® air and water-resistive barrier system. It is used with StoGuard Mesh® to seal joints and seams and to protect rough openings in Sto proprietary wall systems and beneath multiple cladding types.