Sikagard 277: Water-Repellent Sealer (Formerly MasterProtect H177)

Sikagard 277: Water-Repellent Sealer

Sikagard 277 is a high-performance, water-based, VOC-compliant, clear silane/siloxane sealer designed for dense, vertical masonry surfaces like hard-burnt brick. Questions? Contact Us.

Sikagard-277 Enviroseal is a high-performance, water-based penetrating sealer made to protect dense vertical masonry from moisture. Formerly known as MasterProtect H 177, it uses a silane/siloxane formula that penetrates into the surface instead of leaving a coating or film on top. It is designed for vertical brick, stucco, and aged limestone on both interior and exterior above-grade applications.

Once applied, Sikagard-277 Enviroseal helps repel rain and reduce moisture intrusion through brick and mortar. At the same time, the treated surface remains breathable, allowing moisture vapor from inside the wall to escape. The sealer dries clear and is non-staining, so it protects the masonry without noticeably changing its color or appearance. It also provides a strong water-beading effect during rainfall.

The penetrating formula reaches approximately 1/16 to 3/8 inch into the substrate, depending on the material. Testing on brick walls showed more than a 94.8% reduction in water leakage, while artificial weathering testing showed no change after 1,500 hours of exposure. This makes it a good choice for masonry where long-term water resistance is needed without sealing moisture inside the wall.

Sikagard-277 Enviroseal is applied with a low-pressure, non-atomizing sprayer and is flooded onto the surface from the bottom up to help get maximum penetration. Coverage is typically 100–175 sq. ft. per gallon on brick and 80–140 sq. ft. per gallon on stucco, depending on surface porosity. Extremely porous surfaces may require a second coat.

The product is milky white when wet but dries clear, has a typical drying time of about four hours under normal conditions, and cleans up with hot soapy water before it dries. It is a practical option for protecting masonry while keeping the original look and allowing the wall to breathe.