Waterproof sealant based on concentrated dispersion of modified rubber with special resins, glass fibers, and reinforcing agents. Upon drying, it forms a layer that adheres firmly to the substrate. It is impermeable and has the necessary elasticity (movement up to 1 cm), which allows for the dilatations to which materials used in construction are subject. The sealant adheres to any substrate. It is resistant to solar and UV radiation, is waterproof, and can be loaded. After drying, the sealant can be painted as desired.