Toupret Humi-Block is a waterproof treatment powder filler for damp masonry that stops dampness and prevents humidity, either permanent or occasional, visible on raw masonry substrates. Levels uneven surfaces and can be used to fill up to 1cm per coat. For interior or exterior application, Humi-block adheres exceptionally on either dry, damp or wet substrates, but not dripping nor running. After completely drying, overcoats with any type of water borne coating or preparatory fillers. Powdered filler that requires mixing.