Enviroseal Concentrate is an effective water repellent liquid based on a solvent free silicone/siloxane emulsion for use above ground on porous brickwork, cement renderings, asbestos, cement/mineral boards, unglazed tiles, cast concrete, roughcast, stonework (including calcareous materials, i.e. those containing limestone), wood, canvas and leather. Surfaces treated with Enviroseal Concentrate remain permeable to vapour so that moisture within the structure does not remain trapped. Enviroseal Concentrate is clear and colourless and will not normally alter the appearance of treated surfaces. In some circumstances, however, very slight darkening may occur.