Create the ultimate launching pad for your project, with the right preparation. British Paints All In One Acrylic Sealer Primer Undercoat is a multi-purpose interior and exterior preparation coat that gives protection to new or unpainted timber, weatherboards, hardboards, plasterboard, MDF, brick, cement/concrete* as well as galvanised iron. It has excellent hiding and filling properties and dries to an even, flat finish. Ideal under an appropriate British Paints topcoat.