Plascon TradePro Solvent-Based Primer is an alkali-resistant primer for interior and exterior masonry surfaces. For use on substrates such as interior and exterior cement plaster, concrete and fibre-cement to protect subsequent coats, such as alkyd paints, against saponification. As a binding and sealing coat on soft and brittle cement plaster, porous paper-faced board, brickwork, soft board and gypsum plaster.