Normally the painting of a polymer bitumen membrane is carried out directly on the exposed surface. This membrane must be an APP (plastomeric) membrane as SBS membranes cannot be left exposed to UV rays. The membranes also require mineral protection (slated membranes) or a heavy protection (cls or other cover). Where traditional membranes modified with APP are concerned these membranes must be painted with the correct substance (POLYVER ALU) which is compatible with the bitumous matrix of the product. Usually the paint has a highly reflective quality and often has an added aluminium pigment in order to maintain the membrane temperature as low as possible; therefore it is not advisable to use dark colours.