Prefabricated modified composite polymer-bitumen waterproofing membrane composed of distilled bitumen and differentiated waterproofing masses, specifically designed for use over old bituminous waterproofing membranes self-protected with mineral slate. The upper face compound is composed of distilled bitumen and elasto-plastomers while the lower face compound is composed of distilled bitumen and special polymers which provide particular characteristics of adhesion and workability. A special waterproofing mass is used to bond the upper and lower compounds. MAXITEC RE-ROOFING is reinforced with a woven non woven single strand composite polyester fabric, with very good mechanical characteristics and exceptional dimensional stability. The membrane is self-protected with mineral slates which reduce heat absorption and improve the durability of the membrane. MAXITEC RE-ROOFING PA has a 10 cm side selvedge and a 15 cm head selvedge which promotes the adhesion between the various sheets.