DURO MASTIC™ AC is a waterproof and UV resistant liquid membrane used either for long-term waterproofing or as a decorative coating.It cures to form a flexible waterproof membrane or coating by varying the thickness and number of coats. It is resistant to weathering, fungi and algae. Although the membrane is waterproof it allows the substrate to breathe, reducing the risk of blistering. DURO MASTIC™ AC has been used for over 20 years as a roof membrane and protective coating.