The No-Leak chimney flashing systems use industry-recommended, 26-gauge steel and 16-ounce copper. The design of the system allows for conventional installation, following industry standard guidelines, to stop chimney leaks due to chimney flashing. The systems are not a temporary fix; they prevent the most common cause of roof leaks, period. (Note: No-leak chimney flashing systems do not use aluminum because of the corrosive reaction between mortar and concrete in contact with aluminum. The reaction rate increases when moisture is present.)