Zip, Zap, Zing! Instant, Custom Metal. GreenTech Roofing has advanced machining methods for manipulating metal products. From water jets to CNC bending machines, our ability to cut thick gauge stainless steel and aluminum products exceeds what other companies can only dream of. While building for a sustainable future, we manufacture most of our products from materials designed to last “life of building”. With other companies building products from galvanized steel and pop rivets, our products have welded corners and are made from aluminum, stainless steel, copper and zinc.