Flashing has to be installed over areas of the roof where shingles alone will not provide protection against water seepage. Chimney flashing is one of the most important details of a successful residential roof system. The best and most effective way to protect your roof is through using a flashing.
Tin coated steel and galvanized steel will eventually rust and corrode. The most common color for flashing is a silver-grey, which comes from aluminum or galvanized steel. Aluminum and galvanized steel are less expensive, but still effective choices. Aluminum is considered 50-year compatible, is much less costly and non-toxic, but is still not as easy to field fabricate as galvanized steel, copper and lead. Daman Pearse from Cincinnati Roofing Contractors has been using copper for many years and believes it has its place in repairing certain types of roof. A lot of residential roofs in the Cincinnati area use copper flashing. Prices for metals like aluminum, lead, and copper can go much higher. Steel can be recycled, and levels of scrapped steel are far lower than copper.
Metal roof flashing is critical for standing seam roof applications because the metal roof is not attached using screws along the panels. Copper roofing panels are available in traditional double-lock standing seam, flat seam and ornamental diamond panels. The vertical lip to the left will be locked into the standing seam copper roof to be installed along the entire porch roof. You can use a board laid flat on the roofing to get a better idea of the real slope of the roof, as shingles can be lumpy. The apron is cleated at its upper edge and is joined to the copper roof pans with a transverse seam. You may have to nail the lower edge to the roof to hold it flat.
Derek Pearse writes more about Copper Flashing on his website www.cincyroofing.com