Acid rain is crazy aggressive. It goes through cheap roofing sheets in three years, good galvanized sheets in 7 years, the best you can buy, triple-coated, in 10 years. Quarter inch steel railings rust through, even with frequent painting in about 7 years. It is hard on concrete, play equipment and about everything else. It come’s courtesy of Chinese coal fired electric generation, with yellow tinted clouds of sulfur laden solution being mixed with rain. All we can do is repair constantly and seek to go to higher grade materials like stainless steel, and ceramic coated concrete roof tiles. It is more expensive, but it lasts! We went through two homes this month and gave them at least another five years! At the same time we did the repairs new water filtration equipment was added. Thanks for your help!