Most manufacturers have their warranty's that are a minimum of 20 years. Most people confuse this as meaning the roof should never leak. That is not correct. The manufacturer's warranty is for defects in the materials. The workmanship warranty from the contractor is just as important. This means that the contractor has installed everything per the manufacturer's specifications and to code. Most contractors give 1-5 years Workmanship warranty. Here at All Phase Construction USA, we give a 10-year workmanship warranty.