In this edition of Tech Talk, Eric demonstrates how to determine stretch factor on a metal roof. Stretch factor has to be taken into consideration when coating a metal roof because the surface area of the metal panels is larger than the size of the entire roof, due to the ribs of the metal panels. In figuring out the stretch factor, contractors will be able to accurately determine how much coating they need for metal roof projects. We also offer the Metal Roof Estimating Guide in our Support Documents for determining stretch factor.