What is Oil Canning?
According to the Metal Construction Association, "Oil canning can be defined as visible waviness in the flat areas of metal roofing and wall panels. In technical terms, oil canning is referred to as elastic buckling (more commonly known as “stress wrinkling")."
Oil canning is a common occurrence in cold-rolled, light-gauge flat metal products, so if you see panels with noticeable waves between the seams, you’re most likely looking at oil canning.
Luckily, in most cases, oil canning is simply a cosmetic issue that doesn't diminish the integrity of a roof or wall system.
However, most people consider it unsightly and try to avoid it if possible.