What is oil canning in roofing?

Oil canning refers specifically to a distortion or waviness that can appear in flat metal roofing materials, particularly in panels that are large or thin. This surface defect occurs as a result of the natural behavior of metal when subjected to temperature fluctuations, mechanical stress, or incorrect installation techniques. It is called "oil canning" because the bulging appearance is reminiscent of the shape of old oil cans.

Often, oil canning is not a sign of structural failure or can cause leaks but may impact the visual aesthetics of the roofing. Awareness of this phenomenon is essential in the selection and installation process of metal roofing to ensure proper design and maintenance, which can help minimize its occurrence. By understanding oil canning, roofing professionals can also choose appropriate materials and installation methods, potentially reducing the risk of this issue emerging in projects.