Oil canning is a waviness that often can appear in the flat sections of metal roofs. It can affect all types of metal roofing materials, including steel, copper, aluminum and zinc. This condition also is referred to as stress wrinkling or elastic buckling. Whatever you call it, oil canning can seem more prominent in bright sunshine and at different times of day.
Different stresses within the metal can be introduced during the manufacturing process and cause oil canning. When the metal tries to revert to its original form to lessen the pressure, it can buckle and produce the wavy appearance. Oil canning also can result from improper storage, incorrect fastener installation and misalignment of panels.
You can minimize oil canning in several ways. One option is purchasing a thicker metal, as the thickness will make it more difficult for the metal to move. You also can use a rib roller to break up the flat spaces on the panels. Another strategy includes ensuring the roof deck is even before installation because an uneven deck invites more metal buckling. Additionally, you can try using narrow-width panels and choosing a low-gloss or matte surface, which reduces reflection.
Although some customers may complain about oil canning, it is only a cosmetic issue because it does not affect the structural viability of the roof system. However, if you are installing a metal roof system, protect yourself by including an oil canning disclaimer.
Metal roofing and especially lengthy flat span sheet metal panels will often exhibit waviness, commonly referred to as “oil canning.” Oil canning pertains to aesthetics and not the performance of the panels and is not controlled by the Contractor. Contractor disclaims liability for oil canning and any aesthetics-issues related to oil canning. Oil canning shall not be grounds to withhold payment or otherwise reject the workmanship of Contractor.
Disclaimer: The information contained in this article is for general educational information only. This information does not constitute legal advice, is not intended to constitute legal advice, nor should it be relied upon as legal advice for your specific factual pattern or situation.