What is Oil Canning? Ways to Prevent Aesthetic Defects in Metal Roofing Panels

By AEP Span. 

If you are used to working with metal roofing and siding, then you know oil canning is a prevalent issue.  

Oil canning is a phenomenon that refers to the slight buckling or deformation found in sheet metal, usually seen on flat surfaces. It manifests as wavy or rippled lines that can affect the overall look of a building. However, oil canning is not just an undesirable visual problem, it's a natural feature of all cold-rolled flat metal and so it should not lead to rejection. Many may find the appearance displeasing, but it's important to recognize that it does not compromise the metal's structural strength or its waterproofing capabilities. Let’s investigate the underlying causes of oil canning and discuss potential remedies. 

What is oil canning? 

Oil canning, also known as stress wrinkling or elastic buckling, refers to the visible waviness or rippling that can occur in metal panels. It is more noticeable on flat or smooth surfaces and can be quite frustrating for those seeking a seamless and blemish-free appearance. 

Jeff Haddock, AEP Span Technical services manager, mentions “Oil canning is caused by internal stresses within thin-gauge metals. These stresses can be introduced during the production of the coil and fabrication of the panels. Field installation techniques, conditions and construction tolerances can also greatly impact the presence of oil canning.”  

Visible rippling on the flat surface of the metal siding panel 

Common causes: 

1. Thermal Expansion and Contraction: Metal expands and contracts with temperature changes, and if the panel is not properly installed or restrained, it can lead to stress in the panel and result in oil canning. 
2. Manufacturing Imperfections: Variations in the manufacturing process, such as uneven tension in the metal or variations in the thickness, can contribute to the issues. 
3. Improper Handling and Storage: Mishandling the metal panels during transportation, storage or installation can cause distortion or dents, leading to unsightly appearances. 
4. Insufficient Substrate Support: Inadequate structural support and spacing between the framing members can cause the metal panels to flex, leading to a rippling effect. 

Solutions to oil canning: 

1. Proper Installation: Following the manufacturer’s guidelines for installation is crucial to minimize the risk of an unsightly appearance. Proper fastening, spacing and support are essential to ensure the panels are installed correctly. 
2. Panel Selection: Choosing metal panels with thicker gauges or choosing a panel with striations or ribs can help reduce wavy or rippling appearances. 
3. Adequate Substrate Support: Ensuring the framing members are properly spaced and structurally sound to help minimize flexing. 
4. Regular Maintenance: Conducting routine maintenance, such as cleaning debris and inspecting for any signs of damage, can help prevent any issues from worsening. 

Remember, oil canning may not always be completely avoidable, especially in certain weather conditions or with extensive panel spans. However, by understanding the causes and implementing appropriate solutions, you can significantly reduce the occurrence and minimize the visible effects of oil canning on your metal roofing and siding project. 

For more information, check out this great article from Metal Construction News. For more information on our metal roofing and siding products that are designed to minimize the appearance of oil canning, check out our striated panel options or contact our team of experts who will be happy to assist you. 

Original source: AEP Span