Oil canning-the visible waviness that can turn a sharp looking building into an undulating mess. Also known as elastic buckling or stress wrinkling, oil canning doesn’t discriminate. It occurs in all metal panels: steel, zinc, copper, and aluminum.
Oil canning is caused by a lot of factors, like manufacturing. The complex manufacturing process that creates Insulated Metal Panels (IMP’s) includes many phases that take place on a continuous production line. On this long line, a few things can cause oil canning: the roll former, the heating of the skins for foam injection, and/or the cooling of the skins directly after foam injection.
So considering both nature and man are trying to turn your perfectly good metal into wavy gravy, a good building comes armed with a solution to the problem. The best and simple solution to controlling oil canning; use embossed steel.
It is standard in the IMP Industry to use embossed metal skins for a few reasons.
First, all roll formed coils have some level of oil canning from the mills. Single skin panels control this by keeping the panels narrow and adding ribs. With IMP, panel widths can be double that of single skin. The most common widths for insulated panels are 42” and 36”.
Second, the physics of how panels react to thermal stress, building movement, and even installation may induce oil canning. IMP reacts to thermal stress differently than single skin. Unlike single skin, the panel does not expand or contract. It bows outward. Depending on the attachment spacing, framing design, and orientation of the panel, this may introduce oil canning. And in regard to building movement, keep in mind ALL buildings move from wind and live loads. This normal deflection of the building will be felt in the framing—where the IMP is attached. If you add in framing alignment tolerances, over driven fasteners, and even handling—all of these factors may induce oil canning. Overall, remember science is sometimes working against you. So instead of trying to beat it—join it. Use embossed skins, because they embrace change.
Third, embossed skins diffuse light, making it difficult to see oil canning. Broad, flat surfaces don’t. They act like mirrors and make it easy to see every flaw. Embossing, on the other hand, acts like good make-up for a building. It hides the shortcomings. A very good example of this is why sheet rock in your home is textured. The texture diffuses the light, making it difficult to see imperfections in the dry wall.
So what do all these things prove? They prove a clear victor. Don’t be thrown when faced with a decision between embossed or unembossed IMP’s. There is no dispute. Embossed skins win.