Did you ever wonder how easily an empty oil can distorts under pressure from your thumb? This is a characteristic of all thin metal sheet of which kitchen foil is a prime example. The phenomenon may occur on some sheet metal roofs too. We discuss what oil canning is in this context, and how to prevent the distortion.

Oil Canning During the Product Cycle

The key to avoiding the defect is thickening the metal, and ribbing the surface during rolling. However, this increases the quantity of raw material and therefore the cost of the finished product.

Metal Dynamics During Production

Manufacturers of cheap roof sheeting may try their best to avoid the rippling, but the following stresses may still cause it.

1… A long sheet or coil can ripple or buckle down the center.

2… Whereas a broad sheet or coil may distort across the edge.

3… Laying a sheet over a curve distorts it causing rippling.

Moreover, Sheffield Metals confirms all metals have memories. Roll forming and splitting during production can artificially distort the material. Oil canning may follow as it warms and moves in an attempt to return to its original form.

Handing During Transportation

Handling metal sheets incorrectly can induce post-manufacture oil canning, if carried flat and allowed to bend. Therefore, raw metal sheets should be transported vertically, and supported every ten feet if they are not resting on a flat level surface.

Allowing the metal to twist, warp, bend etc. can result in temporary or permanent rippling. Unfortunately, many roofers do know this and blame the manufacturer. The poor home owner is swept up in a topic they do not understand!

Common Errors During Installation

Flat metal roof sheets need careful alignment before fastening down. This is the only way to prevent distortion that the material will fight as long as it is there. It should be laid flat without any humps, bumps and curves. And then fastened down securely without over-driving fasteners that must be correctly aligned.

The Right Installer for Flat Metal Roofs

It follows the material should be sufficiently thick, and ribbed to counter oil canning as we always recommend. The roofing company must know how to transport the material, lay it down properly and fasten it correctly.

Valiant Exteriors meets these requirements by employing skilled artisans, who understand how to lay the right roof sheets correctly. We’ll happily pop by and provide free advice if you share a few photos first. We provide a full-on service keeping water where it belongs, and your home looking good.

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Storm Damaged Metal Barn Roof Displaying Oil Canning (C.E. Price BY Public Domain)