Guide to Oil Canning in Metal Roofs: Causes and How to Minimize It

March 28, 2024

Adding a metal roof to your house in Louisville, KY, is a significant investment, which is why you should know about oil canning, an inevitable effect for metal roofs. Read on as our metal roof contractors walk you through what oil canning is and what we do to minimize it.

What Is Oil Canning in Metal Roofs?

Oil canning in metal roofs refers to the noticeable waviness or distortion seen in flat metal panels, particularly in expansive areas. This effect is an inherent trait of light-gauge, cold-rolled metal products, regardless of the material used, including steel, galvanized steel, stainless steel, copper, zinc, and aluminum. 

Essentially, oil canning is a visual phenomenon that can detract from the smooth appearance of a metal roof. The waviness associated with oil canning in metal roofs can vary significantly depending on factors such as color, finish, lighting conditions, and viewing angle. 

Does Oil Canning Affect Metal Roofs’ Structural Integrity?

Despite its visual impact, oil canning does not compromise the structural integrity of the metal panel system. Warranties do not typically cover this cosmetic issue for weathertightness, substrate, or paint, as it does not pose a risk of roof failure. Fortunately, oil canning has identifiable causes, and multiple strategies to mitigate them.

Oil Canning Due to Stresses during the Production of Metal Panels

Oil canning in metal panels can be attributed to stresses that metal panels encounter during various stages of the production process. Early in the flattening and coiling production, three distinct stresses may contribute to oil canning. 

  • Full center stress occurs when the middle section of the sheet or coil is longer, resulting in ripples or buckles along the center. 
  • Wavy edge stress arises when the edge of the sheet or coil is longer than the middle. 
  • Camber stress is the deviation from a straight line when the coil or sheet is laid flat. 

Additionally, during rollforming and slitting, the inherent memory of metals causes them to attempt to revert to their original form, leading to movement and warping that can exacerbate oil canning. 

How Our Metal Roof Contractors in Louisville, KY, Install Metal Panels to Minimize Oil Canning

At Pro City Roofing LLC in Louisville, KY, we take great pride in delivering high-quality metal roofing installations that not only look impeccable but also stand the test of time. Over the years, we’ve honed our techniques to minimize oil canning in metal roofs. Here’s how we do it:

Ensuring Proper Usage, Handling, and Storage

From the moment metal coils and sheets arrive at the job site, we prioritize proper handling and storage. We know that even the slightest mishandling can increase the risk of oil canning down the line. That’s why we always carry panels perpendicular to the ground and provide support every 10 to 12 feet, as recommended by manufacturers. Our metal roof contractors in Louisville, KY, treat metal panels with the utmost care to minimize any potential damage.

Careful Alignment of Panels

Misalignment is a recipe for disaster when it comes to metal roofing. We understand that precise measurement and installation are paramount to prevent stresses that can lead to oil canning. Whether it’s ensuring that panels are aligned from ridge to eave or maintaining consistent spacing between them, our metal roof contractors pay close attention to every detail to achieve perfect alignment.

Leaving Adequate Space for Thermal Movement

Thermal expansion and contraction are natural phenomena that metal panels must accommodate to avoid oil canning. We’re mindful not to restrict this movement, especially at the edges. By allowing the panels to expand and contract freely, we minimize the stress on the metal and reduce the risk of oil canning.

Installing Panels on a Leveled, Consistent Roof Deck

A level roof deck is the foundation of a successful metal roofing installation. Whether the deck is made of metal, plywood, or OSB, we take the time to ensure it’s perfectly level before laying down any metal panels. This attention to detail pays off in the long run, as it prevents unnecessary stress on the metal and helps maintain a smooth, flawless appearance.

How Your Metal Roof Choices Can Minimize Oil Canning

There are steps you, as a homeowner, can take to minimize oil canning as well! Here’s how:

Opt for Lighter Colors and Low-Gloss Finishes

We recommend that you choose lighter colors and low-gloss finishes for your metal roof in Louisville, KY. Lighter colors tend to reflect more sunlight, reducing the amount of heat absorbed by your roof. This can help minimize the expansion and contraction of metal panels due to temperature fluctuations, thereby reducing the risk of oil canning. Additionally, low-gloss finishes can help hide minor imperfections in the metal surface, making any potential oil canning less noticeable.

Choose Metal Panels with Rib Rollers

Another effective way to minimize oil canning is to opt for metal panels that have rib rollers. These rollers create ribs or striations in the metal surface, which help to stiffen the panels and reduce the likelihood of waviness or buckling. The ribs also provide additional support for the panels, helping to distribute any stresses more evenly and minimizing the risk of oil canning.

If you are still in the process of choosing the roof type for your home, take a look at the top four reasons to opt for a metal roof in Louisville, KY. Our metal roof contractors at Pro City Roofing LLC are ready to install your new metal roof. Contact us today!