Choosing metal roofing for your home is one of the smartest long-term investments you can make. Between its outstanding durability, energy efficiency, and modern style, it’s no wonder more homeowners across Canada are opting for metal over traditional asphalt shingles. However, during your research, you might come across the term “oil canning”, which can spark some worry. This refers to a visual phenomenon that sometimes appears in metal panels. It causes a wavy, uneven look across otherwise flat surfaces.
The good news? While oil canning is something to be aware of, it’s often misunderstood and rarely a reason to second-guess your roofing decision. Let’s take a closer look at what oil canning really is, why it happens, and why it shouldn’t scare you away from the many advantages of a metal roof.
What Is Oil Canning?
Oil canning is a term used in the roofing and cladding industries to describe visible waviness or slight buckling in flat areas of metal panels. It’s most commonly noticed on standing seam metal roofs and flat wall panels, particularly when sunlight hits at certain angles. This waviness does not mean the metal is damaged or weakened. It’s simply a visual distortion that affects the appearance more than anything else.
From a construction perspective, oil canning is recognized as an inherent characteristic of flat sheet metal surfaces. It’s nearly impossible to eliminate entirely in very flat panels, though some design and material choices can minimize its visibility. It’s important to remember that oil canning is a normal phenomenon and, in most cases, purely cosmetic, not a sign of structural problems.
Common Causes of Oil Canning
Several factors can contribute to oil canning, often starting even before the metal panels arrive at your property. One of the primary causes is thermal expansion and contraction. Metal naturally expands in the heat and contracts in cooler temperatures, and if the material doesn’t have enough room to move, slight buckling can appear. Over time, these natural shifts can become visible even on perfectly installed panels.
Other causes include installation methods, panel design, and material thickness. Panels that are too wide or made from thinner metal gauges are more prone to showing imperfections. Improper fastening techniques, uneven substrate surfaces, and stresses from manufacturing or forming the panels can also make oil canning more noticeable. Understanding these factors upfront helps set realistic expectations—and guides better material choices if minimizing oil canning is a priority.
Is Oil Canning a Structural Problem?
One of the most common concerns homeowners have when they notice oil canning is whether it indicates a flaw in the roof’s integrity. Fortunately, oil canning is almost always a cosmetic issue. It does not compromise the strength, waterproofing ability, or longevity of your metal roof in any way. A metal roof displaying minor waviness still performs just as effectively against rain, snow, wind, and hail as one without.
In fact, despite this, metal roofing still outlasts traditional roofing materials by decades. It resists fire, withstands severe weather, and offers superior energy efficiency compared to asphalt shingles or wood shakes. So while the slight visual imperfections of oil canning might take a little getting used to, they should not cause any doubt about the resilience and performance of your roof.
When You Might Want to Address It
While oil canning is cosmetic, there are certain situations where it might be more bothersome. Homes with large, highly visible roof areas—particularly those facing the street—might showcase oil canning more prominently. If you have a sleek, modern architectural design where crisp lines and perfect surfaces are essential to the aesthetic, noticeable waviness could feel more intrusive.
If oil canning becomes excessive—meaning deep or widespread buckling that goes beyond minor cosmetic ripples—it may be worth consulting your installer. In rare cases, severe oil canning could be the result of improper panel fastening or poor substrate preparation. A reputable roofing contractor should assess whether corrective action is necessary or if it’s simply a natural characteristic of the material and installation method chosen.
How to Minimize Oil Canning
Thankfully, there are several strategies to minimize the appearance of oil canning right from the start. First and foremost, selecting a thicker gauge metal can make a big difference. Thicker panels are more rigid and better at resisting the slight flexing that leads to visible waves. Additionally, opting for narrower panel widths reduces the amount of metal exposed across large surfaces, making waviness less pronounced.
Choosing textured or embossed finishes can also help. These surface treatments break up reflections and make any minor imperfections far less noticeable. Perhaps most importantly, careful attention to installation techniques—like proper fastening, substrate preparation, and allowing for thermal movement—can dramatically lower the risk of oil canning. And if you’re worried about it altogether, remember: oil canning can be avoided with other roofing profiles like corrugated panels or ribbed designs, which naturally mask any visual inconsistencies.
Should Oil Canning Affect Your Decision to Choose Metal Roofing?
In short, no—oil canning should not steer you away from choosing metal roofing for your home. The advantages far outweigh any potential minor visual concerns. A metal roof offers an unmatched combination of durability, beauty, and energy savings. It stands up to Canada’s harshest weather conditions and can easily last 40 years or more with minimal maintenance, offering excellent long-term value.
It’s essential, however, to set realistic expectations and work with a experienced installers. These experts understand how to minimize oil canning through smart material selection and best practices. When approached thoughtfully, a metal roof not only enhances your home’s protection but also adds architectural interest and a sleek, modern style that can boost your property value significantly.
Don’t Sweat the Small Waves—Enjoy the Big Benefits
At the end of the day, oil canning is a minor cosmetic issue in the grand scheme of what metal roofing has to offer. Those slight ripples don’t detract from the decades of strength, beauty, and efficiency your roof will provide. By choosing the right materials, working with an expert installer, and recognizing that some natural movement is part of metal’s character, you’ll be setting yourself up for long-term success.
Remember, despite this, metal roofing still outlasts traditional roofing by a wide margin. And if a perfectly smooth look is your top priority, oil canning can be avoided with other roofing profiles better suited to your aesthetic goals. Either way, you’ll enjoy a beautiful, reliable roof that delivers performance—and peace of mind—year after year.
