The Fascia Metal Blues: Oil Canning & How To Fix It
Written By Cody Profitt
what is oil canning?
Oil canning is a common phenomenon in metal roofing that creates visible waviness or rippling across the surface of metal panels. The term comes from the similarity to what happens when you press the bottom of an oil can—it pops in and out, creating a wavy, undulating appearance.
This aesthetic issue manifests as alternating high and low spots across the metal surface, creating a “wavy” or “rippled” appearance that can be particularly noticeable when light hits the roof at certain angles. While oil canning is primarily a cosmetic concern, understanding its causes and prevention methods is crucial for maintaining the professional appearance of your metal roof.
types of oil canning
Stress-Related Oil Canning
This occurs when panels are subjected to external forces during installation or from structural movement. It often appears as localized areas of waviness near fasteners or panel edges.
Thermal Oil Canning
Results from temperature-induced expansion and contraction cycles. This type typically affects entire panel lengths and is most noticeable during temperature extremes.
Coil-Set Oil Canning
Inherent waviness from the manufacturing process that becomes apparent after installation. This type is often consistent across multiple panels from the same coil of metal.
The Fascia Metal Blues: Oil Canning & How To Fix It
“That looks like shit,” Bill growled to me as we stood on the hill overlooking his newly installed fascia metal. It was 2015 and Bill had just paid some goofball roofer (me!) to install a fascia wrap as part of his roof package. The roof was a striated 24G standing seam panel, and I had used the exact same metal for the fascia wrap, yet as Bill said perfectly: “it looks like shit.”
“I agree sir, and I will figure out how to fix it,” I said, as I stared at the ugly, twisted, black metal that I was now responsible for. I knew that II had to do something to make it right, but I just couldn’t figure out WHY the fascia metal had distorted so much, I mean, we made it on a brake and it was straight before we installed it…what happened? I set out on a mission that day to understand oil canning and come up with the best set of practices to avoid it. I owed it to myself and my clients to not end up in this situation again.
If you’ve ever wanted fascia metal and ended up with wavy mess, you’ve encountered the dreaded “fascia metal blues.” Oil canning, as it’s known in the industry, can take a beautifully designed project and make it look unprofessional/cheap. At Comanche Roofing, we’ve seen it all, and I’ve developed systems and techniques to ensure our fascia metal installations are flawless every time. Let’s dive into why oil-canning happens first:
Why Does Fascia Metal Oil Can?
Oil-canning is the visible waviness or distortion in flat metal pieces. While it’s often a cosmetic issue, it can make even the most skillful installation look subpar. Here are the key reasons:
Thermal Expansion and Contraction:
- Metal naturally expands and contracts with temperature changes.
- Without the right installation methods, this movement creates stress, leading to buckling and rippling over time.
- Texas swings through temperature fluctuations.
Rigid Fastening Methods:
- Using fasteners that lock the metal in place restricts movement.
- When the metal tries to expand or contract, it has nowhere to go, causing deformation.
Substrate Irregularities
- Uneven or imperfect substrates put pressure on the metal, creating visual distortions where pressure is applied.
- Framing nails can protrude from fascia.
Material Thickness
Thinner metals, such as 26-gauge, lack the rigidity to resist buckling, making oil canning more likely.
High-Gloss Finishes
- Glossy finishes reflect light unevenly, highlighting even minor imperfections in the metal.
- The best install can show distortion based on reflectiveness of the metal
How Comanche Roofing Mitigates Oil Canning
At Comanche Roofing, we’ve developed a proven system to combat oil canning and ensure fascia metal installations look as professional as they should. Here’s how we do it:
1. Custom Clip System with Concealed Fasteners:
- Our custom clip system uses concealed fasteners to secure the fascia metal while allowing it to move freely with thermal expansion and contraction.
- This prevents the stress that leads to oil canning and eliminates the visual distraction of exposed fasteners.
2. Foam Strip Installation:
- We take the extra step of installing fascia metal on a strip of foam.
- This technique accommodates minor substrate imperfections and allows the metal to settle evenly: reducing pressure points that can cause distortion.
3. Low-Gloss Finishes:
Glossy finishes magnify any imperfections in the metal. That’s why we use ultra low-gloss finishes, which create a more subtle, matte look while masking any minor irregularities. The result? A clean, professional appearance every time.
4. Low Gauge Metals for Extra Rigidity:
- While thinner metals are more prone to warping, we opt for 22-gauge fascia metal.
- The added thickness provides the rigidity needed to resist oil canning, ensuring that your fascia metal stays smooth and stable.
- This in combination with our other practices ensures a consistent install.
5. Attention to Detail:
- A quality installation starts with a solid foundation.
- We meticulously prepare and install out fascia metal to give a smooth, even finish.
Whether it’s a residential project or a complex commercial installation, our team combines craftsmanship, premium materials, and industry expertise to eliminate the “fascia metal blues.”
Oil Canning FAQs
Is oil canning harmful to my roof?
Oil canning is mostly a cosmetic issue and does not affect the structural integrity or waterproofing of your metal roof. While it may impact the appearance, especially under certain lighting conditions, it won’t compromise the roof’s performance.
How can you prevent oil canning during installation?
To reduce the risk of oil canning, it’s important to:
Use thicker gauge metal panels
Install panels with proper alignment and spacing
Ensure a flat and smooth substrate
Avoid over-tightening fasteners
Choose panel designs with minor ribs or striations to mask waviness
Working with an experienced installer who understands these techniques is key to minimizing oil canning.
Say Goodbye to Oil Canning
If you’re tired of fascia metal that looks less than perfect, let Comanche Roofing show you how it’s done. Contact us today to learn more about our custom solutions and why we’re the trusted choice for high-quality fascia metal installations.
Let’s put an end to the fascia metal blues—because your project deserves nothing but the best.