Are you considering or already have a metal roof? Do you keep hearing about or seeing examples of something called oil canning?
Most homeowners don’t think about oil canning until they see it on their metal roof. Some may even regret their decision and would’ve chosen another roofing material if they knew about it from the beginning.
I don’t want this to happen to you. No matter if you already have or are now considering metal roofing, oil canning is something you need to consider.
For over 30 years, Bill Ragan Roofing has provided homeowners with the transparent information they need to feel confident when choosing a roofing material. Because oil canning can affect your decision, let’s break down what you need to know about it.
By the end of this article, you’ll have the answers to:
- What is oil canning on a metal roof?
- Can oil canning happen to both metal roof types?
- Does oil canning affect a metal roof’s function?
- How do you prevent a metal roof from oil canning?
What is oil canning on a metal roof?
Oil canning is the “bubbling” look that can appear on flat areas of metal roofing panels. This creates a visible waviness or distorted appearance when seeing the roof from certain angles or in different lighting.
Oil canning is mainly caused by installers fastening the metal panels too tightly together. This gives them no room to expand sideways, which puts pressure on the metal as it goes through thermal expansion.
The built-up pressure eventually creates waviness when the metal isn’t able to contract back to its original form. Just know oil canning is possible with all the popular metal roofing materials, such as steel, copper, aluminum, etc.
Can oil canning happen to both metal roof types?
Oil canning doesn’t happen to both metal roof systems. A screw-down metal roof has too many ribs for it to oil can, but it’s very common in standing seam roofs.
Standing seam metal panels are fastened under each rib so the panels can expand and contract freely. But as I said, this isn’t fully possible if they’re fastened too tightly together, leading to oil canning.
While the amount of ribs prevents oil canning on a screw-down metal roof, so do the fasteners. The panels are fastened down directly to the roof deck with screws and washers, which means the metal can’t expand and contract fully.
This does wallow out the washers, but it also means there’s no opportunity to oil can due to the large number of fasteners and lack of open surface area on the panels.
Does oil canning affect a metal roof’s function?
Oil canning does cause an aesthetic issue that some homeowners don’t like, but it doesn’t cause any functionality problems. So, you don’t have to worry about roof leaks or a shortened lifespan if you see oil canning.
That’s why almost all metal roofing warranties don’t cover oil canning. Simply put, there just isn’t anything that would cause the metal roof to fail because the panels are a little wavy.
However, you must consider oil canning if curb appeal and aesthetics are a big deal to you. The last thing you want is to look at your metal roof with regrets for the next 30 to 50 years.
How do you prevent a metal roof from oil canning?
Unfortunately, there’s no 100% way to prevent oil canning. Metal panels will always try to revert to their original form after going through thermal expansion.
However, there are things you can do to minimize the chances of oil canning. The best way is to hire a roofing contractor with metal roof installation experience.
This will help ensure the metal roof is installed correctly and the panels aren’t fastened too tightly together. Another thing you can do is invest in a thicker gauge of metal that won’t expand and contract as much.
This will cost more but lessen the chance of oil canning. You can also choose a lighter color that won’t show the waviness as much as darker colors.
Which type of metal roof is right for you?
Now you know what oil canning is, if it affects the function of a metal roof, and if you can prevent it completely. As I said, there’s no 100% guarantee that metal panels won’t show signs of oil canning.
However, hiring a roofing contractor with metal roofing experience is the best way to minimize the risk. And remember, it only happens to standing seam metal roof panels.
Oil canning is enough to turn homeowners towards a screw-down metal roof. But there are other differences between the two metal roof systems that matter much more.
So, before doing anything else, you need to know how both metal roofs compare on the things homeowners care the most about.
Check out Metal Roofs: Standing Seam vs. Screw Down to learn which one is right for you based on pricing, lifespan, curb appeal, and more.
