Florida Certified Roofing Contractor CCC 1334537
What causes oil canning in standing seam metal roof panels?
A straight answer from a Florida certified roofing contractor — then what you can check yourself and when to call. Free quote: (954) 775-8990.
Oil canning, the wavy or rippled look in the flat part of a metal panel, comes from stress in the metal. That stress usually builds up in one of three places: the coil and roll-forming process, an uneven roof deck under the panels, or panels that cannot move freely as they heat and cool.
It is mostly a cosmetic issue. Wide flat panels, thin metal, dark colors and glossy finishes make it easier to see, and the angle of the sun changes how obvious it looks.
Why it happens
Metal is flattened and formed from coil before it reaches the roof. If the coil carries built-in tension, or the panel is rolled or handled roughly, the stress can show up as waves once the panel is installed. Wide flat pans with no stiffening ribs or striations are the most prone, because nothing breaks up the surface.
Deck preparation is the installation cause we see called out most in the trade, and it is on our list of metal roofing hazards. Standing seam panels sit directly on the underlayment and deck. Raised fastener heads, warped or uneven plywood, swollen seams between sheets, or a deck that was patched without being brought level can all telegraph through the panel as ripples. A smooth, flat, properly fastened deck matters as much as the panel itself.
Movement is the third cause. Florida roofs see strong sun, heat and cool-downs after afternoon storms. Standing seam panels are meant to float on clips so they can expand and contract. If clips are fastened too tightly, installed out of line, or panels are forced into place, the metal binds and buckles. Installing in very hot conditions, or pulling panels tight across a long run, can add to it.
What you can check yourself
Look from the ground at different times of day
Oil canning shows most in low, angled light, so look in morning and late afternoon. If the waves fade at midday, the panel is likely just reflecting light unevenly.
Note where the waves are
Ripples in the middle of flat pans point to panel stress or deck unevenness. Waves that follow a line, such as a deck joint or a rafter, suggest the substrate underneath.
Look at the deck from the attic
If you have safe attic access, use a flashlight to check the underside of the decking for sagging, stains, or uneven sheets. Stay on the framing or a proper walkway, and never go onto the roof.
Check ceilings for leak signs
Look for stains or soft spots near the wavy areas. Oil canning alone does not leak, so any staining points to a separate problem such as a flashing or fastener issue.
Find your paperwork
Check the panel specification and manufacturer warranty language. Some manufacturers address oil canning as a cosmetic matter, so it helps to know what yours says.
When to call a pro
Call us if the waves are severe, are spreading, or appear along with loose fasteners, gaps at flashings, or any sign of water inside. Those suggest the deck, clips or panel movement need attention, and that cannot be fixed from the ground. Oil canning that is only a cosmetic ripple does not need urgent action, but a professional can tell you which kind you have.
Roofing work in Florida legally requires a licensed roofing contractor and generally a permit from the local building department; a contractor's license is verified on the Florida DBPR website. Our Florida Certified Roofing Contractor license, CCC1334537, can be checked there. Call (954) 775-8990 or use the estimate form for a free estimate.
What a pro will do
- Inspect the panels and the deckWe look at where the waves fall, how the clips sit, and whether the deck underneath is flat and sound.
- Fix the deck first on a new installTear-off and deck replacement, including rotten plywood and fascia, is part of our written scope so panels go onto a flat, sound surface.
- Use the right underlayment and clipsHigh-temperature underlayment and concealed-fastener clips set to let the panels float reduce binding as the metal heats and cools.
- Check flashing and fastening detailsWe inspect flashing at skylights, vents and wall terminations and the hip, ridge and valley details, because wind-uplift areas and penetrations are where real problems tend to start.
- Put it in a written quoteOur flat-rate quote says what is included, and permits are pulled under our license, inspections scheduled and passed, and the permit closed out.
Related questions
- Does oil canning cause leaks or weaken the roof?
- Oil canning by itself is generally an appearance issue and does not make a roof leak. If you also see loose fasteners, open seams or stains inside, those are separate problems worth having inspected.
- Can oil canning be fixed once it appears?
- Panels are hard to flatten once the waves have formed. Depending on the cause, the options are usually to accept the look, correct a binding clip or detail, or replace the affected panels. A look in person is the only way to say which applies.
- Do exposed-fastener metal panels oil can too?
- Yes. Any flat metal panel can show it. Exposed-fastener panels often have ribs that break up the surface, which helps hide it, but an uneven deck or overdriven screws can still cause waviness.
- Does Florida heat make oil canning worse?
- Heat adds thermal movement, so panels that cannot slide on their clips are more likely to buckle. Dark colors absorb more heat and also make waves easier to see.
- Do the building code rules differ depending on where I live?
- Florida Building Code requirements for panel attachment, uplift and underlayment apply statewide. Broward and Miami-Dade are the High-Velocity Hurricane Zone, with stricter rules and Miami-Dade product approvals (NOA). Elsewhere, products need Florida Product Approval or local approval. Confirm details with your local building department.
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