Things You Can’t Unsee: How Not to Install a Standing Seam Metal Roof (And How to Know if Your Contractor Knows What They’re Doing)

Standing seam metal roofing has become one of the most sought-after premium roofing systems in the Bay Area — and for good reason. Unlike the more traditional asphalt shingles, a standing seam metal roof is built from long, continuous metal roofing panels that lock together with raised vertical seams. 

Those seams aren’t just for looks; they are engineered to shed water, withstand wind, and allow the roof to expand and contract with temperature changes. Homeowners choose standing seam metal roofs because they deliver unmatched durability, a clean, modern appearance, fire resistance, and a lifespan of over 50 years. Whether it’s made of aluminum, galvanized steel, or copper, standing seam metal roofing is the gold standard for anyone wanting a roof that not only looks amazing but lasts a lifetime.  

But here’s the catch: metal roofing is unforgiving. Every seam, every panel, every detail is visible. When a roofing contractor cuts corners, you can see it from the driveway. When they don’t understand expansion and contraction, you can see it from the street. And when they don’t know how to work with copper or custom metal roofing panels, you could be living with the consequences for decades. In the Bay Area, where homeowners are investing in premium materials, the difference between a skilled metal roofing contractor and a low-bid installer becomes painfully obvious. 

The “Things You Can’t Unsee”: A Field Guide to Bad Metal Roof Installations

Here are the most common visual red flags that indicate a standing seam metal roof was installed by someone who didn’t understand the craft. 

1. Crooked or Misaligned Seams 

Standing seam metal roofing is all about clean, straight lines. When seams wander, taper, or don’t line up correctly, it is clear the installer didn’t properly lay out the panels. This isn’t a cosmetic issue — crooked seams can create uneven stress points, leading to premature wear and leaks.   

2. Oil Canning 

Oil canning is a visual effect in metal roofing that makes the flat areas of a metal surface look like they are wavy or rippling. While this is a cosmetic issue and does not impact the durability or performance of the roof, it does create a distorted look that takes away from the aesthetic appeal of a metal roof. 

Light oil canning can be normal; however, excessive oil canning usually means:

• Stresses to the metal during the manufacturing process

• Over-handling of the panels 

• Installers did not account for expansion and contraction

• Substrate not properly prepared/ inconsistent substrate support

• Incorrect installation of fasteners, such as over- and under-tightening screws   

3. Sloppy Flashing Around Chimneys, Skylights, and Walls

In metal roofing, flashing is a thin, durable metal strip that is custom fitted to angles and intersections on a roof. It is installed in areas that are prone to leaks to redirect water away from those vulnerable points and prevent any damage. 

Flashing is where inexperienced installers get exposed. Poorly cut, poorly bent, or poorly sealed flashing is a sure recipe for leaks. On a metal roof, flashing should look crisp, tight, and intentional. If it looks like metal roughly hammered into place, you’re looking at a future metal roof repair.  

4. Fastener Problems

Standing seam metal roofing is designed to hide fasteners beneath the panels. If you can see screws on the top of the panels, something went wrong. Exposed fasteners compromise the roof’s weatherproofing and can dramatically shorten the lifespan of the roof. 

It is also crucial that fasteners are snug but not overtightened. Overtightening can damage panels, cause oil canning, distort seams, and create a risk for leaks. Under-tightening can cause the panels to move, also leading to leaks and premature wear.

5. Expansion and Contraction

When installing a standing seam metal roof, the contractor must understand the impact of thermal expansion and contraction. When heated, metal will naturally expand, and when cooled, it will contract. Because of this, standing seam metal roofs are designed to move with any temperature changes. However, if they are not installed correctly and designed to accommodate movement, it can lead to long-term damage, such as oil canning, leaks, panel movement, and other structural issues. 

Why These Mistakes Happen: The Craftsmanship Gap

Standing seam metal roofing is not the same as installing asphalt shingles. It requires: 

• Specialized tools 

• Sheet-metal training 

• Knowledge of expansion and contraction 

• Precision panel layout 

• Custom fabrication skills

• Extensive experience with copper, steel, and aluminum

Many Bay Area contractors offer metal roofing without having true metalworkers on staff. They rely on pre-made parts, guesswork, or “good enough” shortcuts, and few have the years of hands-on experience and specialized equipment to do it right. 

What’s Fixable vs. What’s Permanent

Not every flaw means you need a full replacement. Here’s a quick guide:

Fixable Issues: 

• Minor oil canning

• Loose trim or ridge caps

• Loose or damaged fasteners

• Small flashing corrections

• Isolated panel replacement 

• Minor metal roof repair 

Permanent Issues:

• Major oil canning

• Severe corrosion or rust 

• Crooked seams

• Thermal stress damage 

• Mismatched panels or paint systems

• Structural flashing failures

• Improper clip spacing or fastening

A skilled metal roofing contractor can evaluate whether your issue is cosmetic, functional, or structural — and recommend the right solution. 

Why Custom Copper and Sheet Metal Roofing Gets It Right 

At Custom Copper and Sheet Metal Roofing, metalwork isn’t a side service — it’s the foundation of what we do. Our work has been officially highlighted by the Copper Development Association Inc., a distinction reserved for contractors who demonstrate exceptional skill, technical mastery, and leadership in copper and metal roofing. This recognition reinforces what our clients already know: CCSMR is a trusted authority in the field of custom copper and sheet metal roofing. 

That level of expertise doesn’t just happen overnight. Built on generations of artisanal craftsmanship, CCSMR has been serving the San Francisco Bay Area for over 18 years. This long history gives us an unparalleled depth of knowledge. When you hire CCSMR, you’re not just getting installers. You’re getting true craftspeople who understand how different metals behave, how to minimize oil canning, how to design with expansion and contraction in mind, and how to create clean architectural details that elevate your home.    

See Something You Can’t Unsee? We’ll Tell You Why

Metal roofing mistakes are visible — and often permanent. If something on your roof looks off, crooked, wavy, mismatched, or just not right, trust your instincts. A standing seam metal roof should look clean, straight, and intentional from every angle. 

If you’re concerned about the quality of your metal roof or planning a new installation, schedule a consultation with Custom Copper and Sheet Metal Roofing. We’re the Bay Area's trusted experts in all things copper and metal roofing.