The 5 Most Common Metal Roofing Installation Mistakes (And How to Avoid Them)

This article doesn't include tips about choosing a panel profile or selling metal roofing. It's about avoiding the five installation mistakes that consistently lead to leaks, appearance complaints, and warranty challenges. Whether you're installing on commercial or residential projects, the fundamentals are the same: start with the right foundation, allow for movement, maintain layout, manage laps carefully, and get transition details right.

This applies to standing seam systems such as Maxima, MasterLok-90, 138T & 238T, and Medallion I/II.

Why These Mistakes Matter

Standing seam systems are engineered to move. The clips, substrate conditions, and panel alignment all work together to allow expansion and contraction as temperatures change. When any of those steps are rushed or improvised, the roof may look fine on install day—but performance issues show up later. At that point, you're not being paid to fix them. And you have an unhappy customer.

Mistake #1: Skipping Substrate Evaluation Before Installation

Metal panels will reflect what's underneath them. If the deck or framing has dips, deflection, or uneven areas, the metal surface will show it. That's when oil canning or visible waviness becomes a concern. And those concerns typically come to the roofing contractor—not to the framer or General Contractor.

Once panels are installed, correcting substrate-related appearance issues usually requires removal.

How to Avoid It:

• Inspect the substrate before installation
• Confirm flatness and correct problems early
• Document substrate acceptance in writing
• If appearance sensitivity is high, specify striations or pencil ribs during panel selection

Striations do not prevent oil canning but can help reduce how visible it appears.

Mistake #2: Not Accounting for Thermal Movement

Metal expands and contracts as temperatures change. Standing seam systems rely on a combination of fixed and sliding conditions to manage that movement. If clips are not properly aligned with the panel system or the system is effectively pinned in multiple locations, stress builds up in the panels over time.

This can lead to seam distortion, fastener fatigue, or panel bowing—issues that typically appear after seasonal temperature swings, not during the install.

How to Avoid It:

• Identify the system's fixed and sliding conditions before placing the first clip
• Follow clip orientation and fastener selection
• If field conditions differ from the detail drawings, verify before modifying

Mistake #3: Losing Modularity During Installation

Standing seam system performance depends on consistent panel width and alignment. If the first few panels start slightly off layout, the error compounds across the roof. By the time the installer reaches a rake, wall, or transition, seams may not align, and the final panel may not fit correctly.

Fixing this usually means removing multiple panels—not just adjusting one.

How to Avoid It:

• Snap alignment control lines
• Check seam engagement and straightness frequently
• If drift appears, correct immediately—not later

Mistake #4: Treating Panel Laps as Low-Risk or Routine

Panel laps can function well, but they are one of the highest-risk details on a metal roof. Even small deviations in overlap length, sealant placement, or fastener location can create recurring leak points.

Whenever possible, panel laps should be reduced or avoided.

How to Avoid It:

• Consider onsite rollforming to produce longer panels that reduce or eliminate laps when the roof geometry and access allow
• When laps are necessary, follow the manufacturer's details exactly
• Check with your manufacturer or the installation manual for the recommended lap layout

Mistake #5: Overlooking Valleys, Penetrations, and Transition Flashings

The flat field of the roof is usually the easiest part to work with. The critical work happens where water changes direction. Valleys, roof-to-wall transitions, dormers, chimneys, skylights, and pipe penetrations require intentional shaping to manage water flow—not just sealing.

How to Avoid It:

• Review transition and flashing details before forming or cutting trim
• Use diverters, sealants, and underlayments as required by the project-specific installation details and climate
• Separate dissimilar materials to avoid corrosion
• If a flashing detail feels improvised, stop and verify before installation

Final Thoughts on Metal Roofing Installation

Metal roofing rarely fails because of the panel system itself. It fails when installation fundamentals are rushed or skipped. A large majority of callbacks tie back to one of these five preventable issues: substrate preparation, movement accommodation, alignment, lap execution, or transition detailing.

Doing the job right the first time keeps the project profitable—and keeps your crews moving forward instead of having to go back.