Trade walkthroughs
How to inspect metal panel cladding
Metal panel cladding — whether a rainscreen, a composite panel, or an insulated metal panel — is a face over a drainage plane, and it only performs if that plane and its flashings were built right underneath. The panels manage most water and let the WRB behind them handle the rest. So the inspection follows the assembly in from the barrier: WRB, flashings, sub-framing, then the panels and their joints.
For the superintendent or envelope lead verifying rainscreen, composite, or insulated metal panel systems against the shop drawings and the manufacturer's details.
Step by step
Verify the WRB, air barrier, and flashings behind the panels
Before sub-framing goes up, confirm the WRB and air barrier are continuous and lapped, and that head, sill, jamb, and transition flashings are installed and tied into the barrier. The panel system is the rainscreen; this plane is the actual line of defense.
Check sub-girts, clips, and the drainage cavity
Confirm sub-girt and clip type, spacing, fasteners, and any thermal isolation match the shop drawings, that they're aligned and shimmed to plane, and that the cavity depth for drainage and ventilation is maintained. Out-of-plane sub-framing telegraphs straight through flat metal panels.
Confirm panel product, gauge, and finish
Verify the panel is the specified product, gauge, and finish per the submittal, and check for oil-canning, edge damage, scratches, and protective-film removal before it's set. Note panel direction and orientation so the finish reads consistently.
Inspect panel attachment and engagement
Confirm panels are fastened or engaged per the system — concealed clips fully seated, exposed fasteners with the right gasketed washers not overdriven, and interlocks fully engaged. A partially engaged interlock or overdriven fastener is a leak and an uplift failure waiting for wind.
Verify joints, reveals, and gaskets
Check panel joints, reveals, and any gaskets or wet seals for the specified dimension and alignment, and confirm the system's own water management — internal gutters, baffles, or drained joints — is intact. Consistent reveal lines are both an aesthetic and a performance check.
Check terminations, closures, and penetrations
Confirm closures at the base, parapet, corners, and openings are the specified profiles, that trim and coping laps shed water, and that every penetration through the panels is flashed and sealed into the barrier, not just caulked at the face.
Confirm expansion, movement, and dissimilar-metal isolation
Verify movement joints are provided where the panel runs are long, and that dissimilar metals are isolated to prevent galvanic corrosion. Metal moves with temperature — a run pinned solid at both ends will buckle or tear its fasteners.
Document the concealed layers and punch
Photograph the WRB, flashings, and sub-framing before the panels cover them, record panel engagement and terminations, and write up oil-canning, damage, or failed seals as punch or nonconformance items before the wall is signed off.
What gets missed
- Inspecting the panel face while the WRB and flashings behind it were never verified or photographed.
- Out-of-plane sub-girts that telegraph as waviness and oil-canning through flat metal panels.
- Interlocks left partially engaged or exposed fasteners overdriven through the gasket.
- Dissimilar metals in contact with no isolation, setting up galvanic corrosion.
- Long panel runs pinned with no movement joint, so thermal expansion buckles the field.
Questions people ask
- What's a rainscreen and why does it change the inspection?
- A rainscreen is a cladding held off the wall on a drained, vented cavity so the panels shed most water and the WRB handles the rest. It shifts the inspection focus to the cavity, the WRB, and the flashings behind the panels — not to making the panel joints watertight on their own.
- What causes oil-canning and is it a defect?
- Oil-canning is visible waviness in the flat area of a metal panel, driven by out-of-plane substrate, over-fastening, or the material itself. Whether it's a rejectable defect depends on the spec and the mock-up, so set the acceptable standard with the mock-up before the crew clads the whole building.
Terms worth knowing
Checklists that make this a one-tap job
Free, field-ready checklists, each with the photo every item needs before it can be submitted.
Related guides
- How to inspect the building envelopeInspect the envelope as a system — air barrier, water-resistive barrier, flashing, transitions, and sealants — with the continuity and mock-up that make it perform.
- How to inspect EIFS and stuccoInspect EIFS and stucco from the drainage plane out — WRB and flashing, lath or board attachment, base coat and mesh, joints, and finish — before the wall can't be opened.
- How to inspect a curtain wallInspect a curtain wall as a drained system — anchors, framing, gaskets and pressure plates, glazing, and the weep path — against the details and the approved mock-up.
Reading the steps is one thing. Proving you walked them is the job.
RTI holds the submit button until every mandatory item is answered and the photos are attached, then chains the record so it can be proven untouched later.