Standing Seam Metal Roofing

Why concealed fasteners matter

On an exposed-fastener roof, every screw is a hole with a rubber washer holding back the weather. Those washers have a service life measured in years, not decades, and a large roof has thousands of them.

Standing seam clips sit under the panel and hold it to the deck without piercing the surface. There is nothing to re-torque and nothing to fail on schedule.

Seam types

• Snap-lock — panels click together, faster to install, suited to steeper residential slopes
• Mechanically seamed — the seam is rolled closed on site with a seaming machine, the stronger and more weathertight option and the one for low slopes
• Double-lock mechanical seam, where water resistance and wind uplift performance matter most

Thermal movement is the Sacramento issue

A long metal panel on a 105°F July afternoon is measurably longer than the same panel on a December night. Standing seam systems are designed for that, with clips that allow the panel to move and eave and ridge details that do not pin it.

Installed without respecting movement, panels oil-can, fasteners work, and seams distort. This is the single most common failure we see on metal roofs here, and it is entirely an installation issue.

What a proper specification includes

• Panel gauge stated — 24 gauge is the residential architectural standard, 22 heavier still
• A PVDF (Kynar 500 or Hylar) finish rather than SMP, for colour retention under Central Valley UV
• A high-temperature synthetic underlayment, since metal runs hot and standard felt degrades
• Clip type and spacing engineered for the panel length and local wind loads
• Custom-formed flashings at every valley, hip, sidewall and penetration

Common questions