Standing Seam Clips (Fixed and Sliding)

Clips are the concealed connections between standing seam panels and the deck or purlins below. Each clip is screwed down and has a tab that is captured in the seam of the panel. Clips resist wind uplift and, just as importantly, decide how the panel is allowed to move as it expands and contracts.

Types

• Fixed clips: a single piece that locks the panel in place. Panels may be fixed at one zone only (often near the ridge or mid-slope) so that they move away from that point.
• Sliding, expansion or floating clips: usually two-piece, with a base fixed to the structure and a tab that can slide within it, allowing the panel to travel lengthwise. They are particularly important on long panels and on aluminium, which moves the most.
• Cleats: in traditional copper, zinc and terne roofing, small strips of the same or compatible metal, often at about 12 in (300 mm) centres, do the job of clips. Specifications call for fixed or expansion cleats designed not to unhook under thermal movement.

Selection

Clip choice and spacing depend on the specific system and its manufacturer's specifications, the panel profile, the metal, the deck type, local codes and the design wind load. Corner and perimeter zones usually need closer spacing. One federal specification for copper roofing requires multi-piece clips for panels wider than 12 in and stainless steel screws, with nails not permitted for clip fastening. Bearing plates are sometimes used under clips on insulated assemblies.

Industry guidance

The Metal Construction Association's best practices guide for standing seam roof clips, published in 2018, addresses selecting and using clip connections so that systems accommodate thermal movement and resist attachment fatigue. As the association put it, correct attachment is central to the long-term performance of metal roofs.

Common mistakes

Using only fixed clips on long panels, mixing clip types from different systems, over-tightening or misaligning clips, and fastening through panels at both ends all restrain movement and can lead to oil canning, clip failure and seam damage.