Fixed vs Sliding Clips: What you need to know

Understanding Fixed and Sliding Clips for Standing-Seam Roofs

Fixed clips and sliding clips are essential components used to secure standing-seam metal roofs and facades. Choosing the correct clip system and installing it properly is critical to the long-term performance of the roof.

In this blog post, we will be referring to clips that are installed directly onto a timber substrate, commonly referred to as a “cold roof” assembly. Insulated roof systems, or “warm roofs” will require a different clip layout, but will not be covered.

Fixed vs Sliding Clips

Fixed clips are a direct connection between the roof substrate and the metal roof panel. They do not allow the panel to move freely with thermal expansion since they create and anchor point. If only fixed clips are used on panels of longer lengths, the expansion of the metal will stress the anchor point and can lead to unwanted problems.

Sliding Clips (aka “Expansion Clips”) are made up of 2 pieces. One that anchors to the roof substrate and the other that attached to the panel. The term sliding clip is descriptive as the clip allows space for the connection to “slide” along the length of the panel. This breathing room is critical when dealing with longer panels. Clip selection and clip placement are critical to making sure your installation is going to last decades without failure.

Why Proper Clip Placement Matters

Metal roofing naturally expands and contracts with temperature changes. Metal expands in heat and contracts in the cold. Keep in mind that temperature fluctuations in the metal are extreme compared to the ambient temperature change. Metal roofs often spend all day with direct sunlight and the surface temperatures fluctuate greatly. Proper clip placement allows the panels to move safely without causing:

• Warping
• Oil canning
• Seam failure
• Leaks
• Structural stress

Incorrect clip spacing or placement can lead to serious performance issues over time.

Consider Wind and Climate Conditions

Before installation begins, it is essential to evaluate the wind and climate zone of the project site.

As storms become more frequent and severe due to changing climate conditions, fastening requirements have become increasingly important.

For roofs with ridge heights of 10 meters (33 ft) or greater, a tighter clip spacing guideline is recommended along roof edges and corners. A common rule of thumb is the “hammer-handle length” spacing method—approximately 30 cm (12 inches) between clips.

Clip Selection by Panel Length

Panels up to 10ft long

For metal panels up to 10ft or 3 meters in length – Use fixed clips only

Panels Longer Than 10ft

For panels exceeding 10ft in length, and on roofs with a pitch of 3 degrees (.5 : 12 pitch) or greater, both fixed and sliding clips are required.

In these applications:

• A designated fixed-clip zone should be established – see chart below. This zone will be the area of the panel that is secured using fixed clips only. The rest of the panel will be secured using expansion clips.
• The fixed zone should measure between 3-5ft in length
• Sliding clips should be installed outside of this zone to accommodate thermal movement

Fixed-Clip Zone – Placement Guide

The location of the fixed-clip zone depends on the roof pitch. Since gravity will pull the panel down the roof slope, the fixed clip zone will be closer to the ridge of the roof as the slope increases. Outside of this fixed clip zone, you should be using expansion or sliding clips to ensure your panel can move without stress. Proper placement helps balance panel movement and reduces stress on the roofing system.

 

 

Quick Tip: Slightly crimp or notch the clips against the underlayment to help prevent panel movement or sliding. This ensures the panels remain securely positioned over time.