Two piece vs. One-piece metal roof clips

Metal roofs are always moving. Even though it’s difficult to notice with your eyes alone – standing seam metal roofs move when the temperature changes. Even small wind gusts can cause a panel to expand or contract.

While the panel absorbs the movement by its ability to flex upward – metal roof clips work to help create a monolithic roof system that ’floats’ while making sure what’s underneath remains impervious to the elements. Today, we’re going to talk about some of those clips, how they work and how they keep your roof working in tip-top shape. Let’s jump right in!


Early versions of metal roofs were NOT designed to deal with expansion and contraction. As a result, the movement of the panels would ‘slot’ the fastener holes and cause roof leaks. Today’s versions have addressed that issue by using concealed panel clips that are designed to accommodate the movement.

That being said – there’s more to these clips than meets the eye as they all have specific needs depending on the demands placed on the roofing system, itself. Simply put – not all metal roof clips are created equal.

Two piece clips

Two piece clips are used for double-lock standing-seam roof systems. They have an upper piece that fastens tightly to the panel with a lower piece that’s fastened to the substrate. There’s a joint that connects the two pieces.

What this design allows for is panel movement and to prevent that movement from wearing out the seam sealant. Now – and this is important – while slider clips do accommodate some movement – that range of movement is limited. To get the most range out of these clips, the contractor has to apply them at a point where ambient temperature is present. A small miscalculation can impede or restrict panel movement.

The other concern with a two-piece system is the binding itself – which can cause a panel to rupture. This happens when the upper section swings out of place and can’t slide along the slip joint. This issue is most common in curved roofs.

While two piece clips are useful – their range in ability is limited depending on what your project is.

One-piece clips

One piece clips are significantly stronger and usually provide greater flexibility for panels. They also don’t require precise placement for each clip – nor do you have to depend on ambient temperature during installation.

Simply put – it’s easier, faster to install and more reliable. One-piece clips also have some other advantages like being able to prevent a panel from coming into contact with hot-melt sealant and allowing for better management of more extreme temperatures. That’s to say – one-piece clips can manage severe weather swings and the subsequent movement of your panels far better.


Together – with a well-designed system and one piece clips – you can make sure that your roofing system is practically weather-proof. Good luck!

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