After choosing the type of metal you’ll use, and the colour, choosing the seams is the next most important decision you’ll make regarding your roof or façade.

The seams are far more than simple joins in the metal. They provide rigidity and texture to your surface, and hidden edges which can be fastened to the support structure. Equally as important they allow for expansion and contraction under different weather conditions, without stressing the seal. Here are some of the most common seams for you to choose from.

Random Angle Seam Copper Patina


Arguably one of the simplest and still among the most elegant methods of joining panels, each side interlocks with the adjoining panel (and with hidden fasteners) providing a crisp and efficient skin which is rapid to install. It’s slim profile and tight fit make it ideal for interiors as well as for exteriors.


Hook Seam


Standing seams are among the most common seam found in roofing and facades, and occur when the edges are folded away at right angles from the surface and then crimped (closed). A single standing seam employing one single fold is seldom seen, as it’s susceptible to water ingress. The two most common types of standing seam are:

  • Double Standing Seam: Where the outer skin is folded over the inner skin, and then the entire seam is folded again, and
  • Angle Seam: Where the edges are folded and then the entire seam receives a 90 degree fold. This adds rigidity to the seam, preserving it’s lines. It also creates a thicker more eye-catching seam.

Angle Seam is the norm for roofs with a pitch greater than 25 degrees, and is also popular for walls (as it’s less prone to superficial damage).


Double Standing Seam


Used almost exclusively for large flat walls, a Cassette Seam adds a unique 3-D aesthetic to any facade, with panels projecting away from the building. Although complicated to fold, it’s robust and easy to install using concealed fasteners.



Flat Lock Seams allow you to create a mosaic on your roof or façade. The panels are intricate – usually smaller and interlocking – and are laid directly against the supporting structure (usually plywood). There’s a number of ways flat-lock panels can be patterned, but the most common are Uniform, Stretcherboard (laid like bricks), or Diamond (common on roofs).



Roll Cap and Roll Seam profiles utilise a channel between the two materials which is used for fastening the material to the support structure. The channel is then capped or seamed, the difference being the amount of folding done to seal the seam (Roll-Cap utilizes pre-folded components, whereas Roll-Seam requires on-site finishing of the seam). Both methods result in a broad seam, which is quite distinctive.


Roll Cap Seam