Standing seam roof

A standing seam roof is made of metal panels, typically zinc, aluminium, copper or coated steel, whose long edges are turned up and folded together with the neighbouring panel. Because the seam sits above the surface where water runs, the roof is highly weathertight. Panels are fixed to the structure below with concealed clips, so no screw heads pierce the covering.

Key features

• Concealed clips let the metal expand and contract with temperature.
• Long single-length panels mean very few horizontal joints.
• It works on fairly low pitches; the minimum slope is set by the manufacturer’s system specification.
• It can follow curved roofs and is also used as wall cladding.

Details and workmanship

How long a standing seam roof lasts depends heavily on the layers beneath it. A ventilated gap or separating membrane between metal and insulation helps prevent condensation and corrosion. Ridges, valleys, chimneys and rooflights all call for skilled detailing, and dissimilar metals must not touch, to avoid galvanic corrosion.

Visually, the seams give a roof a fine, steady rhythm. In renders, getting their direction, their thin shadows and the roughness of the metal right makes the roof read crisply; modelling the seams as real geometry rather than a flat texture usually pays off.