Standing seam is a way of joining sheet metal rather than a material. Panels run from ridge to eaves and are folded together at raised upstands, so the joints sit above the water rather than in it. That is why it works at pitches a tile cannot and why it appears on modern extensions, dormers and low slopes where nothing traditional would keep water out.
Standing seam metal roofing: the metals, and what each is chosen for
Four metals are used as standing seam metal roof material in Britain. Zinc is the common British choice on domestic work and weathers to a matt grey that most planning officers accept. Aluminium is lighter and comes pre finished in a colour range, which suits an extension meant to look deliberate rather than traditional. Copper is the longest lived and the most expensive and turns green over decades. Coated steel, which is what most people mean by a standing seam tin roof, is the commercial default and the cheapest per square metre. All four are formed the same way, and the price difference is the metal and the fabricator's time rather than the technique.
Where standing seam actually earns its price
Low pitches are the honest case: a covering that would need twenty five or thirty degrees to shed water safely is replaced by one that works at three or five, which is what makes a flat looking extension roof possible without a membrane. Curved and tapered roofs are the second case, because sheet can be rolled to a shape a tile cannot follow. On an ordinary steep gable roof it is an aesthetic choice, and it is a dear one.
Standing seam metal roof panels: how they are formed and held down
Each panel is a long tray of sheet with a raised edge on both sides, formed to the length of the slope so it runs ridge to eaves in one piece. Neighbouring edges are folded together into the seam by hand or with a seaming tool. Hidden clips fixed to the deck are caught in the fold, so no fixing is driven through the face of the sheet.
Standing seam metal roof installation: what separates a good one from a leaking one
Movement is the whole problem. Metal expands and contracts far more than the deck under it, so the clips have to allow the panel to move while holding it down, and the fixings at the head and foot have to be detailed for it. Underneath, a separating layer stops the metal sitting on a substrate that will hold moisture against it. Most standing seam failures are movement restrained by a well meant extra fixing, or condensation from a build up nobody ventilated.
Standing seam roof cost per m2, and why it is rarely published
Installers rarely publish a rate per square metre for standing seam, and this hub has not found one it can stand behind. The price depends on the metal, since zinc, aluminium, copper and coated steel sit far apart, then the deck and insulation underneath, the edges and penetrations to detail, and the scaffold. Ask for the metal, its gauge and the build up on the quote, so two prices compare on the same roof.
Questions people ask about standing seam metal roof
Does a standing seam roof need planning permission?
On a house, changing the roof covering material can take the work outside permitted development, and in a conservation area or on a listed building it almost certainly will. It is worth a call to the local planning authority before ordering metal.
How noisy is a metal roof in rain?
Far less than people expect on a warm deck build up, because the insulation and the boarding underneath damp the sound. It is noticeable on an uninsulated outbuilding, where the sheet is fixed to purlins with air behind it.
How long does a standing seam roof last?
Longer than most owners will need, when it is detailed for movement and ventilated correctly. The failures that shorten it are almost always workmanship at the clips, the upstands and the perimeter rather than the metal itself.
Should I use a general roofer or a standing seam roofer?
A specialist. Folding seams, setting clips for movement and detailing the ridge, eaves and abutments are sheet metal skills, and a slate and tile roofer may not have them. Ask how many standing seam roofs the firm has fitted and to see one that is a few years old.