Galvanised Ductwork — Built From the Right Steel
Galvanised steel is the standard material for commercial ductwork for good reason: the zinc coating protects the steel from corrosion inside and out, it takes forming and seaming without cracking, and it stays serviceable for decades in normal building environments.
We fabricate exclusively from quality galvanised sheet, cut, folded, seamed and sealed in our own Hertfordshire workshop. Because the material never leaves our control between coil and finished duct, the coating arrives on site unscratched and the duct arrives clean.
Why galvanised is the default for ventilation
Ductwork lives in unheated voids, plant rooms and roof spaces where condensation is a fact of life. Bare steel rusts; galvanised steel shrugs it off, because the zinc layer corrodes sacrificially and protects any cut edge. Galvanised duct also needs no finishing trade behind it — no priming, no painting for standard applications.
From coil to commissioning-ready
Sheet is cut and folded on our own machinery, seams are closed and sealed with oil-based mastic, stiffening beads are rolled into panels sized to need them, and Mez flanges or slip joints are fitted to order. Duct ends are sealed with blue protective film before despatch.
Both systems, one material standard
Whether your project uses rectangular trunking, spiral distribution or a mix of both, everything comes off the same galvanised coil stock and meets the same DW144 construction rules.
Frequently asked questions
Is steel ductwork the same as galvanised ductwork?
In UK commercial ventilation, yes — when a specification says steel ductwork it almost always means galvanised steel ductwork, which is what we fabricate as standard. The zinc coating is what distinguishes it from bare mild steel, giving corrosion protection without painting.
What gauge of galvanised steel do you use?
The gauge is selected per DW144 rules based on the duct's longest side or diameter — larger ducts automatically get heavier sheet plus additional stiffening. You never need to specify gauge yourself; it's built into how we fabricate.
Does galvanised ductwork need painting?
Not for standard indoor applications — the zinc coating is the finish. For exposed architectural runs we can advise on preparation if you want a painted or powder-coated appearance, and for aggressive environments alternative materials or coatings can be discussed.
How long does galvanised ductwork last?
In normal internal conditions, decades — galvanised duct routinely outlives the mechanical plant it serves. Longevity depends on environment; humid or chemically aggressive settings may justify upgraded coatings, which we're happy to advise on.
Is all your ductwork galvanised?
Galvanised sheet steel is our standard material for rectangular and spiral systems. If your specification calls for something different — stainless steel for hygiene or corrosive environments, for example — contact us to discuss what we can fabricate.