Why steel
Strength per rupee and per kilogram, in sections that are widely available, predictable in behaviour and straightforward to connect. It can be welded, bolted, cut and modified, and a competent workshop can do all of it.
For canopies, support frames, mezzanines, industrial buildings and the secondary steel that façades and glazing hang from, it is almost always the right answer.
Protection is the whole conversation here
Steel corrodes. In coastal Mumbai it corrodes quickly, continuously, and from every cut edge and fixing.
Hot-dip galvanising. Immersion in molten zinc gives a metallurgically bonded coating that protects sacrificially — even at a scratch. The workhorse specification.
Metallising. Thermally sprayed zinc or aluminium, used for very severe exposure or for members too large for a galvanising bath.
Paint systems. Specified by exposure category — primer, intermediate and topcoat, with the film thickness stated and measured. On its own, adequate for sheltered internal work; over galvanising, excellent for seafront exposure.
The common and costly mistake is specifying a warehouse’s protection for a seafront canopy. Exposure category has to be established honestly at the start.
Cut edges and details
Corrosion starts where the coating is thinnest or broken:
- cut edges and drilled holes, if made after coating
- welds, which burn the coating off locally
- water traps — details that hold water rather than shedding it
- contact with dissimilar metals, which drives galvanic corrosion
Good detailing avoids traps, keeps fabrication ahead of coating wherever possible, and isolates dissimilar metals. Those decisions matter more to service life than the grade of steel does.
Connections
Welded. Stiff, continuous, and visually clean. Done in the workshop under controlled conditions.
Bolted. Allows transport in sections, erection in sequence, and dismantling later. Site connections are usually bolted for exactly these reasons.
Where it goes
Entrance canopies and porte-cochères, support structures for glazed roofs and structural glazing, mezzanine floors, plant screening frames, balustrade support, and pre-engineered buildings.
Where the finish is the product and it will be seen and touched, stainless steel is usually specified instead.