Protective coating is where clients most often try to economise, and where that economy most reliably backfires. The UAE combines everything that attacks steel: sustained high temperature, coastal salt aerosol, seasonal humidity above 80%, and UV levels that degrade organic coatings faster than temperate climates.
Hot-dip galvanising
Molten zinc metallurgically bonded to the steel. It protects sacrificially — even if the surface is scratched, surrounding zinc continues to protect the exposed steel.
- Best for — external structural steel, pipe racks, canopies, fencing, anything unlikely to be re-coated.
- Life — typically 20–40 years in a coastal Gulf environment depending on coating thickness.
- Limits — fixed bath size, a matt grey appearance, and distortion risk on thin or asymmetric sections.
Powder coating
Electrostatically applied polyester powder, oven cured. It is a barrier coating: it protects only while it is intact.
- Best for — architectural and visible metalwork where colour matters, interior work, aluminium.
- Life — 8–15 years externally with an architectural-grade polyester; longer indoors.
- Limits — a deep scratch to bare steel will corrode and creep underneath the film.
Duplex: use both
For external architectural steel that must be a specific colour and last, the correct answer is usually duplex — hot-dip galvanise first, then powder coat over a prepared zinc surface. It costs more up front and routinely outlasts either system used alone, often by more than the two added together.
For coastal external steel that has to look like something, duplex is not a luxury. It is the specification that avoids a re-coat in year eight.
What we recommend by application
External structural, plant and utility steel: hot-dip galvanise. Visible architectural steel indoors: powder coat. Visible architectural steel outdoors, especially within a few kilometres of the coast: duplex. Stainless used for its own corrosion resistance: no coating, just the correct grade and a proper passivated finish.
