The choice depends on three things

  1. Environmental exposure category (ISO 12944 — C1 indoor dry to C5 marine industrial)
  2. Required design life until first major repaint
  3. Budget — galvanising is typically 2–3× more expensive than basic paint

Hot-dip galvanising — the gold standard for outdoors

Steel is dipped in molten zinc at ~450°C, forming a metallic bond several iron-zinc layers deep. Typical thickness: 70–120 µm. The result:

  • Self-healing at scratches (zinc cathodically protects exposed steel)
  • Lifetime in C3 environment (urban/industrial): 60+ years
  • Lifetime in C5 environment (coastal industrial): 25–35 years
  • Cost: typically €350–600 per ton of steel

When to use: outdoor structures, coastal/chemical environments, places where periodic repainting is impractical (height, access, downtime). Used on bridges, transmission towers, power-station structures, agricultural buildings.

Paint systems — primer + top-coat

A typical industrial paint system: blasting (Sa 2½), zinc-rich primer (60–80 µm), tie-coat, polyurethane top-coat (50–80 µm). Total dry-film thickness: 200–300 µm.

  • Lifetime in C3 environment: 15–25 years to first major maintenance
  • Lifetime in C5 environment: 8–12 years
  • Cost: typically €150–250 per ton
  • Wide colour selection (RAL)

When to use: indoor structures, dry-warehouse environments, projects where galvanising is over-spec, situations where colour matters (architectural visibility, brand colours).

Duplex systems — galvanising plus paint

Galvanise the steel, then paint on top. The paint protects the zinc; the zinc protects the steel; total lifetime is the sum, not the larger. Used on structures that need to look good and last long — bridges, sports stadia, premium architectural projects.

  • Lifetime in C5 environment: 35–50 years
  • Cost: typically €450–750 per ton

Common mistakes we see

  • Over-spec. Specifying duplex on an indoor warehouse — wasted money.
  • Under-spec. Specifying basic paint on a coastal site — major repaint within 5 years.
  • Field touch-ups poorly done. Welds and bolt connections lose factory coating; field repair must use the same system, blasted and applied properly.
  • Ignoring crevices. Lap joints, hollow sections, faying surfaces — moisture traps that need attention regardless of system.

Our typical recommendation

For most Turkish industrial sites:

  • Indoor dry warehouse (C2): primer + top-coat, total 180 µm — 20+ year life
  • Outdoor industrial (C3): galvanise OR heavy paint system — 25 year life
  • Coastal / chemical (C5): galvanise, ideally duplex — 30+ year life

Send us your environment and required design life — we'll spec a coating system to match the budget.