Galvanized carbon steel = lowest cost, fine for most outdoor/industrial decks (zinc 70–85 µm, EN ISO 1461). Stainless 304/316 = higher upfront, self-protecting, right for coastal, chemical, food and wash-down service. 316 is the chloride-exposure upgrade. The break-even is reached wherever galvanized would need frequent re-coating or early replacement.
One relies on a sacrificial coating; the other relies on its own alloy.
Galvanized carbon steel is ASTM A36 / Q235B base material finished with a hot-dip zinc coating (typically 70–85 µm, to EN ISO 1461 / ASTM A123). The zinc sacrifices itself to protect the steel and re-seals small damage, giving long, maintenance-free service in normal atmospheres — but the zinc layer is finite and eventually consumed.
Stainless steel grating (304 or 316) protects itself through a passive chromium-rich surface film and needs no coating. There is nothing to wear through and nothing to re-apply, which is exactly why it is specified where a coating would fail or shed particles — food lines, clean environments and aggressive process areas.
Both are detailed on the steel grating specifications page, which also covers the painted option for dry indoor service.
The cheapest panel is not always the cheapest deck over 20 years.
| Factor | Galvanized carbon steel | Stainless (304 / 316) |
|---|---|---|
| Upfront material cost | Lower | Higher |
| Protection mechanism | Zinc, sacrificial, finite life | Alloy passive film, self-renewing |
| Best environment | Outdoor, industrial, humid | Wet, acidic, saline, food-contact |
| Maintenance | Minimal for years; recoat eventually | Minimal; no coating to renew |
| When it wins on TCO | General benign-to-moderate service | Corrosive / hygienic service |
The galvanized route is the economical default for typical plant decks. The stainless route pulls ahead once you price in the cost of stripping, re-coating or replacing galvanized panels on a cycle in aggressive environments — or where coating failure is not permitted at all.
Three environments decide the specification.
Food and beverage. Wash-down, sanitizers and the need for a non-shedding surface point to stainless. 304 covers most food-contact decks; where there is salt brine or aggressive cleaning chemistry, 316 is the safer grade. A zinc coating that flakes is unacceptable in a processing area, so stainless is the hygienic default.
Chemical and coastal. Acid fumes, process spills and chloride-laden air attack zinc faster than it can protect. Stainless — and specifically 316 / 316L where chlorides are present — holds its passive film and avoids the repeated replacement cycle that galvanized would face.
Ordinary plant and outdoor. For the bulk of walkways, mezzanines and trench covers in normal industrial air, galvanized carbon steel is the right, cost-effective answer. The galvanized versus painted comparison explains why galvanizing beats paint here too.
Choose stainless (304 or 316) when the environment would either destroy a zinc coating quickly or demand hygienic, non-shedding surfaces — coastal and marine exposure, chemical and acid plants, food and beverage processing, and wash-down areas. In ordinary outdoor and industrial atmospheres, hot-dip galvanized carbon steel (ASTM A36 / Q235B) is the lower-cost, fully adequate choice. The upgrade pays for itself wherever galvanized grating would need frequent replacement or where coating failure is not acceptable.
304 is the general stainless grade for mild wet and food-contact service. Specify 316 or 316L where there is chloride exposure — coastal air, de-icing salt, chemical process streams — because 316's added corrosion resistance is the upgrade that keeps the passive film intact in those conditions. For most genuinely corrosive plants, 316 is the default; 304 is the economical option in less aggressive wet service.
No. Stainless protects itself through a passive chromium-rich surface film and needs no galvanizing or paint to resist corrosion. The base material is the protection, which is why it is specified where a coating would fail or shed. It can be supplied as-milled, pickled-and-passivated, or brushed for a specific look, but none of those are a corrosion coating in the way galvanizing is.
Stainless carries a higher upfront material cost than galvanized carbon steel. The payback comes from avoiding coating renewal and, more importantly, avoiding premature panel replacement in aggressive service. In a benign atmosphere the galvanized route is cheaper over the life; in a corrosive or hygienic environment the stainless route usually wins once you account for the cost of stripping, re-coating or replacing galvanized decks on a cycle.