BVM practical guide — 16 October 2026. Galvanized steel still needs appropriate storage after delivery. Moisture trapped between closely packed zinc-coated surfaces can produce white or grey deposits, commonly called wet storage stain. This guide helps purchasing and warehouse teams plan receipt and follow-up; product-specific manufacturer instructions remain essential.

Understand the observation

AGA describes deposits that develop on newly galvanized surfaces in damp, poorly ventilated conditions. Galvanizers Association UK notes that formation continues while the surface remains damp. Appearance alone neither proves rejection nor confirms coating compliance. Record the condition and agree how it will be assessed.

Receipt and storage checklist

BVM recommends recording lot identification, packaging condition, visible moisture, photographs and receipt time. SSAB warns that temperature changes can cause condensation between sheets or coil laps, even without rain. Do not open or separate strapped coils or heavy packs without the appropriate handling procedure.

For after-fabrication galvanized items, AGA prevention guidance favours covered, dry, ventilated storage and spacing that permits drainage and airflow. Keep items clear of wet ground. The arrangement must suit the package and remain stable; do not transfer a fabricated-section stacking method to every coil or sheet pack. Temporary surface protection does not replace proper storage.

Respond to moisture before deciding acceptance

Identify the affected lot, preserve traceability and contact the supplier. AGA Storage recommends enabling rapid drying and explains that damage depends on moisture exposure. Heavy deposits, darkened areas or red staining need an agreed assessment of remaining coating and remedial action. Do not infer acceptance limits from photographs or use an improvised cleaning chemical. Agree storage instructions, reporting arrangements and acceptance criteria in the purchase order.

Contact BVM or 0904 631 626.

References checked 16 October 2026: AGA publication; AGA prevention, 6 August 2011; AGA Storage, updated April 2021; SSAB surface-treatment guidance; GA UK Datasheet 11. AGA guidance concerns primarily after-fabrication hot-dip galvanizing; SSAB guidance relates to its metal-coated products. Cover: AI-generated BVM illustration, not a photograph of an actual warehouse or shipment.