Does My Steel Beam Need to Be Galvanised?

Not all steelwork needs galvanising — but some does. The key question is: will the steel be in contact with moisture?

Quick Reference

| Environment | Required Protection |
|—|—|
| Internal, heated room, dry conditions | Primer only |
| Cavity wall (e.g. shelf plate, padstone cramp) | Hot-dip galvanise 85µm, or approved paint system |
| External or semi-exposed locations | Hot-dip galvanise 85µm, or approved paint system |
| Marine / aggressive external conditions | Seek specialist advice |

What the PorthouseDean Specification Requires

The corrosion protection requirement is noted in the steelwork specification on your drawings. Typically:

– Beams within a wall opening in a heated domestic interior: red oxide primer only
– Shelf plates, padstone straps, external steelwork, and any steelwork in masonry cavities: hot-dip galvanising to EN ISO 1461, typically 85 µm average coating thickness — or a BS-compliant paint system approved by the Building Control Officer

Why It Matters

Untreated steel in a cavity wall corrodes. Over years, corrosion products expand and can cause masonry cracking and structural degradation. Getting the protection right from the outset costs very little compared to remedial action after the fact.

Practical Implications

– Advise your fabricator of the corrosion protection requirement before ordering
– If using hot-dip galvanising, factor in the lead time — steel goes to a galvanising plant and returns before delivery to site
– If a paint system is to be used instead, obtain Building Control approval for the specification before application

If the corrosion protection requirement on your drawings is unclear, contact us and we’ll clarify before fabrication begins.