Steel Finishes – what are they? Why should I care?

What is HGD?  

• It is an acronym for hot dipped galvanising.
• It’s when you dip steel into a bath of molten zinc. But why? To protect steel from the elements.
• Watch this video: https://www.youtube.com/watch?v=gXm9DlMfQtQ
• Note: you will need to prepare steel in order to galvanise. This may involve adding holes to the steel, in order explosions in the galvanising bath, so that air can always escape.

What is primer?

• It is a coating you apply to steel, in order to help paint stick on to it. It can also have some durability benefits e.g. preventing corrosion.
• Reference: https://www.youtube.com/watch?v=nLO-lv1mNLo

What is EPOXY?

• A type of primer.

You must follow the finish notes listed in Engineer and Architectural drawings.

If the steel is exposed to the elements, it will usually be specified as Hot Dip Galvanized (HDG). For interior structural steel, a primer coating is typically applied. And perhaps, where required, a top coat finish will be applied to make it look aesthetically pleasing.

What happens if you ignore or avoid finishes?

• Rework & Labor Costs:
  Mistakes in applying paint, primer, or epoxy can lead to complete rectivication works. HDG requires a lead time and is particularly expensive.
• Increased Maintenance: with poorly applied finishes.
• Structural Damage Repair: with mis-specified finishes.
• Legal and Warranty Implications: You could lose insurance.
• Financial Impact: Could be significant.

What is the lesson learned?

• When steel detailing, it is critical that you look carefully at the finishes of steel.