Steel Beams along External Wall. Should They Be Galvanised (HDG) ?

bingsta on 16/11/2022 - 21:14

Was hoping for some advice from engineers out there or others with the appropriate knowledge.

We've had a rather large steel beam put in underneath a balcony (external wall) which will be enclosed in blue board and rendered over.

The engineer who drew up the design is saying it should be hot dip galvanised.

The builder is saying it doesn't need to be because it is not "exposed".

What is the standard for beams along external walls? Should they always be HDG or is it a case of "it depends"?

I would have thought HDG would give a fair bit more assurance / protection against rust as I would expect there would still be some moisture ingress even if it is "enclosed".

Thoughts appreciated and thanks in advance.

Home & Garden

Comments

  • brendanm on 16/11/2022 - 21:17
    +6

    Pretty sure I'd listen to an engineer over a builder. No disadvantage to getting it galvanised. Also make sure you keep jet fuel away from it.

    • Sleeqb7 on 17/11/2022 - 10:42

      Hmmmm, I think it's fine to keep jet fuel on/around it. No way it could melt steel beams, right?
      RIGHT?!

  • Hybroid on 16/11/2022 - 21:38

    You haven't specified what alternative material the builder used. It doesn't have to be galvanised, painted steel is acceptable depending on spec (for non-salt waterfront locations).

    • bingsta on 16/11/2022 - 22:19

      He used untreated steel and we are approximately 1 km from the beach.

      • Hybroid on 16/11/2022 - 22:23
        +2

        That's definitely not acceptable then. Refer them back to the Engineer's specification.

      • brendanm on 16/11/2022 - 23:16

        Lol, plain steel is definitely not suitable.

  • Typical16-bitEnjoyer on 16/11/2022 - 21:51

    Tell your builder to do exactly what you want them to do. I'd trust an engineer over them.

  • iand on 16/11/2022 - 22:03

    If it's been sent to an engineer for specification then the engineers specification should be followed

  • donkcat on 16/11/2022 - 22:49

    Most builds don't have nor specify HDG for non-exposed steelwork, if it's covered in blueboard and rendered it really shouldn't be exposed to the elements.
    Have you checked with the engineer as to their reason why they specified HDG? They may have assumed it was going to be exposed based on the location rather than the detail which may have been absent at the time of their design.
    Edit, I see you are 1km from the coast, bit of a grey zone there as less than 1km from coast is considered sea spray zone where corrosion is a greater threat and as such requires different considerations. Imo the engineer has played it slightly conservatively

  • AndyC1 on 16/11/2022 - 23:21

    Untreated steel rusts. The best treatment is hot dip galvanising then oil paint and dead last is no treatment.

    If the builder guarantees for 20 years that the steel will never be exposed to the elements (water or outside air) then it's okay to go with the cheaper option.

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