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AS/NZS 1214: hot-dip galvanised coatings on threaded fasteners

AS/NZS 1214:2016 sets HDG coating thickness, finish, and test methods for threaded fasteners in external decks, pergolas, and structural connections.

By Chalkline. Last updated 29 May 2026. Verified 29 May 2026.

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AS/NZS 1214 is the joint Australian and New Zealand standard for hot-dip galvanised (HDG) coatings on threaded fasteners. The current edition is AS/NZS 1214:2016. It defines the minimum coating thickness, finish, dimensional tolerances after coating, and test methods for HDG bolts, screws, nuts, and washers used in external residential and structural applications. The NCC calls this standard up via the ABCB Housing Provisions where fasteners are required for tie-down and structural connections.

Where AS/NZS 1214 applies

  • External decks and pergolas: post-base bolts, ledger bolts, joist hangers’ bolts.
  • Tie-down fasteners to the timber-framing tie-down schedule.
  • Structural steel connections in non-coastal locations (coastal moves to stainless 316L).
  • Coach screws and anchor bolts at external substrate connections.

AS/NZS 1214 vs AS/NZS 4680

The two HDG standards apply to different products:

  • AS/NZS 1214 is for threaded fasteners (bolts, screws, nuts). Coating thickness specified to suit the thread tolerance.
  • AS/NZS 4680 is for fabricated steel articles (the steel members, plates, brackets the bolts go into). Thicker coating allowed because there’s no thread to clog.

A pergola job uses AS/NZS 4680 HDG on the steel post + bracket and AS/NZS 1214 HDG on the bolt that holds the bracket to the timber. Same hot-dip process, different coating-thickness regimes.

What the standard controls

  • Minimum coating mass per unit area (relates to coating thickness).
  • Finish (free from sharp protrusions, gross defects).
  • Dimensional accommodation: fasteners are oversized before coating so the post-coat thread fits standard tolerances.
  • Test methods: coating-mass test, adherence, dimension verification.

For a builder

  • Check the box or pack label. A compliant HDG fastener pack states the standard reference (e.g. “AS/NZS 1214:2016”) and the lot number. No reference = no proof.
  • Don’t mix HDG and zinc-plate on the same connection. Zinc-plate has far less corrosion resistance; on an external job a single zinc-plate bolt rusts and stains while the HDG ones beside it hold up.
  • Coastal = step up to stainless. AS/NZS 1214 HDG is adequate inland and suburban but rusts in salt-air locations within a few years. Use grade 316L stainless for coastal external fixings.

See also

Last updated: 2026-05-29. Verified: 2026-05-29. Quarterly review for currency.

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