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AS 1562 (metal roofing): the standard behind every metal sheet roof

AS 1562.1:2018 sets the design and install rules for metal sheet roof and wall cladding: fixing patterns, minimum pitches, wind testing under AS 4040.2.

By Dan Waring. Last updated 16 May 2026. Verified 16 May 2026.

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In plain English

AS 1562.1:2018, Design and installation of sheet roof and wall cladding, Part 1: Metal, is the Australian Standard for metal sheet roof and wall cladding: Colorbond, Zincalume, painted steel, and aluminium sheet products in profiled formats like Custom Orb, Klip-Lok, Trimdek and Spandek. It pairs with AS 2050 (which covers tile roofing). NCC 2022 Volume Two calls AS 1562.1 for metal cladding installation; non-compliance fails frame inspection (verified 2026-05-16).

The three big-picture builder takeaways from AS 1562.1:

  1. Minimum pitch is profile-specific. A Custom Orb roof has a different minimum pitch from a Klip-Lok roof, which is different again from a Spandek. The roofer reads the profile spec; the builder confirms the pitch from the truss design.
  2. Fixing density scales with the wind classification. Like AS 2050 tile roofing, the fixing density rises with wind class. Coastal cyclonic sites demand far more fixings per square metre than suburban sheltered sites.
  3. The wind-load resistance test under AS 4040.2 is what supports the manufacturer’s wind ratings. Each profile is rated for a specific span and span-times-wind-class envelope; outside that envelope, the manufacturer’s warranty does not apply.

What it requires

For the metal roofer:

  1. Pitch verification at install. Common profile minimums:
    • Custom Orb (corrugated): 5 degrees minimum (rule-of-thumb; check current product data sheet).
    • Klip-Lok (concealed-fix interlocking): 1-2 degrees minimum (low-slope capable).
    • Trimdek: 3-5 degrees minimum.
    • Spandek: 3-5 degrees minimum.
  2. Fixing density per the manufacturer’s table for the wind classification (per AS 4055 and AS/NZS 1170.2). Edge zones get higher density than internal field zones.
  3. End-lap and side-lap minimums per the profile. End-laps require sealing in low-pitch installs and on cyclonic-region jobs.
  4. Underlay (sarking) installation per AS/NZS 4200.2 below the metal sheet, fixed taut and lapped per direction-of-flow.
  5. Penetration sealing at every flashing, every roof-mounted item (vents, antennas, solar PV brackets) using compatible sealant and metal materials.
  6. Flashing installation at all junctions (ridge, hip, valley, parapet, wall abutment, eaves).

What it doesn’t cover

  • Tile roofing. That’s AS 2050.
  • Membrane flat roofing. AS 4654 series covers external waterproofing membranes; AS 1562 is sheet metal-specific.
  • Solar PV array mounting. AS/NZS 5033 covers the PV-specific mounting and electrical; AS 1562.1 still applies to the surrounding metal cladding.
  • Skylights and roof windows. Manufacturer specification and AS 4285.
  • Coating durability. AS/NZS 2728 covers prepainted metal sheet durability; AS 1562.1 calls it up.

Practical implications

  • Substituting profiles without re-checking pitch is the most common frame-inspection defect. A roof framed for Trimdek at 3 degrees doesn’t suit Custom Orb at 5 degrees minimum; the substitution requires either a re-pitched truss or accepting a Performance Solution.
  • Long-run sheets are sensitive to thermal expansion. A 12 m run of Custom Orb expands and contracts noticeably across seasons. The fixing detail under AS 1562.1 allows for this in some profiles via concealed clips (Klip-Lok); face-fixed profiles (Custom Orb) need the manufacturer’s spec on fixing pattern to accommodate movement.
  • Coastal sites need 316 stainless or coated fasteners. Galvanised standard fasteners corrode in marine environments within 3 to 5 years and cause “rust stain” defects below each fastener.
  • Mixed metals are a galvanic-corrosion risk. Copper flashings on a Zincalume roof, or aluminium fasteners through Colorbond, cause electrolytic corrosion. AS 1562.1 references metal-compatibility tables.
  • The wind-load-rated span is a hard limit. A profile rated for a 1,200 mm batten centre at N3 cannot be fitted at 1,500 mm centres in the same wind class. The roofer reads the manufacturer’s wind-load table and matches the batten layout.

References

See also

Last updated: 2026-05-16. Verified: 2026-05-16. Quarterly review for currency.

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