NZ Flashing Regulations

Flashing Materials

Materials used for flashings are selected with respect to:
  • Durability specifications according to New Zealand Building Code:
    • 50 years, if installed behind claddings or non accessible
    • 15 years, if partially exposed or accessible
  • Installation site environment
  • Condititions of use
  • Surrounding materials

1. Aluminium flashings

In compliance to AS/NZS 1734 fabricated with a minimal thickness of 0.7 mm and formed from 5000 series.

2. Galvanized steel flashings

  • have a BMT of 0.55 mm
  • grade G550, or G300 for rolled or crimped flashings
  • selected for corrosion protection according to the intended exposure and conditions.

3. Aluminium-zinc-magnesium (combinations) coated steel flashings

  • have a BMT of 0.55 mm
  • grade G550, or G300 for rolled or crimped flashings
  • selected for corrosion protection according to the intended exposure and conditions.

4. Stainless steel flashings

  • Minimum thickness of 0.45 mm
  • 304 or 316 stainless steel
  • selected for corrosion protection according to the intended exposure and conditions.

5. Copper flashings

  • Minimum thickness of 0.5 mm
  • Compliance with AS 1566 regulation
  • Alloy grade C11000 or C12200

6. Lead sheet flashings

  • Comply with AS 1804
  • 304 or 316 stainless steel
  • Minimum if 17 kg/m2 unit mass

7. Zinc sheet flashings

  • Minimum thickness of 0.7 mm
  • Compliance with BS EN 988 regulation

8. Butyl rubber and EPDM flashings

Compliance with ASTM D6 134 Regulations in regard to:
  • Tensile strength
  • Elongation
  • Water absorption
  • Heat aging

9. Bituminous flashings

  • Comply with AS/NZS 2904
  • Be used only in fully concealed applications



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