Areas of the cladding and flashings that are not rain-washed should be washed down at least once a year – washing generally keeps them in better order and increases their lifespan.

Some roof claddings require recoating every 8-15 years, but this depends very much on the cladding type and the location. Roof claddings on inland houses typically last many years longer than roofing on coastal houses very close to a sea spray zone.

Check roof claddings and flashings for:

  • corrosion
  • moss/lichen growth
  • dirt/salts
  • paint fading
  • lifted roofing/flashings
  • insufficient cover at sheet laps
  • dented or damaged roofing
  • roof tearing at fixing points
  • cracked, missing or dislodged roof tiles or shingles
  • roofing that ends short of a gutter
  • loose/missing fixings, including nail heads and washers
  • loss of stone chips on metal tile roofs
  • water ponding (flat roofs)
  • surface pitting of aluminium roofing.

 

DEALING WITH RUST

Deal with rust on profiled metal roofs as soon as you notice it. Remove the visible rust with light sanding, but do not use a wire brush. When the surface is clean and dry, paint it with a zinc-rich primer and then at least two coats of acrylic paint. See our Painting guide for more details.

If rust is extensive and the there are holes in the sheets, replace the rusted cladding with new.

 

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REPLACING ROOF CLADDING

Replacing roof cladding doesn’t always require a building consent. Take the example of a 30-year-old profiled metal roof that has proved durable and not leaked, but is looking tired and due for replacement. If it is replaced with the same type of roof – profiled metal – then a consent isn’t required.

Replacing an old heavy concrete or clay tile roof with a lighter profiled metal roof cladding does not require consent either, but care must be taken so the structure and fixings will be durable against wind uplift forces.

If a replacement is being done because the previous cladding failed within 15 years, consent will be required. Consent is also required if a new heavy roof cladding is replacing an older light roof cladding – clay or concrete tiles replacing metal tiles, for example. This is because the new roofing imposes a heavier load on the structure.

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