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Rust stains on concrete/concrete block foundation walls

  • Poor quality concrete absorbing water that rusts the reinforcing, which in turns causes the concrete to spall or crack, allowing in more water 

    How to repair

  • The reinforcing was installed too close to the outer surface of the concrete

    How to repair

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Staining of walls and/or eaves

Black staining on stained or clear-finished timber weatherboards

  • Mould growth on timber surface; occurs most commonly on south-facing walls

    How to repair

Staining from run-off from cedar or H3.2 treated pine weatherboards

  • Leachate from cedar weatherboards or treatment chemicals 

    How to repair

Staining around nail holes in timber weatherboards

  • Rust staining from mild steel or hot-dip galvanised nails 

    How to repair

  • Staining from hot-dip galvanised, copper or aluminium nails in cedar (typically a teardrop-shaped stain)

    How to repair

Plywood cladding – staining around nail holes

  • Rust staining from mild steel or hot-dip galvanised nails 

    How to repair

Rust stains on stucco

  • Hairline cracking in the stucco admitting moisture causing corrosion of the reinforcing mesh 

    How to repair

Wall linings – water staining

  • Leaking roof, wall or window/wall intersection, or leaking parapet or balcony

    How to repair

  • Leaking pipe in the wall due to corrosion or a nail puncturing the pipe

    How to repair

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Timber boarding, veneered MDF or plywood – black staining

Concrete/concrete block – stains

Glass block stains

  • Alkaline run-off from cement mortar such as an external wall or where the glass block wall is part of a shower

    How to repair