Weathered unpainted galvanised/Zincalume

Resene Popular Paint Systems –
Roofing products and roof paint preparations: training notes

This web page is an edited version of the Resene Best System Selling training notes provided to Resene staff and is provided to enable you to gain a greater understanding of the substrates and paint systems you may encounter in your decorating project. It is impossible to cover all decorating scenarios in a single document, so if you are in doubt about any aspect of your project please contact Resene for assistance.

How to paint weathered unpainted galvanised/zincalume

Note: Refer to the PDF flowchart for a visual of the steps below:

  1. Wash thoroughly using Resene Roof Wash and Paint Cleaner then rinse thoroughly

  2. Apply Resene Galvo One (apply 2 coats in exposed marine environments)

  3. Wash between coats if salt is suspected - Refer notes

  4. Topcoat options:

Weathered unpainted galvanised/zincalume

1 To optimise the benefits of the Resene Cool Colour topcoat use Resene Cool Primer.

Things to consider:

  • What sort of roof do you have?
  • Is your roof painted?
  • Do you know when it was last painted?
  • Is it faded or chalking?
  • Do you live close to the sea, say within 500 metres?
  • Is access a problem?
  • What is the fl oor area of your house?
  • What colour do you have in mind?
  • Have you considered Resene Cool Colour paints?


  • Just when a galvanised roof should be considered ‘weathered’ is a judgement call. Typically weathered galvanised iron or Zincalume will be dull, almost mottled in appearance. Almost certainly white rust will be starting to form.

  • Resene Galvo One is much better at dealing with white rust than the waterborne Resene Galvo-Prime and Resene Cool Primer. So if the roof has been left unpainted for approximately 6 months, use Resene Galvo One. If it is close to the sea (1km) then a second coat is highly recommended.
  • Old unpainted roofs will eventually start to rust as the protective galvanising layer erodes and the iron is exposed. If it is not too bad, say a ‘dusting’ of red rust in a few places, rather than a heavy red rust colour, then apply a second coat of Resene Galvo One on these areas. Alternatively Resene Galvo-Prime or Resene Cool Primer may be used as the second coat.

  • Any salt that is deposited on the roof between coats or after preparation must be rinsed away. In practise this means if the roof is near the sea and there has been an on shore breeze, hose the roof down and allow to dry before applying the next coat.

Key accessories essential to complete the job

  • PAL corrugated roller kit (if painting corrugated iron)
  • Resene black 75-100mm brush for cutting in flashings and the ends of sheets, Haydn Genius or PAL Legend if painting longrun on trough sections
  • Resene Hot Weather Additive
  • Resene Roof Wash and Paint Cleaner
  • Roller extension pole
  • Turps for Resene Galvo One

Add-ons – to make the job easier or quicker

  • Gloves
  • Hand cleaner
  • Paint pots (especially when 10 litre pails are bought)
  • UV protection

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