Roof painting can enhance the aesthetic appeal of a house and extend the lifespan of a roof. The key to a successful roof painting job lies in the proper preparation of the surface.  

Follow this step-by-step guide from Plascon: 

Roof substrate types 

Firstly, understand the metal beneath the existing coating. The two main metal substrates are:  

• Galvanised substrates: Zinc coatings applied to raw steel. Zinc layers act as sacrificial metal during corrosion. 
• Zincalume: An alloy of zinc and aluminium that outperforms galvanised iron in the long term. 

Types of coatings 

Determine the presence and type of coating on the roof. Previously hand-painted surfaces require different surface preparations and primers than factory-applied coatings. Check for signs of corrosion, flaking or chalking residues. 

Check for signs of corrosion, flaking or chalking residues.

Surface preparation  

This is the most critical step in any painting project. It ensures that the paint adheres properly to the surface, providing a durable and long-lasting finish. 

• General cleaning: The first step in preparing your roof for painting is cleaning. Remove any loose dirt, dust, chalking material and debris from the roof surface. This can be done using abrasive pads in conjunction with GR1 Plascon Steeltect 7100 SB (Aquasolv Degreaser). High-pressure water jet surfaces afterwards and allow to dry. Ensure surfaces are water break-free before painting.  

Water-break test.

• Corrosion cleaning: Remove all signs of corrosion down to bare shining metal by mechanical means (sanding, grinding, etc.) or shot blasting. 

Remove all corrosion, down to bare shiny metal.

•  Repair: After cleaning, inspect the roof for any damages and repair. 

Priming  

Once the roof is clean and repaired, apply a primer. The primer helps the paint to adhere better to the surface and provides an additional layer of protection.  

Determine whether to spot prime or full prime and ensure that the primer is suitable for the type of roof material and/or previous coatings:  

Use the right paint 

Not all roof paints are created equal. The colour and/or type of roof paint can have an impact on the energy efficiency of the home. Plascon Nuroof Cool reflects heat that will protect the roof coating and colour for longer, while keeping the home cooler in the summer. 

Using the same batch per coat, apply two coats evenly and consistently to achieve full obliteration. 

A step-by-step guide to painting metal roofs. 

For more information, contact Plascon: 

Tel: +27 0860204060 

Email: advice@plascon.co.za / colouradvice@kansaiplascon.co.za 

Website: https://plascon.co.za/