Identifying previous coatings

Before choosing the coating system you want for your project, it is very important to consider the previous coating and the integrity of that coating, to make sure it will be compatible with the system you are specifying.

In general, coatings are classified in the following five ways :

Build - how thick is the coating system?

  • Minimal: mean thickness < 5 micron
  • Low: mean thickness 5 - 20 micron
  • Medium: mean thickness 20 - 60 micron
  • High: mean thickness > 60 micron

Hiding power - can you see the substrate through the coating?

  • Transparent
  • Semi-transparent (translucent)
  • Opaque

Sheen - how shiny is the paint film?

  • Matt: reflectance < 10
  • Semi-matt: reflectance 10 - 35
  • Semi-gloss: reflectance 35 - 60
  • Gloss: reflectance 60 - 80
  • High gloss: reflectance > 80

Colour

For more information, visit the Colours area of our site.

Formulation

  • Water based
  • Solvent based
  • Epoxy
  • Acrylated rubber

It can often be very difficult to visually distinguish between different types of paint and decide whether they are water-based, solvent-based, acrylated rubber or epoxy. Here are some simple tests you can carry out to determine their formulation.

For further information, please see the following Standards:

  • EN ISO 7783-2 Paints & Varnishes - Coatings for Exterior Masonry (Determination & Classification of Water Vapour Transmission Rate (Permeability))
  • BS 6150 : 2006 Code of Practice for Painting of Buildings
  • BS EN 927 Coating systems for Exterior Wood
  • EN1062 Coatings for Exterior Masonry
  • BS 7664 Undercoats & Finishing Paints - publication imminent
  • BS 7965 Primers for Woodwork - publication imminent
  • (New standard incorporates BS 5082 & BS 5358)
  • BS 4765 Aluminium Primers
More information