Colours in GFRC

Coloured GRC GFRC is often “coloured-through” and this is generally preferred to a GRC /GFRC with a painted surface (see also Surface Finishes and Textures). Any type of pigment, both in powder form or as water-based suspension, can be used provided it is compatible with cementitious matrix and its alkaline environment.

It is difficult to predict accurately the colour of the final hardened GRC. Production of trial mixes and prototype elements is therefore essential in order to agree on the colour and much variation in its shade will be acceptable. Coloured GRC requires a particularly high level of control of the production process to ensure a uniform distribution of the pigment within the body of the composite.