Specifies coating materials designed to cover all backgrounds and substrates in traditional materials or compliant with the standards in force, whether new or existing, bare or coated, absorbent or non-absorbent, smooth or rough, in order to prepare them to receive a paint or related system, or a bonded cover, whether specific or not. More generally intended to improve the surface appearance, they can also: - not be over-coated; - create a textured appearance or not; and - be treated/coloured or not (pigments, wax, etc.).