Glossary - U
Under-drawing
Describes the formation of a false ceiling by covering in roof trusses or beams with a light structure of building board or similar material.
Undercoat
A paint coating applied after the primer and before the finishing coat. In relation to timber an undercoat helps fill the grain to give a good basis for a gloss coat and in all cases the use of the right undercoat is essential to achieve the correct colour of the top coat.
Universal colourants
A colourant which can be used for thinning water-thinned and solvent-thinned paints.
Useful life
The period of time during which the paint film is still satisfactorily protecting and/or maintaining its decorative appearance.