Joinery timber other than those requiring preservative treatment shall be pressure impregnated.
Joinery timber shall be straight grained. Grains appearing on the surface of finished joinery work to be stained shall be of the same character.
Exposed surfaces of timber for joinery shall not have visible knots impairing the appearance of the finished surface.
Timber for joinery work not exposed to view may have knots on one face provided such knots do not affect the structural strength of the timber.
Timber that has developed visible cracks shall not be used for joinery work.
