Building Construction Handbook, Eighth Edition

The quality of softwood timber for structural use depends very much
on the environment in which it is grown and the species selected. Timber
can be visually strength graded, but this is unlikely to occur at the
construction site except for a general examination for obvious
handling defects and damage during transit. Site inspection will be to
determine that the grading authority's markings on the timber comply
with that specified for the application.

Format of strength grade markings on softwood timber for
structural uses ~
accredited certification
authority (see below)*

accredited certification
authority (see below)*

grader or company

licence number

grader or company

licence number

European

whitewood/

redwood

British spruce

grade † general structural

(SS = special structural)

kiln dried

British standard

quality reference

*Accredited certification authorities include

BM TRADA Certification Ltd. and Certification And Timber Grading Ltd.

alternative

condition indicator

BS strength

class

KD

Refs. BS 4978: Visual strength grading of softwood. Specification.
BS EN 14081: Timber structures. Strength graded structural
timber with rectangular cross section. (In 4 parts).

Materials Testing---Softwood Timber