Timber Lot Grades
Class A
- Highest quality grade
- Devoid of any significant knots within the Clear Wood Cutting area
- Unparalleled for the finest woodworking projects
- Equivalent to PRIME or SUPER PRIME Grade
- >155mm x >2000mm clear wood (free of knots) within each board
- Select either Waney Edge (also known as Live Edge) or Square Edge
- Planed All Round available on request.
Class B
- High quality timber with some character
- Equivalent to Common Grade
- Some knots expected
- Splits outside of clear wood area possible
- >155mm x >1000mm clear wood (free of knots) within each board
- Select either Waney Edge (also known as Live Edge) or Square Edge
- Planed All Round available on request.
Class C
- Class C is an aesthetic choice enriched with knots and a natural feel
- Ideal for projects that desire a natural or rustic appearance, consistent with the No. 2 Common grade
- Select either Waney Edge (also known as Live Edge) or Square Edge
- Planed All Round available on request.
National Hardwood Lumber Association (NHLA)
- Characteristics:
- At least 83.3% (or 10/12ths) clear cuttings.
- Minimum size of clear cuttings: 76 mm x 2134 mm (4″ x 5′ or 3″ x 7′).
- Minor defects are allowed but should be small and few.
- Best appearance and consistency in colour.
- Characteristics:
- Minimum size board: 102 mm x 1829 mm (4″ x 6′).
- Provides a long clear cutting on one edge and a minimum of 76mm (3″) on the other.
- At least 83.3% clear cuttings on the poorer face.
- Often used when FAS grade is not necessary or for mouldings, joinery, etc.
- Characteristics:
- Allows for some knots and imperfections.
- Minimum size board: 76 mm x 1219 mm (3″ x 4′).
- At least 66.6% (or 8/12ths) clear cuttings.
- Clear cutting sizes: 76 mm x 914 mm or 102 mm x 610 mm (3″ x 3′ or 4″ x 2′).
- Popular for furniture making due to its more rustic appearance and cost-effectiveness.
- Characteristics:
- Minimum board size: 76 mm x 102 mm (3″ x 4′).
- At least 50% clear cuttings.
- Clear cutting sizes: 76 mm x 610 mm or 102 mm x 305 mm (3″ x 2′ or 4″ x 1′).
- Allows for larger knots and other imperfections.
- Often used for rustic-style furniture, paneling, and some flooring applications.
Overview of Industry Timer Grading Agencies
British Standards Institute’s (BSI) & European Standards References for Timber Grading and Quality
BS 1186-3: Timber for and workmanship in joinery – Part 3: Recommendations for the specification of solid timber.
BS 5756: Specification for visual strength grading of hardwood.
BS 4978: Visual strength grading of softwood.
BS 5268 (Multiple parts): Structural use of timber.
BS 8605 (Multiple parts): External timber cladding.
BS 1088: Marine plywood.
BS 1297: Specification for preservative-treated timber.
BS 5440: Structural grading of timber.
BS 8001: Circular economy. Guidance for organizations.
BS EN 13183 (Multiple parts): Moisture content of a piece of sawn timber.
BS EN 14081 (Multiple parts): Strength-graded structural timber with rectangular cross-sections.
BS EN 13556: Round and sawn timber – Nomenclature of timbers used in Europe.
BS EN 350: Durability of wood and wood-based products.
BS EN 384: Structural timber – Determination of characteristic values of mechanical properties and density.
BS EN 408: Timber structures – Structural timber and glued laminated timber – Determination of some physical and mechanical properties.
BS EN 975-1: Quality classes of oak and beech sawn timber.
BS EN 1912: Structural timber – Strength classes – Assignment of visual grades and species.
BS EN 14080: Timber structures – Glued laminated timber – Requirements.
BS EN 16737: Structural timber – Visual strength grading – Sawn spruce timber from Scandinavia, Central Europe and North America.
National Hardwood Lumber Association (NHLA)
Grading Agencies:
SPIB Grading Rules for Southern Pine Lumber: Covers the classification of Southern Pine lumber.
WWPA Rules for Western Lumber: Provides grading standards for softwoods from the Western states, including species like Douglas Fir, Hem-Fir, and Spruce-Pine-Fir (SPF).
WCLIB Standard Grading Rules for West Coast Lumber: Similar to the WWPA, but may cover additional or slightly different species or regional varieties.
Redwood Inspection Service (RIS) Grading Rules: For California Redwood.
Northeastern Lumber Manufacturers Association (NeLMA): Produces standards for Eastern White Pine and other northeastern softwoods.
Northern Hardwoods and Pine Manufacturers Association (NHPMA): Governs some softwood species, especially pine varieties, in the northern regions.
Other Standards:
American Wood Protection Association (AWPA) Standards: While not strictly about grading, the AWPA produces standards on wood preservation, which impacts the quality and end-use of lumber.
ASTM D245 – Standard Practice for Establishing Structural Grades and Related Allowable Properties for Visually Graded Lumber: Provides a method to establish structural grades for lumber.