1. SELECTING WOOD & LUMBER
Mandi Bañales
April 2001
Cal Poly San Luis Obispo

2. KINDS OF WOOD
Softwood comes from needle leaf, evergreen trees called conifers
Hardwood comes from broadleaf trees that lose their leaves each fall season, called deciduous trees. Kinds of Woods

3. Softwood types White pine Easy to work with, straight Yellow pine
Wear resistant and tough
Fir
Light, straight, and strong
Redwood
Excellent decay resistance
Cedar
Light and easy to split
Spruce
Light, straight, strong and resonant

4. Uses of Softwood Types
White pine – shelving, interior finish, exterior trim, and door frames
Yellow pine – benches, stairs, where semi-hard surface is desired
Fir – framing members, siding, sheathing, and gates
Redwood – posts, fences, patios, and siding
Cedar – fence posts, sills, and shingles
Spruce – aviation and musical instruments

5. HARDWOOD TYPES Oak Tough, strong, and open-grained Walnut
Beautiful, brown, open grain
Maple
Very durable and light-grained
Mahogany
Grain is straight to interlocked, texture is medium to coarse and uniform
Birch
Straight, close grain and a fine, even texture

6. Hardwood Identification
BIRCH
OAK
WALNUT
MAHAGONY
MAPLE

7. Uses of Hardwood Types
Oak - used in floors, interior finish, barrels, furniture
Walnut – used for fine furniture, boat building, clock cases
Maple – used for floors, interior finish, furniture, and guitar necks
Mahogany – is used for fine furniture, boat interiors, pianos,
Birch – used for surface veneer on cabinets and doors, Furniture, high-grade joinery, high-grade plywood

8. Log Cutting Method #1
Slash sawing cuts a log so that the annular rings form an angle of less than 45 degrees with the surface of the lumber.
Softwood lumber cut in this fashion is referred to as flat-grained
Hardwood lumber cut in this fashion is referred to as plain-sawed

9. Log Cutting Method #2
Quarter sawing cuts a log so that the annular rings form an angle of more than 45 degrees with the surface of the lumber.
Softwood lumber cut in this fashion is referred to as edge-grained
Hardwood lumber cut in this fashion is referred to as quarter-sawed

10. FINISHES
Rough lumber comes directly from the sawmill unplaned and varying in dimensions from piece to piece
S2S - lumber surfaced on two sides-all pieces to have the same thickness, but varying widths
S4S – Lumber surfaced on four sides allowing exact dimension from piece to piece.

11. Special Notes for FINISHES
THE ACTUAL SIZES ARE ½ INCH LESS THAN THE NOMINAL SIZES!
Example: the actual size of a 2 x 4 is
Only 1 1/2” x 3 1/2”

12. THE BASIS OF LUMBER GRADES
APPEARANCE AND
SOUNDNESS OF
WOOD

13. Examples of Lumber Grades. These would be on the
wood at time of purchase.

14. DEFECT VS. BLEMISH
A Lumber defect is an irregularity in or on the wood that reduces its strength, durability, or usefulness
A Lumber blemish is a defect that impairs only the wood’s appearance

15. Common Lumber Defects Knots Holes Splits Shakes Pitch pockets
Honey combing
Wane
Decay
Blue Stain
Warp

16. Basic Lumber Grades Select –
Grades A & B suitable for natural finishes
Grades C & D are suitable for paint finishes
Common –
Common #1, 2, and 3 are suitable for use without waste
Common # 4 and 5 are suitable for use permitting waste

17. PLYWOOD GRADES N
Veneer with a smooth surface suitable for natural finishes A
Is a veneer with a smooth surface suitable for painting B
Is a veneer with a solid surface C
Plugged is an improved C veneer with splits limited to 1/8 inch width, and knot holes and bore holes limited to ¼ x1/2 inch
Is a veneer with tight knots to 1 ½ inch D
Is a veneer with knots and knot holes to 2 ½ inch width across the grain which is limited to interior, exposure 1 and 2 panels
G2S
Means the veneer is good on two sides
G1S
Means the veneer is good on only one side

18. Factors to Consider when Selecting Lumber
Quality construction does not require that all the lumber be of the best grade
Several grades of lumber may be appropriate in a single structure
Good economical construction requires the proper use of the lowest grade lumber suitable for the purpose