SELECTING
WOOD & LUMBER
Mandi Bañales
April 2001
Cal Poly San Luis Obispo
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
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
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
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
Straight, close grain and a fine, even
texture
Birch
Hardwood Identification
OAK
BIRCH
WALNUT
MAPLE
MAHAGONY
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
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 flatgrained
Hardwood lumber cut in this
fashion is referred to as
plain-sawed
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
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.
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”
THE BASIS OF
LUMBER GRADES
APPEARANCE AND
SOUNDNESS OF
WOOD
Examples of Lumber Grades. These would be on the
wood at time of purchase.
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
Common Lumber Defects
 Knots
 Holes
 Splits
 Shakes
 Pitch pockets
 Honey combing
 Wane
 Decay
 Blue Stain
 Warp
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
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
C
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
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