WOOD
A STRUCTURAL MATERIAL &
AN INTERIOR FINISHING
WOOD
 It is a construction
component
 From a TREE
- It is the tough
fibrous
cellular
substance
that
makes up most of
the
stems
and
branches of trees
beneath the bark
Parts of a Tree
Crown, the
leaves and
living
branches of a
tree
Trunk, the main
stem of a tree
apart from its
branches and
roots
 Natural Wood has certain properties that make
it an attractive building material:
1. Natural Warmth, to touch; would insulates (to
prevent or reduce passage of heat)
2. Workability, easily shaped with simple tools
3. Infinite variety; no trees, or even pieces from
same tree, are alike
4. Strength-to-weight ratio for bridges, boats,
homes and furniture
5. Flexibility; watch how huge trees bend before
the wind
6. Fire Protection; wood chars and therefore burns
slowly, doesn’t melt or crumble
7. Color; natural, through wood’s ability to receive
many types of stains and finishes
Classification of Wood:
 Woods can be generally
classified into two:
SOFTWOOD
- comes from conifers
(evergreens) which have
needles (pointed leaf)
instead of leaves
Conifer,
any
of
various
predominantly evergreen, conebearing trees, as pine, fir,
hemlock, and spruce
Evergreen, having foliage that
remains green and functional
throughout the year or through
WOOD
Softwood
DESCRIPTION
Pine and other
softwoods
come from
coniferous trees
Easy to scratch
and dent
compared to
hardwood
Has wider grain
Heat and
moisture can
cause cracking
and warping
OPTIONS
CARE &
MAINTENANCE
Can be stained
or painted
Generally light
color
Use mild
diluted
detergent and
damp cloth
Avoid abrasives
Use no-wax
polish
Classification of Wood:
 Woods
can
be
generally classified into
two:
HARDWOOD
- comes from the
broad-leaved flowering
or deciduous trees
such as cherry, maple
or oak
Deciduous,
means
shedding leaves annually
or at the end of a growing
season
most
Philippine
timber are of this kind
WOOD
Hardwood
DESCRIPTION
Used as frames
for its
compressive
strength
OPTIONS
Can be stained
or painted or
pickled
Moisture can
Large selection
cause to warp
of door styles
and shrink
Example is Tanguile
CARE &
MAINTENANCE
Use mild
diluted
detergent and
damp cloth but
not abrasives
Use no-wax
polish
Classification of Wood:
 Woods can be generally classified into two:
Notes:
 The term “hardwood” and “softwood” are often misleading because they
have no direct relation to the actual physical hardness or softness of the
wood
 In certain types, a hardwood may actually be softer than a softwood
Structure of Wood:
Structure of Wood:
SAPWOOD (Alburnum)
-it is the softer, younger outer portion of a tree that lies
between the cambium(formative layer just under the bark)
and the Heartwood
-the portion near the periphery (near the boundary), area
around the edge
-contains the living cells and takes an active part in the life
process of a tree
-it is more permeable (allows liquid, gasses to pass through)
and less durable because it contains more organic matter
than the central core of the log, it is more susceptible to
blueing fungi and wood-boring insects
-usually lighter in color than the heartwood (central portion)
Structure of Wood:
HEARTWOOD (Duramen)
-the older, harder central portion of a tree
-the central core of the log
-usually contains deposits of various materials that
frequently give darker color than the sapwood
-it is denser (tight, close together wherein it is
difficult to pass through), less permeable and more
durable than the surrounding sapwood
-more expensive because of the age which makes it
stronger
Structure of Wood:
Bark, the tough external covering of a woody stem,
branch, or root, composed of a living inner layer
called phloem and an outer bark of corky, dead
tissue
Phloem, a layer of tissue that carries food from the
leaves to the growing parts of a tree
Cambium, a thin layer of reproductive tissue between
the phloem and xylem, which produces new
phloem on the outside and new xylem on the inside
of stems, branches, and roots
Pith, the soft, central core about which first growth
takes place in a newly formed stem
Structure of Wood:
Properties of Wood:
a. Hardness
- this is measured by compression which a piece of
timber undergoes when a weight is applied to it
b. Flexibility
- the amount of piece will bend before breaking
- softwoods are generally brittle (hard) while hardwoods
are flexible
c. Strength
d. Durability
- it will long last
Note: Woods can deteriorate
Classification of Lumber:
TIMBER (Troso)
- wood suitable
for use as a
building
material
for
construction
- Log, a length
of trunk or large
limb of a felled
tree, ready for
sawing
Classification of Lumber:
LUMBER (Tabla)
- it is the wood term used in construction
- the Timber product manufactured by sawing, re-sawing,
passing lengthwise through a planning machine, crosscutting to length and grading
- therefore it is a processed wood
- it is classified by its size or dimensions measured in inches
ex: a piece of lumber measuring 2 inches by 4 inches is
called, 2”X4”
- generally they are available in even-numbered widths: 4,
6, 8, 10, 12 inches
Lumber
Rough Lumber
- is a lumber
that is saw,
edged
and
trimmed but
not surfaced
nominal
shapes
Lumber
Dressed Lumber
- is a lumber that is surfaced with planning
machine to attain a smooth surface and uniform
size
“S1S” – dressed one side; used for framing
“S2S” - dressed lumber smooth on 2 sides; used for framing
“S4S“- dressed lumber smooth on 4 sides; often used for parts
with exposed sides and carving details
Note: It cost slightly more than rough
Classifications of Lumber:
There are four available classifications:
A. STRIPS
- lumber less than 2” thick and less than 8”
wide
WOOD STRIP FLOORING
Classification of Lumber:
B. BOARD LUMBER
- pieces less than 2”
thick and at least 8”
wide
graded
for
appearance
rather
than strength
- usually used for
sidings and flooring
Classification of Lumber:
C. PLANKS/ JOISTS
- wide pieces of lumber 2” to 5” thick
- used for stair stringers and treads, floor
girders, roof girts and trusses
Classification of Lumber:
D. DIMENSION LUMBER
- pieces more than 2” and less than 5” in any
dimension
- classified for strength rather than
appearance
- usually used for purlins, joists and wall
framing
Note: of the above, the two most common classifications are
Dimension and Board Lumber
Dimension
Lumber
Lumber Measure:
It is important to realize that the stated size of lumber
is not its actual finished size
NOMINAL SIZE
- is the size of lumber when it is cut from the log
- the dimension of lumber before drying and surfacing
ACTUAL SIZE
- after cutting, the lumber is dried and then
planed on all four sides to achieve smoothness
- the finish size is therefore smaller
- also called dressed dimension
Lumber Measure:
NOMINAL SIZE
ACTUAL/ DRESSED SIZE
For Dimension Lumber:
2 x 4
1½ x 3½
2 x 6
1½ x 5½
2 x 8
1½ x 7½
2 x 10
1½ x 8½
2 x 12
1½ x 11½
For Board Lumber:
1 x 4
¾ x 3½
1 x 6
¾ x 5½
1 x 8
¾ x 7½
1 x 10
¾ x 9½
1 x 12
¾ x 11½
Lumber Measure:
- lumber is sold in lengths from 6’ up to 20’ in increments
of 2’
- special lengths greater than 20’ are also available but
cost more per board foot than the standard lengths
(available but not common)
Board Measure, lumber measurement in board
feet
- BOARDFOOT, a unit quantity for lumber equal to the
volume of a piece whose nominal dimensions are 12”
square and 1” thick
- which maybe described as the measure of a piece of
wood 1” thick, 12” wide (or 1’) and 12” long
Lumber Measure:
Board Foot
= Thickness (in) x Width (in) x Length (ft)
_________________________________________
12
- Generally used only for framing lumber
- Mouldings and Millworks are computed
and sold by Linear Foot
Board Foot
Example:
Compute the number of board feet:
a. A piece of 1” x 8” x 10’ strip lumber
1pc x 1” x 8” x 10’
----------------------12
= 6.67 or 7 bd. ft.
Conversion
Meter to Feet:
X 3.28
Ex:
3 meters X 3.28 = 9.84 feet
Feet to Meter:
/ 3.28 or X .30
Ex:
50 feet /3.28
= 15.24 or 15 meter
Sq.m to Sq.ft:
X 10.7584
Ex:
120 sq.m X (3.28)² 10.7584 = 1,291 sq.ft
Board Foot
b. 10 pcs of 2” x 6” x 8’
c. 5 pcs of 1” x 4” x 3m
d. 20 pcs of 1” x .20m x 12’
LUMBER
Three Categories of Lumber
1. Yard Lumber
- Intended for general building purposes
- Used for ordinary light construction and
finishing work
- Including boards, dimension lumber, and
timbers
- 2”X2” to 2”X12”
LUMBER
Three Categories of Lumber
2. Shop/ Factory Lumber
- lumber sawn or selected primarily for further
manufacture, graded according to the amount of
usable wood that will produce cuttings of a specified
size and quality
- intended for use in shop or mill makers
- sash, doors and cabinets
Ex: T&G, S-cut (stone cut), V-cut, Bead and moldings
like convex, concave and quarter round
LUMBER
2. Shop/ Factory Lumber
Matched Lumber, lumber
having edges dressed and
shaped to form a tongue
and- groove joint when in
laid edge to edge or end
to end
Patterned Lumber, lumber
dressed and shaped to a
pattern or molded form
LUMBER
Three Categories of Lumber
3. Structural Lumber
- used in heavy construction for load-bearing purposes
and is cut into timbers of large size
- it is made from the heartwood of the log
- for beams, stringers, and posts
WOOD GRAINS (haspe)
Main Types of Wood Grain Structure
1. Straight Grain
- fibers running in the
same direction as the
main axis of the tree
a. Edge Grain (vertical
grain)
annual
rings
run
approximately at right angle
to the face
b. Flat Grain
- when the annual rings run
more or less parallel to the
surface
Main Types of Wood Grain Structure
1. Straight Grain
c. Angle Grain
(indefinite grain)
- when the annual rings are about 45 degrees to the
face
Main Types of Wood Grain Structure
2. Inter-locked grain
- grains are in successive layers and in opposite
direction
3. Wavy or Curly grain
- constantly changing in orientation so that a line
drawn parallel to their direction appears as wavy ins
Wood Defects
- Every tree is a prey to defects from the moisture
content it emerges as a seedling to the last stages of
seasoning, and these defects can be innate
(inherent vice), such as the characteristic natural
shrinkage of wood: acquired defects occasioned by
seasonal checks, insect and fungal attack, etc. and
artificial defects caused by incorrect sawing and
seasoning
- As, however, any one defect may arise from several
causes it is more convenient to classify them as
natural and artificial.
Natural Defects:
- Emerges even in the early stages as seedling to the
last stage of seasoning, can be innate
- Natural shrinkage
- Acquired defects by seasonal checks
- Insect and fungal attack
Defects of Wood:
Decay
-caused
by
attack
of fungi
Defects of Wood:
CHECKS
- cracks or lengthwise separation across the annual
rings of growth caused by irregular shrinkage during
drying
- checks are formed when the circumference shrinks
more than the interior section of the log
Defects of Wood:
SHAKES
- these are cracks between and parallel to the
annual rings of the growth, a natural split
- Both the medullary ray and springwood cells of
ring-porous hardwoods are weaker than the
remainder, and built-in tensions are created which
tend to level out, either in the growing tree under
certain adverse conditions or in the felled tog
during seasoning
- Thus extensive splitting may occur in the weakest
links
Shakes
Various forms of shakes are common, as follows
1. Radial shakes
- the log splits from pith or heart radially along the
medullary rays, usually indicating that the tree has
passed its prime
- sawing losses can be minimized by placing the cuts
either side of the shake, always provided the growth
of the tree does not twist upon its axis, in which case
the shake become spiral, rendering the log useless for
long lengths.
- where only one shake is present it is known as a
simple “heart shake”, while two shakes in line impose
a “double heart shake”, and several a “star shake”
Various forms of shakes are common, as follows
2. Frost shakes
- project inwardly from a definite frost rib on the
cambium and are, as their name implies, the result of
severe weather
Various forms of shakes are common, as follows
3. Tangential shakes
- the soft springwood of the log splits away from the
harder summerwood caused by old age, excessive
bending under string winds, intense heat, etc.
- shakes run along part of the annual ring only
- known as cup shakes
- but when it is completely encircled then they
become “ring shakes”
Various forms of shakes are common, as follows
4. Cross shakes
- the actual rupture is across the grain
- cause by felling shatter (the sudden impact as the
felled log hits either hard ground or another fallen log)
- brittle heart or carrot heart
Defects of Wood:
KNOTS
- these are irregular
growths in the body of a
tree which interrupts the
smooth curve of the
grain
- the fibers of the tree
are turned from their
normal course and grow
around the knot at the
point of the tree
Knots are graded as follows:
a. Pin Knots
- Small knots ½” or under, often caused by the shedding of
early branches. Usually allowable in prime timber
b. Spike or Splay Knots
- Knots sliced through their length during sawing, and
commonly known as ‘slash’ knots. They are difficult to plane
up, especially in softwood, where large specimens are not
permissible in unless allowed for in the measurement
c. Encased knots
- Dead knots which are still sound and difficult to dislodge,
and often ringed with resin in softwood
d. Branched knots
- Two or three knots springing from a common center
Defects of Wood:
PITCHPOCKETS
- these are well-defined
openings
between
annual rings containing
solid or liquid pitch
- pitch veins
- resin pockets
- caused by damage to
the cambium layer
Defects of Wood:
Pith Flecks
- repeated damage to
the cambium layer by
small insects is often
healed over with hark,
and may show as small
dots or patches of brown
cork deeply buried
- they have no other
effect other than that of
unsightliness
Defects of Wood:
Rind Galls, patches of ingrowing bark
Internal Sapwood, dies ring by ring, forming
heartwood
Burls/ Burrs, twigs or witch’s broom
Canker, cause by fungoid disease
Cat Face, a partially heated fire scar
Callus, tissue formed over a wound in a tree resulting
unnatural growth incorporated in the normal wood
growth
Defects of Wood:
Artificial Defects
- all woods shrink on drying, thus creating
internal strains and stresses
- if structure is unequal or lacking in elasticity
(innate defect)
- incorrect seasoning imposes too great a
strain, then various forms of distortion,
splitting
Defects of Wood: Artificial Defects
WANE
- this is the lack of wood on the edge or corner
of a piece
Defects of Wood:
WARPING
- any variation with the
plane surface of the
piece
caused
by
unequal shrinkage of
the board
- there are several
forms of warp:
Defects of Wood:
WARPING
a. Crook
a
distortion of the board
in which the edge is
convex or concave
longitudinal
b. Bow - a distortion
of the board in which
the face is convex or
concave longitudinal
Defects of Wood:
WARPING
c. Springing
- sometimes known as
edge bend
- the wood remains flat
hut bends edgewise on
its own plane
Defects of Wood:
WARPING
d. Cup - a distortion
of the board in which
the face is convex or
concave across the
board
- rounding
e. Twist - a distortion
of the board in which
one corner is raised
Methods of Sawing Wood:
A log of wood can be cut into different ways to make
lumber
Plainsawing
- refers to lumber cut
tangent to the annual rings
or growth or, in commercial
practice, cut with annual
rings at an angle 0 degrees
to 45 degrees
- plainsawn lumber is
preferable when a pleasing
pattern is required, as in
wall paneling
Methods of Sawing Wood:
A log of wood can be cut into different ways to make
lumber
Quartersawing
- refers to wood cut radially to the annual
rings of growth parallel to the rays or, in
commercial practice, cut with the annual
growth rings at an angle 45 degrees to 90
degrees
- quartersawn lumber is desirable
because it has less shrinkage than
plainsawn lumber, and this is important
where joints must kept tight
Riftsawing
- very similar to quartersawn but
different angle
- refers to wood cut at a 30 degrees
to 60 degrees angle to the center of
the timber
SEASONING of LUMBER
Seasoning
- the process of removing moisture from
green wood (wood from freshly-cut logs)
Fiber-saturation Point
- remaining absorbed water
- approximately 30% moisture content (M.C.) for all species
Equilibrium Moisture Content (E.M.C.)
- the condition of dryness of the wood
- in the Philippines, this is equivalent to from 12 to 16 percent
moisture content
SEASONING of LUMBER
it may be done by:
a. AIR-DRYING (Natural or Sun Drying)
- in which the lumber is exposed to the air
- lumber is strip-piled at a slope on a solid
foundation to allow air to circulate around
every piece while sloping allows water to
run off quickly
a. AIR-DRYING (Natural or Sun Drying)
SEASONING of LUMBER
it will be done by:
b. KILN-DRYING
- in which warm moist air or superheated
steam is used to heat the wood and drive out
moisture
- where lumber is artificially dried to the
correct moisture content
- used for more expensive lumber, required for
more refined uses so as wood will not move
like in furniture
b. KILN-DRYING
SEASONING of LUMBER
Seasoned lumber has many advantages over
green lumber:
a. It lessens the liability of the wood to be
attacked by the fungi causing blueing and
decay, and some wood-boring insects
b. Reduction of weight
c. Increased strength
d. Minimum shrinkage after the lumber is in
place (thus avoids opening up joints in doors,
windows, sidings, etc.)
SEASONING of LUMBER
Seasoned lumber has many advantages over
green lumber:
e. Reduced checking and warping
f. Increased nail-holding power of the wood
(nails do not hold well when driven into green
or unseasoned lumber because of its softness)
g. Improvement of the wood for the application
of paint and to receive wood preservatives,
fire retardants
SEASONING of LUMBER
The advantages of kiln-drying over air-drying are:
a. Greater reduction in weight
b. Control of moisture content to any desired value
c. Reduction in drying time
d. Killing of any fungi or insects
e. Setting the resins in resinous wood
f. Less degrade (degrade is the loss in quality
during seasoning of the lumber through unequal
shrinkage which causes checks and loosening of
knots, warping)
PRESERVATION of LUMBER
- Wood can be treated to prevent or
at least delay destruction by fungi,
insects, bacteria, marine organisms,
and fire.
SEASONING of LUMBER
Pressure Treated Lumbers
- when lumber is subjected to pressure
and injected with chemicals or salts to
insure it from rots
a. WOLMANIZED- Wolman Salt
b. TANALIZED
c. PERMANIZED
d. BOLIDEN- patented lumber