layer it …

carve it…

slot it together it …..

Bend it …..

you can ……

turn it …..

• Natural warmth - to the touch; wood insulates • Workability, easily shaped with simple tools • Infinite variety; no two trees, or even pieces

from the same tree, are alike • strength-to-weight ratio for bridges, boats,

homes, furniture • Flexibility; watch how huge trees bend before

the wind• Fire protection; wood chars and therefore burns

slowly, doesn’t melt or crumble • Color: natural, through wood’s ability to receive

many types of stains and finishes

WOOD USED IN ARCHITECTURE

Natural wood has certain properties that make it an attractive building material:

a. Softwoods come from the conifers (evergreens)

which have needles instead of leaves, e.g. pine

b. Hardwoods come from the broad-leaved or deciduous trees. Most Philippine timber are of

this latter kind

CLASSIFICATION OF WOOD

Woods are generally classified into:

The terms “hardwood” and “softwood” are often misleading because they have no direct relation

to the actual physical hardness or softness of the wood, so that a hardwood may actually be

softer than a softwood.

• Sapwood: the outer portion that conducts sap and has the living cells.

• Heartwood : the inactive cells in the inner portion.

– Mineral deposits may cause darker color.

– Deposits make wood more durable.

Tree roots, branches and bark have little to no commercial value

Heart wood

Sap woodBark

a. Sapwood

STRUCTURE OF WOOD

- is the softer, younger outer portion of a tree that lies between the cambium (formative layer just under the bark) and the heartwood.

- It is more permeable, less durable and usually lighter in color than the heartwood.

b. Heartwood

1.02 STRUCTURE OF WOOD

- the older, harder central portion of a tree.

- usually contains deposits of various materials that frequently give it a darker color than sapwood.

- is denser, less permeable and more durable than the surrounding sapwood.

- The central core of the

log, it is composed of inactive cells and serves only as a mechanical support

PROPERTIES OF WOOD

a.Hardness. This is measured by the 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 while most hardwoods are flexible.

c.Strength

d.Durability.

DEFECTS OF WOOD

a. Decay – Caused by the attack of fungi.

b.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.

c. Shakes – These are cracks between and parallel to the annual rings of the growth.

Checks

Decay

DEFECTS OF WOOD

d.Knots – These are irregular growths in the body of a tree which interrupt the smooth curve of the grain. The fibers of the tree are turned from their normal course and grow around the knot at that point of the tree.

e. Pitchpockets – These are well-defined openings between annual rings containing solid or liquid pitch.

f. Wane – This is the lack of wood on the edge or corner of a piece.

PITCHPOCKETS

KNOTS

DEFECTS OF WOOD

g. Warping - Any variation with the plane surface of the piece caused by unequal shrinkage of the board. There are several forms of warp:Crook –a distortion of the board in which the edge is convex or concave longitudinal.

Bow –a distortion of the board in which the face is convex or concave longitudinal.

Cup –a distortion of the board in which the face is convex or concave across the board.

Twist –a distortion of the board in which one corner is raised.

Wood that is used in construction is called LUMBER.

CLASSIFICATION OF LUMBER

LUMBER

Lumber is classified by its size or dimensions measured in inches, for example, a piece of lumber measuring 2 inches by 4 inches is called 2 x 4.

Generally, they are available in even-numbered widths: 4, 6, 8, 10,12 inches.

There are four available classifications of lumber:a. Strips. Lumber less than 2” thick and less

than 8” wide.b. Board Lumber. Pieces less than 2” thick

and at least 8” wide.c. Dimension Lumber. Pieces more than 2”

and less than 5” in any dimension.d. Timbers. Pieces 5” or more on the smallest

dimension

The process of removing moisture from green wood (wood from freshly-cut logs) is called seasoning. Seasoning may done by:

SEASONING OF LUMBER

LUMBER

a. AIR-DRYING in which the lumber is exposed to the air.

b.KILN-DRYING in which warm moist air or superheated steam is used to heat the wood and drive out moisture.

The ideal condition in seasoning is for the moisture from the interior of the wood to replace the surface moisture which vaporizes. When the moisture from the surface escapes faster than that which travels from the interior to the surface, then there is equal drying in the board and if the difference in moisture content is big, shrinkage and then stress in the wood develops, causing seasoning checks.

SEASONING OF LUMBER

LUMBER

Seasoned lumber has many advantages over green lumber:

SEASONING OF LUMBER

LUMBER

a.It lessens the liability of the wood to be attacked by the fungi causing blueing and decay, and by some wood-boring insects.

b.Reduction of weight.

c. Increased strength.

d.Minimum shrinkage after the lumber is in place (thus avoids opening up of joints in doors, windows, siding, etc.).

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.

PLYWOOD

WOOD COMPOSITES

Wood Composites are those products made from a mixture of wood and other materials. Most wood composites are produced in large sheets, usually 1220mm (4’) x 2440mm (8’).

Plywood is the most common wood composite. It gets its name from its construction: it is made of several thin plies, or veneers, of wood that have been glued together. Each ply or veneer is glued so that its grain is at right angles to the grain of the previous ply.

The outside plies are called the face and the back, and the center plies are called the core. The cross-layering make plywood very stable and strong.

PLYWOOD

WOOD COMPOSITES

Coatings or layers of protective material over the surface are good only for interior purposes because they are not durable when exposed to the weather.

PLYWOOD

WOOD COMPOSITES

a. Standard Sizes of Plywood:

Plywood is commonly available in: 3’ x 6’ (900mm x 1800mm) and 4’ x 8’ (1220mm x 2440mm)

Standard thicknesses are: 3/16” (4.5mm) for

double wall partitions and ceilings

¼” (6.0mm) for double wall partitions

3/8” (10.0mm) for drawers and shelves

½” (12.0mm) for drawers and shelves

¾” (19.0mm) for drawers, shelves, cabinet and closet doors

1” (25.0mm) for cabinet and closet doors, and sub-floors

PLYWOOD

WOOD COMPOSITES

• the approximate equalization of strength properties along its length and width;

• greater resistance to checking and splitting; and

• less change in dimension due to moisture content

• Ordinary Plywood• Form Plywood• Marine Plywood – waterproofed• Fancy Plywood:

b. Advantages of Plywood:

c. Types of Plywood:

Narra bookmatched Kalantas Rotary cut Tanguile Ribbon-grained Lauan Rotary cut

Dao bookmatched RosewoodTanguile

HARDBOARD

WOOD COMPOSITES

This is a paneling material made by reducing and refining wood chips into small, threadlike fibers, and then pressing them under heat in hydraulic pressure into dense, smooth, and very rigid panels. In the production process the pulp is exploded under pressure. Heat and steam is applies to leave a fine, fluffy brown fibers. These fibers are transformed into mats, which are held together with lignum and other glues. The mats are than pressed between steam-heated metal plates to give grainless sheets with one smooth, glossy surface and one textured surface. To prevent warping, moisture is added in a humidification chamber.

HARDBOARD

WOOD COMPOSITES

Hardboards are a cheaper option than plywood where strength is not required.

Hardboard has a smooth surface on one side and a screened surface on the other. It is sometimes known as Masonite, after the man who invented it.

There are three types of hard board: a. Standard hardboard

is light brown in color and has a fairly hard, smooth surface on one side and a screened impression on the other. It is flexible and easy to bend. It is suitable for interior use only and where it is not subject to moisture.

b. Panel hardboard

is somewhat denser than the Standard but not as dense as Tempered.

HARDBOARD

WOOD COMPOSITES

c.Tempered hard board

is the densest type, made by impregnating standard board with tempering compound of oils and resins and baking it polymerize the tempering materials. It is dark brown in color, brittle and stiff, with improved machining qualities and greater resistance to moisture and water penetration, making it ideal for exterior use Hardboard is usually in panel size of 4’x8’

(1220mm x 2440mm) with thicknesses of 3mm 1/8” (), 3/16” (4.5mm) or ¼” (6mm), and is obtainable either with a plain, textured, or perforated surface.

Brand names of Hardboard:LAWANIT standard and tempered boards LAWANEX panel boards MASONITE standard, panel and tempered hard board

CHIPBOARD

WOOD COMPOSITES

Chipboard is made by bonding together wood particles with an adhesive under heat and pressure to form a rigid board with a relatively smooth surface, often faced with veneer. It is made by binding phenolic resin or urea formaldehyde glue.

Chipboard is available in a number of densities; normal, medium and high-density.

- Normal density is fairly soft and 'flaky‘

- High-density is very solid and hard (often used for

worktops and fire doors)

- Medium density is somewhere in between

FIBERBOARDS and MEDIUM DENSITY FIBERBOARDS

WOOD COMPOSITES

Fiberboards are finishing materials made from vegetable fibers such as corn or sugarcane stalks pressed into sheets. It is not very strong, but has good insulating properties therefore it is usually used for ceiling only.

It is generally 4’x8’ (1220mm x 2440mm) panel size, in thicknesses of 3/16” (4.5mm) or ¼” (6mm), ½” (12mm) and ¾ “ (19 mm).

Acoustic fiber board is manufactured from wood, straw, bagasse pulp pressed into boards with or without holes or slots. Thicknesses of acoustic fiber board vary from ½ “ to 2” (12 to 50mm) in ½” (12mm) increments.Brand names of Fiberboard:CELOTEX, CANEX, HOMASOTE, PHILTEX, BONOTEX

FIBERBOARDS and MEDIUM DENSITY FIBERBOARDS

WOOD COMPOSITES

MDF is a type of hardboard which is made from wood fibers glued under heat and pressure. MDF has many qualities that make it an ideal alternative to plywood or chipboard.

It is dense, flat, stiff, has no knots and is easily machined. Its fine particles provide a material without a recognizable "grain".

Unlike plywood, MDF contains no internal voids, and will produce better edges providing that it is correctly machined.

GYPSUM BOARDS

WOOD COMPOSITES

This is a non-combustible building board with a gypsum core enclosed in tough, smooth paper. It is designed to be used without addition of plaster for walls, ceilings or partitions. It is extensively used in “dry-wall” construction, where plaster is eliminated Brand Names: BORAL ELEPHANT

Square Edge (S.E.) for coverstrip jointing; visible butt - jointed panelling with clamp fixing and free suspension.

Tapered Edge (T.E.) for smooth seamless jointing; jointless wall and ceiling panelling

GYPSUM BOARDS

WOOD COMPOSITES

The types of Gypsum Board are:

a. Wall Board

This type is used for surface layer on interior walls and ceilings. The regular wallboard comes with grey liner paper backing and special paper finish on the facing and edges suitable for decoration. The foil-backed gypsum board has aluminum foil bonded to the liner paper to serve as vapor barrier and thermal insulation. Predecorated gypsum board comes with a decorative vinyl or paper sheet on its face. b. Backing Board

This is used as base layer in multi-ply construction, where several layers of gypsum boards are desired for high fire resistance, sound control and strength in walls.

GYPSUM BOARDS

WOOD COMPOSITES

c. Core Board

To save space, this type is used as a base in a multi-ply construction of self-supporting (studless) gypsum walls. It comes in 1” (25mm) thickness or 2- factory-laminated, ½ “ thick layers of backing board .

d. Type X Gypsum Board

For use in fire-rated assemblies, this may be wallboard, backing board, or coreboard made more fire-resistant by addition of glass-fiber or other reinforcing materials

e. Water-Resistant Backing Gypsum Board

This type comes with water-resistant gypsum core and water-repellant face paper. It maybe used as base for walls of bathrooms, showers, and other areas exposed to wetting.

GYPSUM BOARDS

WOOD COMPOSITES

g. Gypsum Formboard

This type is used as a permanent form in the casting of gypsum concrete roof decks.

f. Gypsum Sheathing

This type is used as fire protection and bracing of exterior frame walls. It must be protected from the weather by an exterior facing.

FIBERCEMENT BOARDS

WOOD COMPOSITES

Fiber-reinforced cement board is comprised of 72% Portland Cement, 20% mineralized cellulose fibers derived from recycled materials, and 8% calcium carbonate.

PARTICLE BOARD

WOOD COMPOSITES

Particleboard is made of small wood chips and base materials including cotton stalk, rice straw, bagasse, conventional wood chips and sawdust that have been pressed and glued together.

Particle Board Particle board is made by bonding wood chips and wood waste, sawmill shavings, or even saw dust. Made with larger pieces of wood than used to make MDF

pine oak beech walnut maple zebrawood mahogany ash