Timber Introduction in Building

1. AAR 553 STRUCTURAL THEORIES &
APPLICATIONS
TIMBER MATERIALS
MOHD HILMI FAKHRUDDIN B. ZAKARIA 2012417304
MOHAMED FIQRYN B. MD. SHAHRODIN 2012829808
MUHAMMAD FAIZ B. ABD. GHAFAR 2010121001
SHAFWANDIN BIN SHAMSUL BAHRI 2010984975
KHAIRUL ASYRAF BIN MOHD YUSOF 2010789227

2. Terminologies
• Timber – wood suitable for use as building material
• Wood – the tough, fibrous cellular substance that makes up
most of stem and branches of tree behind the bark
• Log – a length of trunk of a felled tree ready for sawing
• Lumber (timber) – timber product manufactured by
sawing, re-sawing, planed, cutting to length and grading
• Dressed lumber (dressed timber) – lumber or timber that has
been smoothed by planing machine and of uniform size
• Undressed lumber (undressed timber) – lumber that is sawn
edged and trimmed, but not planed smooth
• Treated wood – wood that has been coated or impregnated
with chemicals to resist decay and insects infestation
• Fire-retardant wood – wood impregnated with mineral salt
under pressure to reduce flammability or combustibility

3. The nature of timber
• Timber is a natural
product, drawn from
the wood in the trunks
of trees.
• Its character is
consistent with the
species of tree and the
form and growth over
time of the wood in it.
Regrowth in a native forest

4. Tree growth
• New wood on outside of tree
– oldest wood on the inside
– youngest wood on the outside
– diameter largest at the base
– one ring (layer) per growing season
• Tree in forest grows toward light
– trunk is straight
– lower branches die
– leaving small knots in wood
• Bark protects wood from damage
– the tree sheds bark each year

5. Production of wood
Pith - the start of growth in the tree
• the original sapling
Cambium - growth cells
• wood cells created on the inside
• bark cells created on the outside
Sapwood - newest wood
• on the outside of tree (~ 1-3 cm)
• takes nutrients from root to leaves
Heartwood - older wood
• cells closed - can’t pass nutrients
• storage for waste - extractives

6. Classification of Timber
• Softwood – usually found in temperate
countries (cooler climate)
• Hardwood – usually found in tropical
countries (warmer climate)
Softwood >> conifers / cone bearing plants,
needle shaped leaves, naked/exposed seed
Hardwood >> broad-leaved plants, seed
enclosed in pods

7. Variation: fibre & grain
vessels
hardwood fibres
earlywood softwood
rays
cells
latewood
rays
rays
• The cell structure is designed to serve particular functions in
a tree.
• Its properties vary in different directions.

8. Variation: species & growth
• Species and genetics:
– selected stock or natural
seed.
• Climate:
– wet or dry, cold or
warm.
• Arrangement:
– native forest or
plantation.

9. Each piece is unique
Quarter sawn hardwood
Myrtle burl veneer

10. Properties are variable
• Drying (seasoning) & shrinkage
• Strength & hardness
• Durability
• Appearance

11. Timber & Timber by-products
• Timber is available in a wide range of products
and species including:
– Solid sawn, moulded pieces;
– laminated timber;
– Veneer;
– Plywood; and
– Wood panels.

12. Solid Timber: sawn timber (lumber)
• Hardwood or
softwood.
• Solid timber cut from a
log and dried.
• It is a versatile material
used for
moulding, frames and
exposed structures.
• Size is restricted.

13. Solid Timber: mouldings
• Hardwood or
softwood.
• Solid seasoned timber
milled to a wide
variety of shapes.

14. Timber products: glue laminated (glulam)
• Small pieces of timber glued
beam together to form a larger
element.
• Used as both a structural and
finishing element.
bench top • Size is limited only by transport
capacity.
curved glulam -
Glue laminated
material can be
curved.
Curved bar

15. Timber products: veneer
• Thin layers of solid wood sliced
from a flitch or peeled from a log
and dried.
• High quality material is used as a
decorative finish.
• Lower grade material is used to
make plywood, LVL (laminated
veneer lumber) and similar products.
Veneer leaf

16. Timber products: plywood
• Layers of veneer glued
together so that the
grain direction
alternates between
layers.
• Usually produced in
sheets.
• Very good in a
structure, as a lining
and as a flooring
surface.

17. Timber products: manufactured panels
• Panels made from
wood or wood fibres
bound together with
glue, or other binder:
– Particleboard /
woodchip board
– Medium Density
Fibreboard (MDF)
MDF sheet
– Hardboard
– Core board

18. Advantages of Timber
• Environmentally friendly
material
• Good appearance, aesthetic
appeal
• Low weight to strength ratio
• Light, easy to handle, easily
joined
• Suitable for prefabrication of
components (reduce amount of
site work)

19. • Dry construction, faster
completion period
• Good sound, thermal and
electrical insulation property
• Capacity to withstand shock /
vibration

20. Disadvantages of Timber
• Subjected to rot – dry rot /
wet rot
• Is a combustible material
• Being a living material, it is
subjected to attack by
insects / termite

21. Traditional usage of timber
• Main structure of Malay
house made of “heavy
hardwood” – such as
“cengal”, “cengal mas”,
“cengal batu” and “balau”
• Floor of “balau”, “cengal”

22. • Walls made of “medium
hardwood” – such as
“meranti”
• Colonial buildings – other
species of timber such as
“keruing” and “merbau”
for structures

23. Timber usage in brick buildings
• FLOOR – floor beams /
bearers, floor joist, floor
boards
• WALL – studs, wall panel /
sheathing
• CEILING – beams, ceiling
joists

24. • ROOF – beams, rafters,
trusses, purlins, battens
• DOOR & WINDOW –
frames, door panels,
window leaves, sills
• VERANDA – balusters,
handrails, flooring, stairs,
columns