1. Timber Design:
Introduction to Timber, advantages and disadvantages
as a building material.
Structural properties of timber and engineered wood
products.
Various type of truss used in Timber structure.

2. Wood is a product that combines inspiration, beauty,
performance and environmental advantage.
Offering design options that are limited only by imagination,
its flexibility and versatility is no better demonstrated than by
the variety of applications it lends itself to.
From striking internal timber detailing to strong and cost
effective external structures, wood offers a solution to a
multitude of building and design requirements, literally
creating living spaces alive with beauty, warmth and comfort.
Environmental Credentials
Design Advantages

3. Environmental Credentials
Wood offers the builder or designer several environmental
advantages over common, alternative building materials.
Namely:
Wood is a renewable resource;
Wood products store carbon dioxide;
Comparatively, the manufacture of most wood products requires
smaller amounts of energy; and
Residues generated through the processing of wood can be reused
in a variety of positive ways.
Reducing Greenhouse Gas (GHG) emissions, wood is a building
material that can deliver the designer both environmental and
performance benefits. Thus, by ensuring sustainable forest practices
and regenerating this natural product there are real possibilities to
significantly improve the environmental credentials of the building
and construction industry by choosing wood.

4. Design Advantages:
The design advantages of working with wood are as extensive as
they are varied. From the Australian Timber Design Awards that
showcase aesthetically wowing timber based designs, to nine-
storey timber construction that utilises the latest wood
engineering innovation.
Aesthetic Appeal
Manufacturing Efficiency and Flexible
Range of Applications etc

5. Limitations/Disadvantages:
– Vulnerable to pest attacks: Timber is vulnerable to biotic forces
like termites, woodworm or wood ants.
– Prone to abiotic forces: Abiotic forces of nature like Sun, Fire,
water etc. can have adverse effect on Timber.
– Shrinking and swelling of wood: Wood has a natural ability to
absorb water which is also known as Hygroscopy.

8. The structure of natural timber
Natural timber is a natural composite material
compromising cellulose fibres in a lignin matrix.
The tensile strength of timber is greater along the
grain (fibre) than across the grain (matrix).
“Cellulose Fibres in a
Lignin Matrix”

9. Classifications of timber
Basically, trees break down into either Hardwoods or
Softwoods.
All softwoods grow in temperate forests.
Hardwoods can be either temperate or tropical.

12. Properties of wood

13. Colour
Colour shows a wide range of variation. Colour of the same kind of
timber changes depending upon whether surface is freshly cut or
has been exposed. Both sap and heart wood change colour due to
slight oxidation by exposure. The colour may vary from creamy
white to jet black through varying shades of grey, yellow, pink,
red, brown and purple.
Adarker colour in wood indicates greater durability.
odour
Most woods do not have any characteristic odour to distinguish
them from others. Odour also appears only when freshly cut and
disappears upon exposure.

14. Hardness/Resistance
It is defined as the resistance of the material to indentation or
penetration by a foreign body. The timber readily indented by
finger nail is termed as soft to very soft timber.
The timber not readily indented by finger nail but readily cut
with knife is termed as moderately hard.
The timber not indented by finger nail and cut with difficulty
by knife is termed as hard to very hard.
Lusture
It is due to the difference in the light reflecting property of the
different cells.

15. Density
Density of wood is great significant feature to use as timber. It is
commercially significant because it affects the cost of Transport. It
is expressed as weight per unit volume. The density varies
considerably in different timbers. Based on density it is classified
under three categories.
• Light to very Light → Below 550 Kg/m3
• Moderately Heavy → 550-750 Kg/m3
• Heavy to very Heavy →Above 750 Kg/m3
(The above classification is determined at a specified moisture content of 12%)
3.1.6 density group: Timber with a density exceeding 480
kg/m3 is classified under density group D1, and timber
with a density between 400 kg/m3 and 480 kg/m3 under
density group D2.

16. Grain
Refers to general direction /Alignment of wood cells.
Depending on the actual alignment grain may be straight, spiral,
interlocked, wavy or irregular.
Nature of grain considerably affects the strength, seasoning and other
properties of timber.
If grain is not straight then it is a defect in timber.
Spiral grain is a natural defect due to the irregularities in the formation
of the fibers. This makes the conversion difficult and also reduces
the strength of the timber.
Interlocked grain is the one which changes direction to left and
right more or regularly. Wavy grain is produced by undulations and
this weakens the timber many times.

17. Texture
It is due to the size of cells distribution and propagation of
various types of cells.
This should not be confused with grain which only refers to the
alignment.
Based on texture timber is classified as Fine, Medium coarse
and Coarse.
Majority of woods are even textured and some have uneven
texture due to difference in size and distribution.
The feeling that felt due to the touch of the wood is called as
texture and coarse textured woods will be rough on the surface
and fine textured wood is smooth on the surface.

18. Construction Materials
• The type of material you use on a project will
depend on the type, size and nature of your
project.
• As far as small woodworking projects go here
are some common materials for their
construction.

19. Selecting Wood
• There are two main types of
wood we use for wood
projects;
• hardwood and softwood.
• The actual hardness or
softness of the wood has
more to do with the type of
tree it comes from than the
actual strength of the wood.

20. Hardwoods
• Hardwood come from
deciduous trees. These
are trees that lose their
leaves in the winter. They
come in a wider variety of
colours and textures than
softwoods. These woods
are typically the choice of
woodworkers for
furniture, cabinetery and
flooring projects.

21. Softwoods
• These woods come
from coniferous or
evergreen trees.
These woods are
primarily used for
construction purposes
(homes, sheds, barns
etc.). These types of
wood are abundant in
North America.

22. Softwoods cont’d
• Softwoods use for general
construction are usually
Spruce (s) , Pine (p) or Fir
(f) trees. Construction
lumber is labelled as SPF
and can be any of these
three types of lumber.
Softwoods are also
used in the manufacture
of fiberboard and paper.

23. Where do woods come from?
Temperate regions (softwoods)

24. Where do woods come from?
Tropical regions (soft & hardwoods)

25. What is Timber Framing?
Timber Framing also called post and beam, is as the name
suggests a method of timber construction that relies on the
timber frame as the primary structural support for the building.
Timber Framing is a centuries old
construction method of creating
timber framed structures jointed
together with wooden pegged
mortises and tension joints.
People throughout the world have been living in timber framed
structures for thousands of years. This has been for many reasons,
the ready supply of wood for timber frames, the ease of
construction, the durability of the material and of course its
aesthetic appeal