Timber civil engineering material - asst. proff. pramesh hada

CIVIL ENGINEERING MATERIAL
CHAPTER 7.0 TIMBER
(IMP FOR 7 – 15 MARKS)
Prepared By:
Er. Pramesh Hada
MSC in Urban Planning
B.E In Civil (Asst. Professor),
Civil Engineering Dept.
Nepal Engineering College

TIMBER
Timber : Sources, Types, Classification,
Characteristics, Advantages & Uses.
Growth & Structure of Exogenous Plants
Defects in Timber (pu )
Characteristics of Common Timber trees
Seasoning of Timber :Air, Water, Kiln, Chemical,
Electrical & Boiling (pu)
Er.PrameshHada,Asst.Professor,civil
EngineeringDepartment,nec
Electrical & Boiling (pu)
Preservation of Timber
Properties and Uses of Bamboo
Wood Based Products – Veneer, Plywood, Boards,
Laminated Boards etc.

TIMBER
•Is one of the important construction materials.
•Used as structural elements in buildings, widely for
doors, windows and partitions and find large use through
secondary wood products like plywood, particle boards
and laminated boards, etc.
•Wood Which is useful for engineering or Other
structural Purpose is called “Timber”
•Mostly uses timber – plywood,Posts et. in Formwork in
•Mostly uses timber – plywood,Posts et. in Formwork in
RCC,RBC etc.
•Both hard as well as soft woods are in use.

• When tree has been cut down and its stem and branches are
roughly converted into pieces of suitable length, then it is
known as Rough Timber.
• When roughly converted timber is further sawn and
converted into commercialized the planks,battens, posts etc is
called converted Timber.
(Planks – board,plyboard,woodboards),
(battens-Partition, Roofing, something to hold)
Mostly Timber used in load bearing
TIMBER
Mostly Timber used in load bearing
structure is called structural timber

PROPERTIES OF TIMBER/WOOD
Physical Properties :
1. Density
- light — very light: density less than 550 kg/m3, eg.
bamboo
- moderately heavy: density 550 kg/m3 — 750 kg/m3, eg.
deodar
- heavy-very heavy: density greater than 750 kg/m3, eg. Sal
2. Bulk Density - Defined as the mass of many particles of the material
divided by the total volume they occupy.
- Depends on air voids present in wood.
divided by the total volume they occupy.
- Depends on air voids present in wood.
3. Moisture Movement
- Wood is liable to shrink or swell with the movement of
moisture. (increase or decrease)
4. Shrinkage :
- Is a Reduction in linear and volumetric dimension due to
drying of moisture.

5. Swelling (Increase in size)
- It is increase in linear and volumetric dimension on
absorbing moisture.
6. Sound conductivity
- Has high Sound Conductivity
- Sound velocity in wood is greater than others.
PROPERTIES OF TIMBER/WOOD
7. Thermal Conductivity
- Has very low thermal conductivity.
- so uses for maintain heat temperature in rooms.

MECHANICAL AND THERMAL PROPERTIES OF
TIMBER/WOOD:
As wood is natural material there is different
mechanical properties for different wood
Mechanical properties are governed by soil type,
climate and other factors.
Properties affected by specific gravity, moisture
content, knots and other defects.
Wood can’t resist fire and burnt easily.
Wood can’t resist fire and burnt easily.
It will be better to take precautions to save timber
structure from thermal action

CHARACTERISTICS OF GOOD TIMBER (PU 2010)
Uniform color, strong, durable and workable
Straight and compacted fibers
Fresh cut surface : sweet smelling
Struck: clear ringing sound
Relatively heavier
Free from all types of defects and disease of timber like
knots.
knots.
Planning surface: bright appearance with silky.
Sawing: Cut with a saw - not clogging (clogging -Become
or cause to become obstructed)
Firm adhesion of fibers and compacted medullary rays
Well seasoned

Fibers in timber
Defects of Timber
Sawing

ADVANTAGES OF TIMBER: (PU 2011)
availability: source and transportation
strength: light weight and higher strength
easy to handle and planed easily
joining: simple
Repair and Modification: Easy
superior, thermal insulation, sound and electrical resistive
uses: furniture and decorative purpose
uses: furniture and decorative purpose
strong and flexible
corrosion resistance: excellent
higher shock and impact strength .
Quick and easy to build.
Cheaper than other types of building materials.
Easy to heat and cool depending on the weather.
More eco-friendly than other materials
Can last many years if proper maintenance is carried out.

USES OF TIMBER
It is mainly used for following categories of works
(i) It is used for construction purposes including building
construction, houseposts, beams, rafters, bridges, piles,
poles etc.
(ii) It is used for furniture and cabinet making.
(iii) Used for door and window frames.
iv) Uses for Formwork, scaffolding etc,
iv) It is also used for heavy packing cases such as
iv) It is also used for heavy packing cases such as
machinery and similar stores.
(v) It is used for manufacturing agricultural implements
and tool handles.
(vii) It is used for manufacturing veneers, plywoods,
boards etc.

HOUSEPOSTS
SCAFFOLDING

DISADVANTAGES OF TIMBER: (PU2011)
Defects in timber can reduce the life of wood.
Affected by relative humidity, fungi, insects.
Modification of general arrangement drawings if based
on masonry construction
Transportation and carriage access
Exposure to weather before enclosed
Exposure to weather before enclosed
vulnerability to decay of timber when exposed to
excessive moisture.
If left untreated, timber become water logged and
crack or chip.
Timber is more susceptible to fire than other building
materials unless treated and maintained.

Wood is a product obtained from the tree.
In simple classification of tree, it can be classified as:
1. Standing timber - if a tree is living then the timber is
termed as Standing Timber.
2. Rough timber - if a tree is fallen then the timber is
termed as Rough timber.
3. Converted timber - If a tree is modified into desired
TYPES OF TIMBER/WOOD
3. Converted timber - If a tree is modified into desired
size and shape then the timber is termed as Converted
timber.
on the basis of mode of growth , the types of trees are :
1. Endogenous Tree
2. Exogenous Tree

1. ENDOGENOUS TREE
Trees grow in inward direction with the addition of fibrous (like
of jute) layer at tip portion, i.e the growth is longitudinal.
Trees are hollow at the core and have flexible stem.
e.g- Bambo, coconut, Sugarcane etc.
For construction purpose only bamboo can be used.
Are very flexible due to which they are not generally used for
construction material.
2. EXOGENOUS TREE
Trees increase in bulk by growing outwards and distinct
consecutive rings are formed in the horizontal section of such
consecutive rings are formed in the horizontal section of such
trees.
These rings are called annual rings, because one such ring added
every year, such trees grow bigger in diameter as well.
Life of trees can be find by counting the annual rings.
e.g – Sisham, Sal, Pine etc.
Timber from these suitable for construction purpose
These are further classified as
1. Deciduous tree 2. Coniferous tree

EXOGENOUS TREE
Deciduous tree
Are characterized by flat and broad
leaves which fall in autumn season and
new one appear in spring season
Hard wood is obtained by such tree
which can be used for superior structural
and engineering work.
e.g – Sal, Sisham, Teak etc.
Coniferous tree
Coniferous tree
Trees are characterized by needle
shaped thin leaves which are evergreen
Trees bear conical shaped fruits and
yield resins ( viscous substance )
Soft variety of woods are obtained
Used is general constructional purpose
- e. g Pine, deodar etc.

DIFFERENCE BETWEEN HARD WOOD AND SOFT
WOOD (CHARACTERISTICS)
Aspects hard wood soft wood
Annual rings Indistinct Clearly distinct
Medullary rays Distinct indistinct
Color Dark Light
Strength Strong: tens, comp, shear Strong: direct pull
Weak: shear
Structure Non resinous Resinous and split easily
Structure Non resinous Resinous and split easily
Weight Heavy Light
Uses Structural purpose Aesthetic and light structural
purpose
Sources Deciduous Conifers/evergreen trees
Branches Less branches More branches
Example Sal, teak, deodar, shisam Pine, chir, kail etc

SISHAM TREES

SAL TREE

TEAK WOOD

PINE TREES

DEODAR TREES

GROWTH OF A TREE
Roots of the tree suck a solution of salts from the soil in
spring season.
Salts are food for the tree and roots transmit the same
through the trunk of tree to its branches and leaves.
Solution of salts looses some of the moisture because of
evaporation and absorbs carbon dioxide from the air. This
action in the presence of sun makes the solution a bit
viscous. This transformed viscous solution is known as sap.
viscous. This transformed viscous solution is known as sap.
Viscous sap descends below the bark and leaves a thick layer
in autumn. Layer of sap left below the bark gets transformed
to wood and is known as cambium layer. A fresh layer is
thus added on the outside of the tree every year forming a
new annual ring. The new ring represents a year’s growth of
tree.
Medullary rays carry the sap from below the bark to the
interior thereby nourishing the tree.

STRUCTURE OF A EXOGENEOUS TREE (PU 2009,2010)
• Pith/Medulla/Core
•Heart wood
•Sap wood
•Cambium Layer
•Inner Bark
•Outer Bark
•Medullary rays

Pith/ medulla/core:
It is first formed portion of trees.
It consist entirely cellular tissues and nourishes the plant in young
age.
It is found as dead part of the trees incase of matured trees and
decayed.
Annual rings:
Grows extra layer around the circumference of the trees per year
Circular concentric rings
STRUCTURE OF A EXOGENEOUS TREE
Circular concentric rings
Each rings indicates the age of tree in year
Heart wood:
Annual rings around the pith at the innermost central portion of the
tree section
Strong, durable and compact part of trees
Darker in color
Best part of trees in engineering views
Imparts rigidity to the trees
Doesn’t take active part in growth of trees

Sap wood:
Outer annual rings between heart wood and the cambium layer
Light in color and weight as well
Indicates recent growth and contains sap
(Sap = A watery solution of sugars, salts, and minerals that circulates through the vascular
system of a plant )
Annual rings of sap wood are less sharply defined in comparison to heart wood
Takes active part in growth of trees
Cambium layer:
Thin layer of sap between sap wood and inner bark
It indicates sap which has yet not been converted into sap wood
STRUCTURE OF A EXOGENEOUS TREE
It indicates sap which has yet not been converted into sap wood
If barks are removed and get exposed, the cell cease and death
Inner bark:
Inner layer covering the cambium layer
Protect cambium layer from any injury
Outer bark:
A protective layer, outer skin covering the trees
Contains cracks and fissures sometimes
Consists of cells of wood fibers and is known as cortex
Medullary rays: (Pit rays )
Radial fibers extending from pith to cambium layer
Hold the annual rings of heart wood and sap wood together

MICROSTRUCTURE OF WOOD
Structure of wood apparent only at great magnifications is called
microstructure.
If study through microscope, it becomes evident that wood consists
of living and dead cell of various shape and sizes
Living cell consists
Membrane (consists cellular tissue and cellulose)
Protoplasm (granular and transparent, viscous vegetables,
protein composed of carbon, hydrogen, oxygen, nitrogen and
sulphur)
sulphur)
Sap (differ from protoplasm by presence of phosphorous and
shape is oval)
Types of cell on the basis of their function:
conductive cells
mechanical cells
storage cells

Conductive cells: serves to transmit nutrients from
roots to the branches and leaves
Mechanical Cells: these cells are elongated, thick
walled and having tightly interconnected narrow interior
cavities
- imparts strength to the wood
Storage Cell: serves to store and transmit nutrients to
MICROSTRUCTURE OF WOOD
Storage Cell: serves to store and transmit nutrients to
the living cells in horizontal direction and they are
usually located in the medullary rays

Resinous wood

DEFECTS IN TIMBER (PU 08,09,10,12,13)
Defects are either due to growing phases of tree or defect
occurring after cutting trees
Defects reduce the usefulness of wood as aesthetic
appearance as well as strength
1. Heart Shake
- This defect usually occurs in over matured trees due to
shrinkage of heart wood
- These cracks are mostly confined to heart wood portion
and diminishing towards outward.
and diminishing towards outward.

2. Star Shake
- It is confined in the outward portion
and diminishing towards center.
- It occurs due to frost action and strong
heat of sun.
- It is the most serious defect because it
tends to separate single log into small
pieces.
DEFECTS IN TIMBER
3. Radial Shake
- These are radial cracks extending from
centre towards bark .
- These are similar to star shake but are
irregular and numerous.
- It occurs due to drying of sap or
moisture .

4. Cup or Ring Shake
- Is the separation of tissue along annual
rings
- If the shake is whole round the annual
ring then it is called ring shake and if it is
half way round the ring then it is called cup
shake.
- It is due to unequal seasoning and change
in humidity.
DEFECTS IN TIMBER
5. Rind Gall
- Is the curved irregular swelling on surface.
- Due to development of new sap layer on
wound left after branches have been
irregularly cut.
- New layer fails to unite with old one and
decay starts from that point

6. Knots
- This defect occurs due to formation of annual rings at right
angles to surface and also due to twisting of fibers.
- The roots of the branches yet embedded(Enclosed firmly) by the
tissue and knots are formed
- Knots reduce the aesthetic value and effects tensile strength
- Knots may be round or oval shaped
DEFECTS IN TIMBER

7. Twisted fibers
- This defect occurs due to wind velocity constantly turning trees in
one direction only.
DEFECTS IN TIMBER
8. End Splits
- Occurs only at the ends of log due to exposed conditions during
seasoning.
- May be prevented by painting the ends of log or covering with
metallic cap.

9. Druxiness and Foxiness
(Druxiness is a term that is defined as a disease that is
found in timber or wood. It is caused or brought about by
a wound located in the layer known as the cambium
which is attacked by fungus.)
(Foxiness is caused due to poor ventilation during storage
or due to over maturity of the tree).
DEFECTS IN TIMBER
- These are stains or patches on the surface of timber
which destroy the appearance and may cause decay of
timber
- Stain may be in form of white patches or mottled
reddish colour.
(stains - A soiled or discolored appearance)

SEASONING OF TIMBER: (PU 09,10,11)
Wood is hygroscopic material, dry wood absorbs moisture from
surroundings
Freshly cut wood may contains more than 50% water in the
form of sap and moisture
After removal of such water from wood then it can be used in
diff. engineering works
Thus drying process of timber is known as seasoning of timber
Moisture must be extracted during seasoning under controlled
conditions as nearly as possible at a uniform rate from all parts
conditions as nearly as possible at a uniform rate from all parts
of the timber
If the drying is irregular, the shrinkage of timber will also be
irregular and it will set up internal stresses between the fibers
Moisture content in wood may be:
Free moisture: present in cell cavities (major part)
Bound moisture: present in cell wall ( associated with the body of
timber)
o Free moisture/ water evaporated first and the point at which cell
cavities no longer contain free water is known as fiber saturation point.

FOLLOWING ARE THE DIFFERENT OBJECTIVES OF
SEASONING:
Timber to burn readily, if used as fuel
Decreased the weight of timber: easy handling and
low cost
Impart hardness, stiffness, strength, better electrical
resistance. (stiffness - hard to bend)
To increase resisting power of timber against the
cause of defects
cause of defects
To maintain the shape and size of the component of
the timber
To make it fit for painting and other treatment
For effectively gluing and joining
To reduce the shrinkage, warping, twisting
(shrinkage - becoming less or smaller)
(Warping - Bend out of shape, as under pressure or from heat)

METHODS OF SEASONING OF TIMBER:
Natural seasoning
Air seasoning/ drying
Water seasoning
Artificial seasoning
Air seasoning:
Method used with the timber stacked in the open air. It
requires the following:
Stacked stable and safely with horizontal spacing of at
Stacked stable and safely with horizontal spacing of at
least 25 mm.
Ends of boards sealed by using a suitable sealer or cover
to prevent too rapid drying out via the end grain.
The stack raised well clear of the ground, vegetation, etc
to provide good air circulation and free from rising damp,
frost, etc.
Over head cover from effects of direct sunlight and
driving weather.

AIR SEASONING:
This method is economical one
Takes 2 to 4 years
Covers more space
No need of skilled labor
Suitable for cut of sawn planks pieces of wood not for log
of wood
Timber can stack either horizontally or vertically
Timber can stack either horizontally or vertically

AIR SEASONING:

WATER SEASONING
Log of wood is kept completely immerged in stream of
water
Sap, sugar etc are leached out of wood and replaced by
water
Then log is kept out of water after 2 to 4 weeks and
placed in air
Quick process and also remove organic matters/
Quick process and also remove organic matters/
materials
Elasticity may reduced and make timber brittle
Boiling of timber in water is another rather quick
process
Takes long time to be dried but less than air seasoning

ARTIFICIAL SEASONING:
This is quick process of seasoning and moisture content
can be controlled.
o Popular method of artificial seasoning is KILN
SEASONING.
Reason for carrying artificial seasoning are :
Shrinkage, cracking and warping are minimized
Drying is controlled and no chances for the attack of
fungi and insects
Drying surface is even and uniform
Reduced duration of seasoning
Desired moisture content can be attainable
(shrinkage – becoming less or smaller)
(warping - Bend out of shape, as under pressure or from heat)

KILN SEASONING:
This process consists basically of introducing heat.
May be directly, using natural gas and/or electricity or
indirectly, through steam-heated heat exchangers,
although solar energy is also possible.
In the process, deliberate control of temperature,
relative humidity and air circulation is provided to give
conditions at various stages (moisture contents or
times) of drying the timber to achieve effective drying.
times) of drying the timber to achieve effective drying.
Timber is stacked in chambers, called wood drying
kilns, which are fitted with equipment for manipulation
and control of the temperature and the relative
humidity of the drying air and its circulation rate
through the timber stack.
Provides a means of overcoming the limitations imposed
by erratic(inconsistent) weather conditions.
Almost all commercial timbers of the world are dried in
industrial kilns.

Advantages of conventional kiln drying include higher
throughput and better control of the final moisture content.
Conventional kiln and solar drying both enable wood to be
dried to any moisture content regardless of weather
conditions.
For most large-scale drying operations solar and
conventional kiln drying are more efficient than air drying.
Compartment-type kilns are most commonly used in timber
companies.
KILN SEASONING:
companies.
A compartment kiln is filled with a static batch of timber
through which air is circulated. In these types of kiln, the
timber remains stationary. Drying conditions are
successively varied from time to time in such a way that the
kilns provide control over the entire charge of timber being
dried.
Method is well suited to the needs of timber companies,
which have to dry timbers of varied species and thickness.

Kilns are used because the process speeds up seasoning and it
can be used to accurately control the moisture content of the
wood.
Wood is carefully stacked inside the brick kiln.
Water is heated and the resulting steam allowed to enter the
kiln, circulating inside and around the wood boards. Over
time, the amount of steam (humidity) is reduced until the
wood has the desired moisture content.

Compartmental kiln
A compartment kiln is a single enclosed container or
building, etc.
Timber is stacked as described above and the whole
stack is seasoned using a program of settings until the
whole stack is reduced to the moisture content
required.
Progressive:
Progressive:
A progressive kiln has the stack on trolleys that
‘progressively’ travel through chambers that change
the conditions as it travels through the varying
atmospheres. (trolleys - An wheeled vehicle that runs on rails and is
propelled by electricity)
The advantage of this system, although much larger,
has a continuous flow of seasoned timber coming off
line.

Solar kiln
A solar kiln is a cross between kiln drying and air drying.
These kilns are generally a greenhouse with a high-
temperature fan and either vents or a condensing system.
Solar kilns are slower and variable due to the weather, but
are low cost.
Other seasoning of Timber are
Boiling or Steam seasoning
Submersion in boiling water or the application of steam
speed the drying of wood. This method is said to cause less
shrinkage "...but it is expensive to use, and reduces the
shrinkage "...but it is expensive to use, and reduces the
strength and elasticity of the timber."
Chemical or salt seasoning
Salt seasoning is the submersion of wood in a solution of
urea, sodium nitrate or sodium chloride, all of which act as
dehydrating agents. Then the wood is air dried.
Electrical seasoning
Electrical seasoning involves running an electrical current
through the timber causing heat to build up drying the wood.
This method is expensive but is fast and uniform quality.

PRESERVATION OF TIMBER:
To prevent the probable defects of timber due to fungi, insects,
alternate heating and cooling timber must be preserved in order to
increase the life span of timber, make durable.
Following are the various methods of preservation :
Charring:
Very old method, no preservatives are used
Surface to be charred is kept wet for about half an hour and
burnt up to 15mm depth over a wood fire
The charred portion is then cooled by water
The charred portion is then cooled by water
This burnt layer doesn’t affected by moisture, fungi etc
Adopted for lower ends of posts for fencing, telephone etc
(Charring: Burn to charcoal )

Tarring : (coating)
•Timber surface is coated with hot coal tar with brushes
•Coal tar has unpleasant smell and appearance
•Coal tar makes timber unsuitable for painting
•Adopted for frames of doors and windows, rough timber work
etc
•Coal tar is fire-resistant.
( Tar - It can be produced from coal, wood, petroleum. It is black,
and a mixture of hydrocarbons and free carbon. )

Painting:
Paints are good preservatives
Form thin layer in the surface of timber
Thin surface acts as barrier for defective environmental factors
Creosoting:
Timber surface coated with creosote oil
Creosote oil is obtained by distillation of tar (distillation - process of
purifying a liquid by boiling it and condensing its vapors)
Steps are:
Timber are thoroughly seasoned and dried
Timber are thoroughly seasoned and dried
Placed well seasoned wood in air tight chamber
Air is pumped out from chamber
Creosote oil is then pumped under high pressure of 0.7-1.0N/mm2 and
temperature of about 500C
After 1 to 2 hrs, when timber has sufficiently absorbed creosote oil, it
is taken out of chamber
Creosote oil is antiseptic or it is poisonous to the wood-attacking fungi
Creosote oil: black or brown liquid and weakly affected by water
Unpleasant odour and having low wood-penetrating ability to the
extent of 1mm to 2mm only
It produces undesirable color in timber

Abel’s process:
Timber surface is cleaned and coated with a dilute
solution of sodium silicate
Paste of slaked lime is then applied and finally, a
concentrated solution of silica soda is applied on the
timber surface
This process is quite satisfactory in making the
This process is quite satisfactory in making the
timber fire- resistant
Fire proofing of timber:
Timber can’t be made fire proof but some chemical
treatment may reduce the fire attack towards the
timber
Soaking of timber in ammonium sulphate,
ammonium chloride, zinc chloride etc improves the
fire resisting capacity of timber.

BAMBOO – (PROPERTIES AND USES)
Bamboo, like true wood, is a natural composite material with
a high strength-to-weight ratio useful for structures.
In China and India, bamboo was used to hold up simple
suspension bridges, either by making cables of split bamboo or
twisting of sufficiently pliable(workable) bamboo together.
Bamboo has also long been used as scaffolding; the practice
has been banned in China for buildings over six storeys, but is
still in continuous use for skyscrapers in Hong Kong.
still in continuous use for skyscrapers in Hong Kong.
In Japanese architecture, bamboo is used primarily as a
supplemental and/or decorative element in buildings such as
fencing, fountains, grates and gutters, largely due to the
ready abundance of quality timber.
Notes (Grates - A barrier that has parallel or crossed bars
blocking a passage but admitting air.)
(Gutters - A channel along the eaves or on the roof; collects
and carries away rainwater )

Can be cut and laminated into sheets and planks(like
board,plyboard).
Bamboo intended for use in construction should be
treated to resist insects and rot. The most common
solution for this purpose is a mixture of borax and boric
acid.
Bamboo has been used as reinforcement for concrete in
Bamboo has been used as reinforcement for concrete in
those areas where it is plentiful, though dispute exists
over its effectiveness in the various studies done on the
subject.
Bamboo does have the necessary strength to fulfil this
function, but untreated bamboo will swell with water
absorbed from the concrete, causing it to crack. Several
procedures must be followed to overcome this
shortcoming.

Bamboo was treated with borax and boric acid as a fire retardant
and insecticide and bent in the required shape.
The bamboo sections were joined with reinforcement bars and
concrete mortar to achieve the necessary lengths

WOOD BASED PRODUCTS
1. Veneers
Veneering is the primary process of manufacturing
woods.
Prepared by slicing and sawing of wood in thin sheets of
0.4mm to 6mm.
Are of superior Quality.
Used in manufacturing ply woods, battens, lamin
Used in manufacturing ply woods, battens, lamin
boards.

2. Plywood
Is a manufactured wood panel from the family of
manufactured boards (such as medium-density
fibreboard (MDF), particle board (chipboard), etc.) made
from thin sheets of wood veneer.
Prepared by gluing together odd number of veneers with
grain direction of core block at right angle to adjacent
veneer or ply.
WOOD BASED PRODUCTS
veneer or ply.
Are used in making partition, furniture, ceiling, doors,
paneling wall, Formworks for concrete.

PLYWOOD

3. BATTEN BOARD
Is a solid block with core of sawn thin wood
The Thickness of core is about 20mm to 25mm
Total thickness of board is about 50mm
Is Light and strong
Do not crack or split easily
Uses: partition wall, furniture, shutters, packing case
Uses: partition wall, furniture, shutters, packing case

4. LAMIN BOARD
Consist of core of strips each not exceeding 7 mm in
thickness.
These strips are joined together with two face veneers.
Lamin board are used for furniture, partition, doors,
windows, ceilings,etc.

IMPREG TIMBER /IMPREGNATED TIMBER
Timber which has been made flame-resistant, fungi-
resistant, or insect-proof by forcing into it under
vacuum or pressure a flame retardant or a fungal or
insect poison.

COMPREG TIMBER
Processed wood whose cells are impregnated with a resin and
compressed, to reduce shrinking and swelling and to
increase density and strength.
Compreg is a very special wood composite material with
exquisite mechanical properties.
Compreg indicates that it is both impregnated and
compressed.
Used in applications where long durability, hardness, and
dimensional stability is required e.g. gears, rolls and wear
dimensional stability is required e.g. gears, rolls and wear
strips of industrial conveyors, woodworking machine tables.
Regardless of its hardness, it is comparatively easy to
machine, which makes it an excellent choice for
manufacturers of exclusive woodworking products.

Timber civil engineering material - asst. proff. pramesh hada

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