USE OF WOOD IN VERNACULAR ARCHITECTURE.

1. VERNACULAR MATERIAL
TIMBER
PRESENTED BY :-
SHAGUN DHIMAN
AR/09/523
COLLEGE OF ARCHITECTURE
I.E.T BHADDAL, ROPAR

2. Vernacular Architecture
Vernacular architecture is the informal, functional architecture of structures, often in
rural areas , built of local materials and designed to meet the needs of the local people.
 Vernacular architecture tend to evolve over time to reflect the environmental,
cultural and historical context in which it exists.
 The builders of these structures are unschooled in formal architectural design and their
work reflects the rich diversity of India's climate, locally available building materials, and
the intricate variations in local social customs and craftsmanship.
Timber
The word timber is derived from an old English word “timbrian” which means to
built. The timber thus denotes wood which is suitable for building or carpentry or various
other engineering purposes and it is applied to the trees measuring not less than 600 mm
in girth or circumference of the trunk.
TYPES OF WOOD
All native species of trees are divided into two classes.
– Hard wood have broad leaves and are deciduous. They shed their leaves at the end
of each growing season.
– Soft woods are conifers which have needle like or scale like leaves. Softwood except
cypress, larch and some exotic species are evergreen.

3. SEASONING OF TIMBER
Seasoning is the controlled process of reducing the moisture content (MC) of the
timber so that it is suitable for the environment and intended use. We need to
reduce the MC of timber for the following reasons…
Seasoned timber although lighter will be stronger and more reliable.
The sap in timber is a food for fungi and wood parasites. Remove the sap and
the wood will be less attractive to these dangers.
For construction grade timber the timber must be below 20% MC to reduce the
chances of Dry Rot and other fungi infestations.
Dry well seasoned timber is stronger.
Dry well seasoned timber is easier to work with and consequently safer especially
machine working.
Timber with higher moisture content is difficult to finish i.e. paint, varnish, etc.
There are two main ways of seasoning timber, Natural (Air) and Artificial (Kiln)
drying. Both methods require the timber be stacked and separated to allow the
full circulation flow of air, etc. around the stack.

4. Air Seasoning:-
Air seasoning is the method used with the timber stacked in the open air. It requires the
following:
 Stacked stable and safely with horizontal spacing of at least 25 mm.
 Vertical spacing achieved by using timber battens (piling sticks) of the same or neutral
species. Today some timber yards are using plastics. The piling sticks should be vertically
aligned and spaced close enough to prevent bowing say 600 to 1200 mm max centres.
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.
The details depend on the size, quantity and species of the timber. You cannot however
expect to obtain less than 16 - 17% mc in the UK. Further seasoning needs to be done
inside, in heated and ventilated buildings.

5. Kiln Seasoning:-
There are two main methods used in artificial seasoning, compartmental, and
progressive. Both methods rely on the controlled environment to dry out the timber and
require the following factors:
Forced air circulation by using large fans, blowers, etc.
Heat of some form provided by piped steam.
Humidity control provided by steam jets.
The amount and duration of air, heat and humidity again depends on species, size,
quantity, etc. Schedules are published for the various species to enable operators to select
an appropriate drying environment. In the UK they are usually provided by the Kiln
Manufacturers and also published in the Handbook of Hardwoods and Handbook of
Softwoods (BRE).

6. Properties Of Timber
 Strength:- The timber should be strong enough to with stand the loads
weather being applied slowly or suddenly. It should posses enough strength in
direct compression and transverse direction.
 Durability:- A good timber should be capable of resisting the various actions
due to fungi, insects, chemicals, physical and mechanical agencies.
Weather Resistance:- A good timber should possess adequate resistance
against weathering effects such as alternate dry and wetting, alternate heating and
cooling because of temperature variations, wind effects.
 Fire resistance:- The timber should offer sufficient resistance against fire so
that it does not easily ignite it helps in fire protection of buildings.
 Elasticity:- The timber should be capable of regain its original shape when
load causing deformation is removed. The property is important when timber is to
be used for bows carries shafts, sport goods, wooden beams, wooden floor , etc.

7. Work Ability:- The timber should be easily workable and should not clog
the teeth of saw. It should also be capable of being easily planned or made
smooth.
 Toughness & Abrasion:- A good timber should capable of offering
resistance to shocks due to vibration and should not deteriorate due to
mechanical wear.
Other properties:-
Timber should have sufficient weight. A timber with heavy weight is consider
to be sound and strong.
The structure of timber should be uniform, hard and compact.
A timber should have sufficient hardness.
A timber should have favorable physical characteristics such as a dark colour,
shining appreance, free from defects, sweet smell, good sound when struck, etc.

8. Availability of various timber species
Timber is a very useful material. which is available in huge Quantity in all over the
India.
 Every tree has its own growth requirement.
Thus according to the regions climate various species of trees are available in
difference states.
Various timbers used for different purposes due to their more local
availability are given below…..
Tree name Colour Density Location Chara-feature,uses
Arjun Dark brown 870 kg/m³ Central India It is heavy and strong. It has uses
as beams, rafters, and posts.
bamboo - -
Throughout India,
especially Assam and
Bengal
Not actually a tree, but a woody grass,
it is flexible, very strong and durable. It
is used for scaffoldings, thatched
roofs, rafters, temporary bridges, and
so forth.

9. Tree
name
Colour Density Location Chara-feature,uses
Babul Whitish red 835 kg/m³
Andhra Pradesh,
Maharashtra, Madhya
Pradesh, Tamil Nadu,
Karnataka, Bengal,Gujarat,
Uttar Pradesh
It is strong, hard and tough and it takes up
a good polish. It is used for such products
as bodies and wheels of bullock cart,
agricultural instruments, tool handles, and
well curbs.
Deodar Yellowish brown 560 kg/m³
Himalayas, Punjab, Uttar
Pradesh
Deodar is the most important timber tree
providing soft wood. It can be easily
worked and it is moderately strong. It
possesses distinct annual rings. It is used
for making cheap furniture, railway
carriages, railway sleepers, packing
boxes, structural work and so forth.
Jack
Yellow, darkens with
age
595 kg/m³
Karnataka, Maharashtra,
Tamil Nadu, Kerala
It is moderately strong and easy to work. It
takes a good finish and maintains its
shape well. It has many uses including
plain furniture, boat construction, well
curbs, door panels, cabinet making and
musical instruments.
Mango Deep gray 560-720 kg/m³ Throughout India
The mango tree is well known for its fruits.
It is easy to work and it maintains its shape
well. It is moderately strong. It is most
often used for cheap furniture, toys,
packing boxes, cabinet work, panels for
doors and for windows.

10. Tree
name
Colour Density Location Characteristic features & uses
Mulberry Brown 650 kg/m³ Punjab
It is strong, tough and elastic. It takes up a clean finish. It can be
well seasoned. It is turned and carved easily.
Oak
Yellowish
brown
865 kg/m³
Oak is strong and durable, with straight silvery grain. It is used for
preparing sporting goods.
Palm Dark brown 1040 kg/m³ Throughout India
It contains ripe wood in the outer crust. The colour of this ripened
wood is dark brown. It is strong, durable and fibrous. Palm is
used for furniture, roof covering, rafters and joists.
Pine
Pine wood is hard and tough except white pine which is soft. It
decays easily if it comes into contact with soil. It is heavy and
coarse grained. It is used for pattern making, frames for doors
and windows, and for paving material.
Red cedar Red 480 kg/m³ Assam, Nagpur
It is soft and even grained. It is used for furniture, door panels
and well curbs.
Sal Brown[1]
880-1050
kg/m³[14]
Karnataka,
Andhra Pradesh,
Maharashtra,
Uttar Pradesh,
Bihar, Madhya
Pradesh, Orissa
It is hard, fibrous and close-grained. It does not take up a good
polish. It requires slow and careful seasoning. It is durable under
groung and water. It is used for railway sleepers, shipbuilding,
and bridges.

11. USE OF TIMBER IN CONSTRUCTION
Timber is a modified material of wood. It is basically used in construction in
following forms…..
 Roofing
 Walls
 Flooring
 Trusses
 Cladding
 Doors & Windows Frames & Shutters.
 Formwork , Centering & Scaffolding
 Staircase.

12. ROOFING:-
 In roofing basically timber is used in making Pitched roofs or Sloping roofs.
 These roofs are those which have the decks or surfaces with considerable slope for
covering the building structure.
 This roof is lighter then flat roofs and constructed either in wood and steel.
 Such Roofs are most suited in regions of heavy rainfall and snowfall.
These are classified in three categories:-
1. Single Roofs
2. Double or Purlin Roofs and
3. Triple- membered or framed or trussed roofs.

13. 1. Single roof:-
These roofs consist only of common rafters which are secured at the ridge and wall
plates. This roof is in following types…..
i. Lean-to-roof or shed or verandah roof,
ii. Couple roof,
iii. Couple close roof,
iv. Collar beam roof or Collar Tie beam roof.
a. Lean-To-Roof:-
1) This consist of simplest form of pitched roof covers the verandah of a building
and projects from the main wall of the building.
2) This consist of common rafters usually inclined at 30˚ against wall.
3) The lower ends or feet of the common rafters are notched and nailed to a wooden
post-plate jointed.
4) This roof is generally used for sheds, verandahs etc.

14. b. Couple Roof:-
1) In this type of roof, each couple or pair of common rafters is made to slope
upwards from the opposite walls.
2) They are supported at the upper ends at the ridge piece or ridge board in the
middle.
3) This roof is therefore, only adopted for a maximum span of 3.5 meters.
c. Couple-close Roof:-
1) This is similar to couple roof except that the legs of common rafter are closed
by a horizontal tie known as tie beam.
2) The connection between the tie and the feet of rafters is usually obtained by
means of dovetail joint.
3) This type of roof can be used for a maximum span of 4.5 mt.

15. d. Collar beam Roof:-
1) This is similar to the couple-close roof, except that the horizontal tie is now
raised up from feet of the rafters to almost middle of the rafters, which is called
collar or beam.
2) the raising-up of tie beam checks the tendency of sagging due to further
increase in span or expressive loading conditions.
3) This collar beam roof is designed for spans varying from 4to 5.5 mt.

16. 2. Purlin Roof:-
i. In this type of roof, additional members called purlins are
introduced to support the common rafters at intermediate points.
ii. These purlins are required for roofs with span more then 5.5 mt.
iii. The maximum span of the common rafters is usaully taken as 2.5
mt.

17. types of trusses………….
 King Post Truss
 Queen Post Truss
 Mansard Roof Truss
 Scissor Truss
3. Triple-membered or trussed roof:-
TRUSS:-
In architecture and structural engineering, a truss is a structure
comprising one or more triangular units constructed with straight
members whose ends are connected at joints referred to as nodes.
1) These roof consists of three sets of members common rafter, that is
partially supported by purlins, which, in turns , are carried by trusses.
2) In roof trusses common rafters distribute the weight of the roof covering
material, snow (if any) ,wind pressure to the purlins which transmit this
load to trusses, and the purlins, in their turn transfer the weight to the
walls.
3) It is used when span exceeds 5 mts.

18.  King Post Truss :-
 A king post truss consists of a vertical king post that joins the center of the tie beam to
the ridge of the rafters .
 Angled struts are usually used as additional members to join the king post and the
rafters.
 The king post truss is an example of a closed truss.
 It can also be built of combination of wood and steel.
 It can be used for spans upto 8m.

19.  Queen Post Truss :-
 A queen post truss consists of two vertical queen posts that are joined at equal distances
from the center of the tie beam to the rafters.
 They are also connected by a horizontal member at the heads.
 This truss can span greater widths than a king post truss.
 It can be used for spans upto 10m.

20.  Mansard roof Truss :-
 This wooden truss is named after the name of an architect Francois mansard, who first
designed this truss.
 This is the combination of king post & queen post trusses.
 The truss has two slopes, lower slope varies from 60 to 75 degrees & upper slope varies
from 30 to 40 degrees.
 This span is used up to 7.5 mt.

21. Scissor Truss :-
For such roofs, some form of the scissors truss (so named from its resemblance to a pair of
scissors) is most often used.
 When correctly designed with members of the proper size, and with the joints carefully
proportioned to the stresses, the scissors truss makes a very good truss for supporting
the roof over halls and churches.
 It is may be up to a span of 48 feet, but above that, they should be used with much caution.

22. Timber joints:-
Butt joint :-
The butt joint is so called because one piece of stock is butted up against another.
The timber is fixed in place then fixed in place using nails or screws.
This joint is a positive permanent strong joint when fixed using adhesive .The
long length of glued area is very beneficial to the resulting strength .The in-line version
is often used to produce a long length of timber / glued laminate from shorter lengths
.The corner version is used for producing strong drawers boxes etc .The joint if made
even stronger if the fingers are made using dovetail form.
Finger joint :-
Butt joint In-line finger
jonit
Corner finger joint
CONSTRUCTION TECHNIQUES

23. Mitre joint :-
This joint is in effect this is an angled butt joint, sometimes relying on adhesive
alone to construct it. It requires accurate 45 cutting, however, if the perfect 90° corner is
to result. Additional fastening methods such as biscuits, splines etc are used to reinforce
the strength of the joint. Used for picture frames and furniture items.

24. Lap joints :-
Another simple joint is the half-lap joint. This requires the removal of stock to
exactly half of the overall thickness of the piece, in order that a similar piece can mate with
it. This technique is also used in the cross-halving joint .
Lap joint
Cross halving -Lap joints :-
Another simple joint is the half-lap joint.This requires the removal of stock to
exactly half of the overall thickness of the piece, in order that a similar piece can mate with
it.This technique is also used in the cross-halving joint .
Cross halving-Lap joint

25. Dowel joints :-
This is a relatively strong version of the corner butt joint. The joint is made
permanent using adhesive. The joint is clearly a fastening method which is not suitable for
heavy loads.
Dowel
joint
Mortise & tenon joints :-
This joint is a strong and frequently-used joint for assembling a variety of
products where strength and reliability are required .The mortise can either be a through
mortise, as shown, or a blind mortise that only partly penetrates the stock .The joint is
made permanent using adhesive .Dowels are also used to prevent separation.
Mortise & tenon
joint

26. Dovetail joint :-
The dovetail joint is a variation of the finger joint which provide positive
resistance to lateral separation. It is often used for drawer fronts .The joint is difficult to
produce but when correctly made is a strong positive joint. The joint is generally bonded
using adhesive.
Tongue & Groove joint :-
This is a very popular joint in the building industry providing a very convenient
method of accurately fixing flooring boards to produce flat surfaces which are
aesthetically pleasing - in this application the joints are generally not bonded using
adhesive. When the joint is used for structural purposes with adhesive , the joint provides
accurate positioning with good strength.
A variation of this joint is to have grooves in both boards an a separate spline as a
fastening/fixing method.
Tounge & Groove
joint
Dovetail joint

27. Interior stair
Stairs are constructed using solid timber stringers as support for the treads and risers.
The treads are housed in rebates in the stringer and held in place by wedges and glue blocks. A stringer
that closes off the ends of the treads and risers is a closed stringer. If the stair is built between walls the
stringer may be called a wall stringer. In this case the stringer is attached to the wall and transfers the
stair load directly to the wall. It is generally sized to accommodate the tread and riser, and align with
skirting. Stringers may be sized for the horizontal span using the joist Where the stringer is rebated to
house the treads and spans between the floor levels, the thickness of the stringer should be increased by
the rebate depth.
The stringers are routed out to a minimum rebate depth of 13 mm. It is important that the wedges hold
the treads and risers securely into the rebated stringer. Failure to secure the treads and risers will cause
‘creaking’ of the stairs.
TIMBER STAIRCASE
Exterior timber steps
A simple form of stair can be constructed from solid timber to provide access to exterior deck areas
using treated timber. The treads can be attached to the stringers with by50 x 50 mm brackets. The stair
timber and fixings used should meet the same durability requirements as the deck construction.
Exposed bolts and other fastenings will need to be type 316 stainless steel or epoxy coated hot-dip
galvanized steel.
Timber treads need to be coated with a non-slip finish or grooved to provide a slip resistant surface.
Balustrades and handrails will be needed if a fall greater than one meter is possible.

30. The timber-frame building method is one of the simplest, most economical, adaptable
and environmentally friendly methods of building available. It is also the most common
method of construction for all new houses in Scotland.
Timber framing is the method of creating framed structures of heavy timber jointed
together with various joints, but most commonly originally via lap jointing, and then later
pegged mortise and tenon joints.
 Framing construction is a building technique based around structural
members, usually called studs, which provide a stable
frame to which interior and exterior wall.
 Coverings are attached, and covered by a roof
comprising horizontal ceiling joists and sloping
Rafters (together forming a truss structure)
-all of which are covered by various sheathing materials
- to give weather resistance.
TIMBER FRAMING IN CONSTRUCTION

32. Timber flooring
 Floors are used to give lateral restraint to walls, and where the joists run parallel to the
wall.
 Normally straps need to be positioned every 2m along the wall, but up to 3m is
acceptable where this is to allow the formation of a stairwell or similar opening in the floor.
 Around stairwells and similar openings it is often necessary to use trimmer beams to
support the
ends of joists.
Where joists support a partition wall or under baths they usually need to be 'doubled up'
to support the increased localized loading.
On joist spans over 2.5m, strutting is required to prevent joists twisting when loaded. For
spans of between 2.5 and 4.5 m only one row of strutting is needed, at the mid span
position. For spans over 4.5 m two rows of strutting will be required, positioned at the one
third and two third span
positions. Solid strutting should be at least 38 mm thick timber extending to at least three
quarters the depth of the joist. For example, 200 x 50mm joists would need at least 150 x
38mm timber used as strutting. Herringbone strutting should be at least 38 x 38mm timber
but can only be used where the spacing between the joists is less than three times the depth
of the joist. Hence for a 150 x 50 joist, herring bone strutting can only be used up to a
spacing of 450mm but for a 200 x 50 joist, a spacing of up to 600mm would be
satisfactory. See the details below.

34. DHAJJI WALL CONSTRUCTION
In certain regions the construction system constitutes the erection of a timber frame work
of uprights, beams and braces with dressed stone blocks as an in-fill material without any
cementing material.
 Main posts should be 4 to 6 feet apart.
 With this spacing ,the main posts must be 4”x 4”
 With no main posts (except the corners), the vertical boards can be 2”x 4”.
 But they must be maximum 2 ft Apart.

35. ADVANTAGES
Lighter structure
Used less material
Quicker to erect
More economical
Aesthetics, appearance, feel important
DISADVANTAGES
 Not used in longer spans
 Very Light structures
 Less fire resistance
 Increased versatility
 Now many other economical materials available

36. PRESERVATION OF TIMER
It is the process of protecting or preserving the timber structures from the attack
of destroying agencies such as moisture, dry-rot, internal decay, fungi, insests,
etc. preservation also ensures increased life of timber and better durability.
TYPES OF PRESERVATION
a) Oil preservatives
b) Water soluble preservatives
A. OIL PRESERVATIVES:- They are generally employed for outdoor & wet
exposure conditions. Although they posses high toxicity & non-corrosive
quality but they offer painting difficulties. They are adopted for posts, poles,
piles, etc.
B. WATER SOLUBLE PRESERVATIVES:- these preservatives are commonly
done in interior wood work since they are washed away by rain water. They
are colorless, odorless, and involve very little fire hazard.

37. MEATHODS OF PRESERVATION
I. Charrying, tarrying & creosoting
II. Surface application
III. Soaking treatment
IV. Hot & cold process
V. Pressure process
1. CHARRYING, TARRYING & CREOSOTING
a. Charrying:- it is the process of preserving timber without using preservative.
In this process, timber to be preserved is kept wet for half hour and then
burnt to charcoal over wood fire. Finally it is cooled or quenched with
water. This method is used for posts, piles etc.
b. Tarrying:- it is a process of coating the timber with coal tar while hot. Door
and window frames, piles, etc. built into the walls and ground are generally
tarred.
c. Creosoting:- it is a process of applying creosote under pressure to the
timber stacked in an air-tight cylindrical vacuum chamber.

38. 2.SURFACE APPLICATION
a. Brushing:- in this method hot oil preservative solution is applied liberally in several
coats on the timber surface by good quality brushes.
b. Spraying:- in this method solution of preservative is filled in a spraying pistol &
then applied on timber surface under pressure. This is more effective and superior
to brushing.
c. Dipping:- in this method timber to be treated is dipped for a short period in
preservative solution. This gives better penetration to brushing or spraying.
3. SOAKING TREATMENT
In this process the timber is submerged in the preservative solution for long time until
the required absorption is obtained.
4. HOT & COLD PROCESS
This is considered to be the most efficient non-pressure treatment process. In this
timber is stacked in the tank and cold preservative usually creosote is then run into
the tank till the timber is completely submerged. The preservative Is then heated to
about 85-95 degree and maintained at the temp for some time.. The tank is then
allowed to cool down. During this alternative process of cooling and heating, the
air in timber first expands and then contrast which creates a partial vacuum. This
vacuum sucks the preservative into the timber.
5. PRESSURE PROCESS
In this process, preservative is injected under pressure into the timber. This is most
effective method of treating timber with preservative.

39. HIMACHAL PRADESH