Wood which obtained from trees is used as a natural building material for construction is termed as timber.
Now I will tell you the complete details in this blog form, the complete guide about timber which generally used in various construction sectors as a construction material.
From an old English word TIMBRIAN the word timber is derived.
Various timbers are used to make the following items.
Railway sleepers, bridges, pipes, furniture, decorative pieces, doors and windows, packing material, piles, cartwheels, furniture, scaffolding, temporary bridges, matchbox, boat, dhupsali, poles, pen, rafters, keychain, flooring, tableware’s, roofs, lintel and arches, partition walls, paving blocks, etc.
Explore the guide topics in details:
- Cross-section Of Exogenous Tree.
- Requirement Of Good Timber
- Seasoning Of Timber
- Types Of Timber
- Advantages And Disadvantage
- Importance of timber
Cross Section Of Exogenous Tree
Requirements Of Good Timber
The rings should not be far from one another. It should have a dark uniform color and it should have a sweet smell. It should be dense. They should also be workable, with good machinability. It should have a uniform texture.
When it is struck it should produce a sonorous sound. For the most part, the medullar rays should be compact. However, it should not contain any imperfections like ruptures, dead knots, shakes, etc. There should not decay of this material due to fungi and insects like white ants and termites. Generally, it should be free from crakes, splits, warp, etc.
Seasoning Of Timber
When a tree is fresh cut, the wood contains a considerable quantity of water in the form of sap and moisture. It is necessary to remove this water from the wood before it can be used in any construction work.
Seasoning is required for following purposes
- Generally to reduce the weight of wood by removing useless water or sap of wood,
- Also to increase the strength of wood. Water or moisture in cell walls and cell cavities cannot bear any loads.
- It reduces transportation cost because seasoned ones are lighter than green ones
- It also helps to increase workability
- Seasoned ones can also accept color, paint, and varnish.
- Green ones may warp, deform and shrink within a short time but seasoned types have not such defects.
- Since seasoned timber is more durable so it gives longer life.
Methods of Seasoning
- Natural or air seasoning
- Artificial or kiln seasoning
- Chemical seasoning – Salt seasoning
- Seasoning by boiling
- Electrical seasoning
(1) Natural seasoning
(a) Air seasoning:
Firstly wooden logs are cut in the form of sleepers and planks. Then Stack ground is prepared below the ground level on dry land.
Wood is placed in a stack in such a manner that enough space is left between two layers and free circulation of air around each part. Since the stack should be safe from direct winds and direct heat, there should be a uniform rate of evaporation of wood moisture and sap.
Generally, this is a slow and economical process. But moisture content cannot be brought below 16-17%.
(b) Water seasoning:
Firstly freshly cut wooden logs are placed in running water. Then the sap from cells and walls are washed out. Afterward logs are taken out and placed for air seasoning. Genarally this process takes lesser time compared to air seasoning. Also The Quality of seasoning is also better.
(2) Kiln seasoning
Firstly it is staked nicely in the kiln with the aid of maintaining open areas for warm air circulate
Then it is staked properly in the kiln by keeping open spaces for hot air circulation. Initially temperature is maintained low slightly higher than room temperature.
The temperature is successively increased, humidity is lowered and air circulation is made quicker. This is a modern method of seasoning of it artificially. Meanwhile the content value of moisture will bring below 7%. But this method is costly.
(3) Chemical seasoning -Salt seasoning:
Firstly wooden planks or pieces are immersed in sodium chloride, sodium nitrate, or urea. Then this chemical solution will make it dry from inside. Also the Outer surface is dried by putting them in the open air.
(4) Seasoning by boiling:
Wooden pieces are immersed in boiling water for 4 to 5 hours. The sap is cleaned out. By putting them in air such treated timber dries quickly. The drawback of this method is that the seasonal ones have less strength and elasticity of fibers.
(5) Electrical seasoning:
In the first place in this method electric current is handed via portions of green wooden. Thus generated heat will dry out the moisture of greenwood. This is a quick method but heating of all walls causes weakness of timber.But this is a costly and uneconomical method.
Preservation of Timber
Generally it is used to make doors and windows and furniture of buildings.
It is eventually covered by coal tar, oil paint, or varnish to get weather resistance. Certain chemicals like copper sulfate, mercuric chloride, sodium fluoride, zinc chloride, etc. are also used to preserve woodwork from fungi, insects, termites, etc.
Types Of Timber
(A) Natural Timber
So almost 150 types of trees are used to obtain this material for building construction, structural work, paving, furniture, etc.
Indian Timber Trees:
(B) Industrial Timber:
Due to limitations in the shape and size of natural ones, industrial types are required to produce by using natural wood as raw material. Industrial timber can give more strength and life. They also have good resistance to seasonal effects. They are available in the desired length, width, and thickness.
Various manmade industrial timbers are
- Plywood’s Batten board, lamin board, metal-faced plywood, veneered plywood, multi-ply
- Impreg Timbers
- Compreg Timbers
So veneers are thin sheets or slices of wood, available in 0.40 to 6 mm thickness.
Generally veneers are used in the production of plywood’s, batten boards, and lamin boards. Plywoods are boards, which might be prepared from skinny layers of wood or veneers. After gluing, pressure may apply. The veneers are placed in odd numbers like three or more one above the other and held together in position by the means of appropriate adhesives
Plywood provides longitudinal and transverse strength. It absorbs direct shocks and impacts. Plywood prepared from more than 3 plies is known as multi-ply. These boards are light and strong. They do no longer crack or split effortlessly.
Fiberboard is prepared from wood fibers by applying pressure. The pieces of wood and vegetable fibers are collected and heated in a hot water boiler to separate wood fibers. They are cleaned and pressed between steel plates to obtain fiberboards. Fiber board’s thickness varies from 3 mm to 12 mm. They are available in lengths from 3 m to 4.5 m and widths from 1.20 m to 1.80 m.
Formica and sunmica are impreg ones. Impreg types are cured at a temperature of 150° to 160°C.
- It has low heat conductivity.
- This material has amenability to mechanical working.
- Also, it has a small bulk density.
- It has relatively high strength.
- A unique property of susceptible to decay.
- It is susceptible to flame.
- Its volume changes with moisture content.
- There is variation in strength in length and across fibers.
- They have a long life.
Advantages And disadvantages
- Timber is Light in weight compare to steel, stones, and concrete for building construction.
- Use of timber as a beam, as steps in the staircase in building construction, can save money, efforts and time.
- It is easy to cut and reshape as per desired dimensions.
- It is locally available. The workers of woodwork are easily available.
- It can be use as sill and Lintel also instead of reinforced cement concrete. Compare to R.C.C. it is cheaper, lighter, economical, and faster to construct.
- It is useful to make a door, window, ventilator, and furniture of building in construction.
- Timber catches fire easily.
- They have weather effects. It expands in dampness and especially in monsoon due to rainfall
- Also it has fault, cracks, etc. like weak points.
- They can be eventually affected by termite. Strength and life both reduces due to termite and other insects.
- It is not suitable for heavy loads and multistoried structures.
Importance Of Timber
It is generally used as walls, columns, beams, doors, and windows in building construction work. Varieties of woods are used in building construction due to its easy availability. On the positive side, it is easily available locally and also in desired sizes. They are easy to transport due to lesser weight and easy handling.
They can also be nailed and joined with fixtures as a result to get the desired sizes. It is generally used in furniture decoration of buildings. However they can be renovated easily by paints and varnishes on exposed surfaces.
Surprisingly the only material in construction sector that are 100% renewable.
Since removing the water and moisture content will make it lighter and increase the strength.
Yes, it will get rot as time passes because the moisture in the concrete moves to the timber
Timber is generally used because it is natural, sustainable, easy to work, and durable.
By Sir Abel’s Process timber can be made more fire-resistant.