Seasoning of Timber is the process of removing moisture from freshly cut timber in order to annihilate defects like warping in timber. Timber seasoning also makes timber viable for the building construction and other engineering applications. Air drying is the most commonly used method of timber seasoning. Other methods of seasoning of timber include Kiln Seasoning, Timber Seasoning, Chemical Seasoning, Seasoning by boiling, etc.

This article shall uncover invaluable details regarding different types of seasoning of timber as well as their advantages and disadvantages. The topic is important for various exams including GATE CE, SSC JE CE, and RRB JE Civil.

What is Seasoning Of Timber?

Seasoning of timber is the process of reducing the moisture content of timber so as to enhance the engineering properties of timber and make it more suitable for use in engineering applications. Seasoning typically reduces the moisture content of timber to about 15%. A large number of assorted factors are taken into consideration during timber seasoning. These include the type of wood, thickness, desired moisture content, including other factors.

Seasoning Of Timber

Timber seasoning is a critical process in construction that involves allowing wood to dry before use to prevent moisture-related problems. This controlled procedure aims to reduce the moisture content of the timber to a specified level, and eliminate the sap from the wood to prevent decay. By seasoning the timber, it becomes more durable and less susceptible to decay, making it an essential step in ensuring the quality of timber structures.

Seasoning Of Timber Purposes

The main objectives of Seasoning of Timber are:

• Enhancing the properties of timber to make it usable for engineering purposes. 
• To nullify surface deformities and defects in timber like knots, cracks, warping, etc.
• Seasoning of timber is required to reduce the shrinkage tendency in timber.
• To make the timber more workable and to lower the weight of timber for easy transportation and handling.
• Ensuring well-controlled conditions for timber.

The two methods of seasoning of timber are:

• Natural Seasoning
• Artificial Seasoning

Natural Seasoning of Timber.

In this methods of seasoning of timber, timber is seasoned by placing it in the open air, with a provision of ventilation between the individual timber logs. Natural seasoning can be of two types: Water seasoning and Air seasoning.

Water Seasoning

• In this type of seasoning, timber is immersed in a flow of water. 
• This technique facilitates the removal of sap in the timber. 
• Water seasoning of timber can take about 2 to 4 weeks. 
• After 4 weeks, the timber is dried. 

Air Seasoning

• In air seasoning of timber, logs of timber logs are stacked in layers in open air.
• Sufficient gap is ensured between the logs to ensure continuous ventilation.
• The logs are place on top of a platform which is 30cm above the ground. 
• Ventilation of air through the logs facilitates sufficient reduction of wate content in timber.
• Air seasoning of timber is a slow process of seasoning of timber.

Factors Affecting Seasoning of Timber

The rate and quality of timber seasoning are influenced by several natural and operational factors. These elements must be considered before choosing a suitable seasoning method, as they affect moisture loss, drying time, and the final strength of timber.

Advantages of Natural Seasoning of Wood

Some of the noteworthy advantages of natural seasoning of timber are:

• Seasoning improves the dimensional stability of timber. 
• It prevents decay in timber. When the water content in timber is limited to 20 percent, timber can be considered to be safe against rotting.
• Seasoning makes timber lighter, and thereby facilitates easy handling and transportation. Seasoning of timber reduces its weight by at least 35%.
• It makes timber sufficiently stronger. As wood dries, its strength, stiffness, and hardness all get improved. The strength of timber generally improved by 50 percent upon reducing the moisture content in it to 15 percent.

Disadvantages of Natural Seasoning of Timber

• Seasoning requires timber logs to be stacked for long durations of time. During this period, timber is prone to damage by fungus and insects.
• Large open area is required for Natual timber seasoning.
• In this type of seasoning, timber edge has a tendency to dry out pretty quickly due to direct exposure to air. 

Artificial Seasoning of Timber

• Although Natural seasoning is economical and ensures quality standards of timber facilitated by proper seasoning, it is a time consuming process. 
• An effective alternative to natural seasoning is the artificial seasoning of timber. 
• In artificial seasoning, timber logs are seasoned in a quick span of time.
• The various types of timber seasoning are:

1. Seasoning by Boiling
2. Kiln seasoning of timber
3. Chemical seasoning
4. Electrical seasoning

Seasoning by Boiling

• In this method of artificial seasoning, timber is boiled in water for 3 to 4 hours.
• After that, timber is allowed to dry. 
• However, boiling seasoning of timber is not an effective method for large quantity of timber.
• In such cases, seasoning is done by passing hot steam through the timber logs.
• This method of seasoning develops sufficient strength and elasticity in timber.
• However, it is an uneconomical method of seasoning of timber.

Kiln Seasoning Of Timber

• In this method, hot air is passed through timber placed in a chamber.
• This air circulates between the timber logs and reduces the moisture content.
• Heating coils are used to raise the temperature inside the chamber.
• Once a suitable temperature is reached, the moisture content in timber gets sufficiently reduced. 
• Kiln seasoning of timber is an uneconomical process of seasoning.

Chemical Seasoning

• In chemical seasoning of timber, salt solution is used for timber seasoning. 
• The solution absorbs water from the timber at a rapid rate, thereby facilitating quick seasoning. 

Electrical Seasoning

• This method of seasoning of timber is also called rapid seasoning.
• In Electrical seasoning of timber, high frequency AC currents are passed through timber.
• Subsequently, the electrical resistance of timber is measured.
• Once the electrical resistance reaches to predetermined levels, the process of seasoning is halted.
• It is an uneconomical method of timber seasoning.

Advantages of Artificial Seasoning of Timber

• This type of timber seasoning can be done quickly.
• It can be used in areas that are prone to heavy rainfall, wherein natural seasoning cannot be conformed to.
• It is performed in a well-controlled environment.
• Artificial seasoning ensures sufficient development of strength.

Disadvantages of Artificial Seasoning

• It is highly uneconomical and unaffordable.
• It cannot be used for seasoning large quantities of timber logs.
• This type of seasoning of timber requires thorough supervision.

Comparison Between Natural and Artificial Seasoning

Timber seasoning can be carried out naturally or through artificial means. Both methods serve the same purpose but differ in time, cost, and suitability. The table below compares their features to help identify the most appropriate method.

Seasoning of Timber forms an important topic in the syllabus of different state-level and central-level examinations of civil engineering. If you want to give your preparation a proper direction, get enrolled in the AE/JE Civil Coaching and GATE Civil Coaching  available on the Testbook App.

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