Application

Following are the application methods adopted for preservation of timber : 

• Brushing 
• Charring 
• Dipping and steeping 
• Hot and cold open tank treatment 
• Injecting under pressure 
• Spraying 

Brushing 

The solution prepared from preservative is applied on timber surface by good quality brushes. This is simplest method and it is generally adopted for seasonal timber. The cracks should be filled up before the application of preservative. For better penetration, oil type preservatives may be applied hot and the preservative should be liberally used on the surface.  Several coats of preservatives may be applied and enough interval of time should be kept between successive coats for absorption of preservative. 

Charring 

This method of charring is rather very old and as such, no preservative is used in this method in recent times. 

Dipping and Steeping 

In this method, timber to be given preservative treatment is dipped or soaked for a short period in the solution of preservative. This method gives slightly better penetration of preservative than in case if brushing or spraying.  Instead of dipping, steeping or wetting of timber with preservative may be carried out for periods varying from a few hours to days or weeks. The depth of penetration of preservative depends on the type of timber. 

Hot and Cold Open Tank Treatment 

In this method, timber is submerged in a tank containing solution of preservative which is heated for a few hews at temperature of 85 C to 95 C. The tank is then allowed to cool down while the timber is still submerged in the tank. This method is effective in giving protection to sap wood. 

Injecting Under Pressure 

In this method, the preservative is injected under pressure into the timber. This method is similar lo the one adopted in creosoting.  This is the most effective method of treating timber with preservative.  But it requires special treatment plant.  This method proves to be essential for treating non-durable timbers which are to be used at places where there is danger of attack by fungi and insects. 

Spraying 

In this method, solution of preservative is filled in a spraying pistol and it is then applied on timber surface under pressure. The pistol works under compressed air. This method is also quite effective and it is superior than brushing.