The ultimate objective of timber preservation is to give an extended service life to any timber structure. This is achieved by placing preservative chemicals, which are antagonistic to wood destroying agencies, into the wood microstructure.

How is the preservative applied to the timber?

There are a number of methods of timber preserving processes, but vacuum pressure methods have proven to be most effective.  The vacuum pressure method which Koppers Arch Wood Protection, the manufacturer of the Tanalised range of product, uses is as follows:

• The wood is placed in a container (pressure vessel) which is then 90% filled with preservative.
• A vacuum is drawn for a specific time and then the pressure vessel is allowed to flood to 100%. Pressure is applied until the correct amount of solution has impregnated into the wood.
• The pressure vessel is emptied of solution and a final vacuum is drawn.
• The timber is withdrawn from the container and dried.