Commonly Used Preservatives For Wood And Their Effectiveness

When treating timber to ensure the length of its life and prevent as much deterioration as possible, there are different methods according to what is needed. Most wood that is used for house stumps must be treated when it is at least partially dry, for both moisture and termites, which can require different processes of treatment. Some can be added together to achieve the same result. While there are different preservatives, the chemicals that are commonly used as an ingredient in the different preservatives are as follows:

Boron Salts

As a treatment for insects, Boron Salts are considered the most effective wood preserver. Unfortunately, it does not ‘fix’ into the timber, so can leach out if the wood is exposed to the elements, such as weather and water. If the area is adequately shielded from the elements this can be an effective method of protecting against termites and is relatively easy to apply.

Copper Chrome Arsenic (CCA)

As one of the most commonly used preservatives in Australia, Copper Chrome Arsenic is one of the most effective treatments to use for prolonging the life of your timber. This chemical is fixed to the timber through a vacuum pressure method, and the elements of arsenic and copper combined will prevent the wood from insects and fungal attack. The only downside to Copper Chrome Arsenic is that it does not prevent the timber from showing signs of weathering, so if the area is to be seen it will need to be painted or stained to maintain appearance.


Due to the process of fixing Creosote to the timber, it usually has a pungent smell and bleeding which occurs, so it is not often used for domestic situations. It is an excellent preservative, especially when it has been pressure impregnated into the timber under vacuum. A newer version of this chemical has been developed recently, known as Pigment Emulsified Creosote (PEC) which is a cleaner alternative and is more easily handled.

Light Organic Solvent Preservatives (LOSP)

This preservative is regarded as a fungicide for preserving the life of timber, but it can have an anti-insect chemical added to it, to allow it to serve the function of preventing insect infestation as well. These preservatives are typically spirit borne so they are an effective method if you do not want to rewet timber that has already been dried.

Talk to our experienced timber experts at Black and White Houseraising and Restumping about which timber preservatives would be best to use for your job.