Timber Treatment Techniques: How to Extend the Lifespan of Your Wood

Timber Treatment Techniques: How to Extend the Lifespan of Your Wood

Posted by Daryl Schmidt on 31st Jul 2023

Timber Treatment Techniques: How to Extend the Lifespan of Your Wood

Timber preservative treatment serves the crucial purpose of prolonging the lifespan of wood by providing resistance against decay, insects, weather, and fire. Various types of timber preservatives are utilised to achieve this enhanced durability. These chemical treatments deeply penetrate the wood cells, extending their overall service life.

Increasing timber's longevity significantly improves its durability, allowing for extended usage and reliability. Moreover, timber treatment offers an effective shield against insects and fungi, safeguarding the wood from potential damage and deterioration over time.

In this blog, we will explore some common techniques employed for timber treatment. These methods play a vital role in preserving wood and ensuring its long-term usability, making it a crucial aspect of using timber in various applications.

Common Timber Treatment Techniques

Coal Tar

One preservation method involves using Coal Tar, wherein the timber surface is coated with hot liquid tar obtained from heating coal tar. Despite its unpleasant smell and paint-inhibiting properties, Coal Tar proves cost-effective and exhibits good fire resistance, making it ideal for door and window frames. This technique can be used to treat timber lining boards.

Boron Salts

Boron salts are effective in protecting timber from insect borers. The process involves soaking freshly sawn, unseasoned timber in boron salt solutions, allowing the salts to diffuse through the wood. Boron treatments are especially favoured for appearance grading, as they do not alter the wood's colour or appearance. This treatment can be applied on pine timberor timber blackbutt as its appearance remains unchanged. However, one limitation is that boron is not fixed within the timber and may be leached, restricting its use to interior applications like flooring and joinery protected from external weather conditions.

CCA (Copper, Chromium, and Arsenic Salts)

Another popular wood preservative method is CCA (Copper, Chromium, and Arsenic salts). CCA reacts with wood cell components, fixing copper, chromium, and arsenic into the wood's structure. Arsenic protects the sapwood from insect attacks, while copper and arsenic prevent fungal degradation. The chromium component ensures high resistance to leaching, allowing CCA-treated timber to withstand exposure to the elements or in-ground use.


ASCU is a unique form of timber preservative available as a powder. It is dissolved in water to make the preservative solution applied through spraying. ASCU is made up of various components like copper sulphate, hydrated arsenic pentoxide, sodium dichromate, blue vitriol, or potassium dichromate. The solution effectively eliminates white ants, and ASCU-treated timber can be further coated with paint or varnish.

LOSP (Light Organic Solvent-borne Preservative)

In this method, a light organic solvent is used to introduce preservatives into the timber. At the last stage of the treatment, the solvent is pulled out, leaving only the preservative behind. LOSP-treated timber retains its appearance, making it suitable for applications requiring quality aesthetics, such as external joinery and house framing. The wood does not swell during the timber preservative treatment, making it appropriate for finished items like mouldings and joinery. LOSP-treated timber can be painted with acrylic or oil-based systems, but it is not recommended for in-ground use.

Chemical Salts

Chemical salts, including copper sulphate, mercury chloride, and zinc chloride, can be dissolved in water to create liquid preservative solutions. These salts are odourless and do not ignite when exposed to flames.

Oil Paints

For well-seasoned wood, oil paints serve as effective timber preservatives. Applying 2 or 3 coats of oil paint prevents moisture from damaging the timber. However, if the wood is not adequately seasoned, using oil paints may trap sap and lead to decay.

Solignum Paints

Solignum paints are applied in a hot condition as a wood preservative for treatment against white ants. The paint is applied via brush and can be combined with colour pigments, enhancing the timber's appearance.


Timber treatment is an essential part of the longevity of timber. Especially for timber that will be used outdoors or in harsh climates or wet regions, applying the right kind of timber preservative is important to ensure the durability of the wood.

If you are looking for high-quality, well-treated, preserved timber, contact our team for your enquiry.