Timber is the most sustainable of all materials available for construction whether you’re building a home, farm fence, bridge or shopping mall.

By Dolphin Bay

Timber from pine and eucalyptus trees – the species most commonly used for construction purposes – is not durable, making it subject to damage from water, fungus, insect larvae and the pesky termite. To prevent this natural process of decay, timber must be treated with the appropriate preservative chemical.

There is a dangerous misconception that timber simply needs to be sealed with a protective coating. Sealants merely protect against weathering and do not penetrate the timber, leaving it vulnerable to attack from insects and fungus. Make sure the timber you use has been treated by a reputable company, in line with industry standards, using the chemical best suited for its hazard class (see more detail below).

Timber treatment should take place at a treatment plant where it undergoes a vacuum and pressure-cycle process in a treatment vessel and is treated with preservative chemicals at different strengths or loadings, depending on the intended purpose of the wood. This ensures that the wood will last for its intended use.

Consumers may ask for proof that their timber has been properly treated, as all wood sold as preservative-treated timber in South Africa must comply with the relevant national standards and be marked as such. In round poles, this information is displayed on a small metal disc attached to either end or with sawn timber, the information is applied with ink stamps. In either case, the information displayed should include the trademark of the manufacturer, the hazard class, a quality mark from the South African Bureau of Standards or auditing body SATAS, and the applicable national standards number.

It is helpful to understand the various timber ‘hazard classes’ and the wood preservative that best fits each class. The hazard classifications were established by The South African Wood Preservers Association, with the South African Bureau of Standards and representatives of the timber industry.

CCA (chromated copper arsenate) is the world’s most versatile wood preservative, with the best track record. It is suitable the highest hazard classes three to five and can be used for all hazard classes, although this is not always necessary. CCA-treated timber is light green and fades to grey in time. We’ve all seen this timber in children’s timber playgrounds, boardwalks and fencing.

Dolphin Bay is a leading supplier of wood preservatives to the timber market in southern Africa since the company was established in 1996. Dolphin Bay’s product Permacure CCA is sold to 13 countries across the world, meeting international standards and has gained an excellent reputation in the industry.

“Treated timber is used for a multitude of purposes in the construction industry,” says Dolphin Bay MD Bertus Coetzee. “Make sure your timber is correctly treated, and it will serve you for decades
to come.”