Wood is the only renewable building material within the three major building material types. In exterior applications, wood is subject to deterioration from natural elements and biological attack, but when properly protected, its service life can be extended for many years. The most effective way of protecting exposed wood is the use of wood preservatives. Preserved wood products can have 5 to 10 times the service life of untreated wood. This extension of life saves the equivalent of 12.5% of Canada’s annual log harvests (source durable-wood.com).
The preservation of the wood is important, especially when it is specified for use in critical infrastructure applications such as railway ties, bridge timbers, utility poles and guardrail posts for highways. Pressure treated wood ensures that these critical structures remain strong and safe for the duration of their service lives. Pressure treated wood products are also commonly used in agricultural applications such fence rails, posts and building poles, as well as in commercial decks, fences, and other heavy duty outdoor applications. Depending on the required application and the level of protection needed for the wood products, there are a variety pressure treatment methods and approved preservatives that are available in Canada.
Pressure treatment is a process that forces preservatives into the wood to protect against fungal decay and destructive insects such as termites and marine borers. In Canada, wood preservatives are registered with Health Canada’s Pest Management Regulatory Agency (PMRA). Individual treating facilities undergo regular environmental assessments and follow the recommendations for the design and operation of wood preservative facilities as outlined in Environment Canada’s Technical Recommendation Document (TRD).
