This week we are talking a little about treated pine, the different grades of treatment, and which timber should be used for which purpose.
What is treated pine? Preservative treated pine is timber that has been impregnated with a chemical solution containing 2 major components, fungicide and insecticide. Because the preservatives are forced deeply into the wood, treated pine has long term resistance to decay, insects and other wood destroying organisms, outliving many naturally durable timbers in exposed conditions. It can be used for many applications, where untreated pine is not suitable for example: retaining walls, low decks, garden edging, posts and cubby houses. Untreated timber is used for purposes such as architraves, inside walls, and other areas where the timber is not exposed to the weather.
There are different grades of treatment in timber, the higher the number the better the coverage, for use in situations where the timber is in constant contact with the ground.
Treated Pine H1 (H stands for hazard level) is used to protect from insects other than termites, this timber used for furniture, interior joinery and flooring.
Treated Pine H2 protects against termites and borers, and is commonly used in house framing, flooring, and other dry situations. This timber cannot be in contact with the ground.
Treated Pine H3 protects against moderate decay, borers and termites. This timber is used for cladding, pergolas (above ground) framing and decking. This timber cannot be in contact with the ground.
Treat Pine H4 protects against severe decay, borers and termites. It is used for fence posts, pergolas (in ground) cubby house stumps and landscaping. This timber can be in the ground.
Treated Pine H5 protects against very severe decay, borers and termites. This is used for retaining walls, house stumps, building poles and anywhere outside in the ground. This timber can be in the ground.
Treated Pine H6 protects against marine borer attack and decay. This is a marine grade timber and is used in boat hulls, marine piles, jetties and landing steps etc.
Hopefully this information is helpful when planning your job, whether it be a cubby house for the kids, or some garden edging, this information should point you in the right direction. Your local hardware can help you identify which timber is treated to which level.
Have you used treated pine before? Do you plan on using treated pine?