Pine trees grow in many parts of the world. Treated pine is one of the most popular forms of timber used in Australia. The majority of treated pine comes from plantations in New Zealand and Australia.

Untreated pine has very little durability and cannot be used in any type of construction where robust hardwood is required. However, treated Pine has better durability and an amazing resistance to decay and termites. Treated pine is also good for hand work with because it is easier to shape and bend while also being robust as well as durable.

There are many advantages to using treated Pine. Depending on the use of the wood, there are a range of wood treatments. It may be used for a variety of applications when combined with a wide range of finishes. Treated wood has a proven track record over centuries and can still be found in centuries old houses around the world.

The specification for timber treatment in Australia is described under AS1604 for complementing legislation in Queensland and New South Wales. This document describes the treated timber hazard levels. The symbol of the format similar to XXX 02 H1 is usually marked on the timber itself. This code identifies the plant of facility where the wood was treated.

The XXX code represents the facility or plant which applied the treatment. The number (example – “02”) denotes the type of preservative used. This code is described in Appendix CI of AS1604. The number starting with H indicates the hazard level of the preservative such as:

  • H1 – Inside, above ground, dry, insect borer – other than termites hazard. Applications are decking, framing, flooring, furniture, etc.
  • H2 – Inside, above ground, dry, insect borer and termite hazard
  • H3 – Outside, above ground – Moderate fungi and termite hazard
  • H4 – Outside, in ground – High fungal decay and termite hazard
  • H5 – Outside, in ground or fresh water – High fungal decay and termite hazard
  • H6 – Marine water exposure – Marine borers’ hazard

The treatment begins with selecting the highest quality yellow pine available. The wood is checked thoroughly for any defects and then loaded into a giant container. Under extreme pressure, the chosen preservative solution is forced deep into the cells of the wood. The liquid seeps into the cell walls and interior of the cells. This wood is then allowed to dry until it is ready to be used. This type of treatment keeps most bacteria, fungi, insects, termites and even water based organisms away and keeps the wood protected for years.

There are many types of treated pine wood:

CCA – Copper Chromate Arsenic
Ecowood – A safe alternative to CCA which uses a preservative approved world wide

Creo – Creosote is impregnated into the timber under heat and pressure.

There are some caveats when using treated wood:

  • Do not burn treated wood and take care to discard it only in accepted areas.
  • Wear gloves when working with treated wood.
  • Wear a dust mask and cover your eyes with safely glasses when working with treated wood.
  • Wash skin thoroughly if it comes in contact with the wood.
  • Do not use treated wood near sources of drinking water or water in which people or animals may swim.
  • All the garbage such as sawdust and other debris should be removed immediately.
  • Wash the clothes that were worn at the time of building separately from other clothes.
  • Do not use treated wood in places where animals may come in contact with it such as bee hives, animal pens, fences, etc.
  • Use treated wood only in dry areas. If wet, the preservative may leach into the ground. Wet wood may also be susceptible to fungi and mould.

Many of the companies that do this treatment may guarantee the performance of the treated wood for a maximum number of years.

Treated pine may be used in many building projects such as:

  • Decks
  • Gazebos
  • Tables
  • Banisters
  • Handrails
  • Framing
  • Fences
  • Outdoor furniture
  • Pergolas

Always check the national, federal and state codes before starting with any construction using treated lumber.