It’s used virtually everywhere; in constructions, for building structures, even in garden landscapes around you. To ensure the sustainability of this magnificent product, we result in treating it for preservation purposes.

Getting to understand the processes, types of treatment, the terminology associated with the same, can be quite confusing. Here we’ll help break it down to you and enlighten you on all the essential aspects surrounding treated timber.

Treated vs. Untreated Timber

If you prefer to go the natural way, untreated timber should be your choice. Besides, it is cheaper when compared to treated wood. Considering that it’s free from chemicals, this is the ideal for projects involving people and food.

However, there is a trade-off to this; cheap is expensive in the long run. Untreated timber lacks longevity and will not serve you for as long as you’d have anticipated.

So, why should you opt for treated timber?

The main reason is increasing its longevity. Forces of nature are the greatest enemy to your timber. Whether in outdoor landscaping projects or indoor decking, nature will always find a way to attack your untreated timber. Also, there exist some forms of treatment that are not hazardous.

Treatments protect from insects, wearing off, as well as rotting of your timber.

Here are some common fungi and wood-boring insects you should be aware of:

  • Pore fungus
  • Dry wood termites
  • Dry rot
  • Termites
  • Deathwatch beetle
  • Wood boring weevil
  • Cellar fungus
  • Common furniture beetle

The treatment preservatives used should be registered under the Australian Pesticides and Veterinary Medicines Authority (APVMA) to ensure your safety. The body ascertains the effectiveness as well as its safety before approving the treatment method.

Types of Timber Treatment

There exist two main types:

Copper Chrome Arsenic (CCA) – CCA Timber Treatment

  • It is the most common type of treatment in Australia
  • Applied using pressure treatment
  • Commonly used in veranda posts, weatherboards, building timber, marine applications, retaining walls, farm fences, timber sleepers, and fence lattices.


  • Cost friendly
  • Readily available compared to the others.
  • Lasts more than a decade if in outdoor use.


  • Due to some concerns raised with regards to the chemicals used, it is restricted by the APVMA in uses where contact serves as a risk.

Alkaline Copper Quaternary (ACQ)

  • Developed to combat the safety concerns raised in CCA treated timber.
  • It’s approved for use in areas where CCA is banned.
  • Picnic tables, children’s play equipment, domestic decking, garden furniture, handrails, among other applications involving close skin contact.


  • Free from arsenic, implying reduced toxicity and hazard levels.
  • Other advantages are similar to those in CCA.


  • Not as readily available as CCA.
  • Costs more than CCA due to its limited availability

Classification based on hazard levels

There exist different levels of preservation, depending on the hazard the wood will be exposed to. Accordingly, there exist different hazard classes, running from H1, through to H6.

The higher the degree, the higher the protection level. Note that the high-level classified wood can be used in low-level applications.

Timber for indoor use, for example, is categorised under the H1 and H2 exposure. The low-level protection is used in areas where the timber is protected from moisture, with the only hazard being insects and termites.

The preservation processes

  • First, the timber is transferred into the treatment vessel, a large horizontal cylinder.
  • The cylinder’s door is closed, and all air is suctioned out to create a vacuum. In creating a vacuum, the air is sucked out of the wood cells
  • Next, osmose preservative is filled into the vessel. Pressure helps force the preservative into the wood cells
  • The chemical is emptied, and a vacuum reapplied
  • Timber is left to dry.

Common misconceptions

  • Timber treatment is weatherproof

You should note that the colour of timber greys and may crack over time as it absorbs moisture. Depending on your local conditions, your timber may either lose or gain some moisture which alters its look.

It is pivotal to apply a surface coat for protection against weathering. To keep your timber looking good for long, consider using a water repellent, stain repellent, or paint.

  • Preservatives in treated timber is absorbed by vegetable in your garden

Wrong. Studies reveal that garden crops do not absorb CCA. However, in some few vegetables such as carrots, small organic, and non-toxic amounts were detected; which are easily removed by peeling.

At Paul’s Rubbish Removal, our goal is spread awareness on the different types of junk that we counter at home or at work. This gives us a better understanding on how to dispose of such items in the most efficient way. With our rubbish removal services, we dispose of all junk responsibly so that we minimise the impact it has on the environment.

If you have treated or untreated timber that you need to dispose of, our team will take care of it for you. No matter how much or what condition it is in, we’ll arrive in a timely manner at your site to collect and take away your timber waste. Please contact Paul on 0407 125 125 for enquiries and bookings.

    cleanup crew


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