STS Timber Wholesale Pty Ltd are specialists in timber treatment and preservation.

Our range of timber treatment options include:

  • Naturewood ACQ (Alkaline Copper Quaternary)
  • Lifewood CCA (Copper Chrome Arsenate)
  • MicroPro Sienna
  • LOSP (Light Organic Solvent Preservatives)
We can also provide custom treatment and preservation options to meet your specific needs.

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Timber Treatment Process

We operate three treatment plants in Australia from two Victorian sites located in Woori Yallock and Dandenong. Our innovative treatment process allows for differing levels of preservation from weathering conditions and protection from attack by borers, termites and decay.

Double vacuum processes are used with LOSP, suitably applied to timbers intended to be used out of ground. The LOSP treatment process is typically applied to timbers in their final shape and form.

STS Timber Wholesale treatment plant

Vacuum pressure impregnation (VPI) processes are used to apply CCA, ACQ and Micro Sienna based preservatives. These preservatives chemically react with timber making them insoluble. Being insoluble, the treated timbers are thereby suited for use in weather exposed environments. 

Vacuum Pressure Impregnation (VPI)

Vacuum pressure impregnation (VPI) is the process of sealing timber in a cylindrical tank under high levels of vacuum and pressure. Pressure is maintained until the timber cannot absorb any more treatment solution. 

Different desired results of preservation and protection can be achieved through adjusting carefully calculated levels of vacuum, pressure, time and solution concentration. Appropriate treatment specifications are determined by the species of the timber, its durability, exposure and intended applications.

All preservative formulations used in Australia must but be approved for use by the Australian Pesticides and Veterinary Medicines Authority (APVMA). For detailed information regarding timber treatment and preservation methods and regulations, contact STS Timber Wholesale or visit the Timber Preservers Association of Australia (TPAA) for a host of technical information.

Australian Timber Preservation Standards

All of STS Timber Wholesale products and services proudly adhere to or surpass the strict standards prescribed by the Australian Timber Preservation Standards.

The Australian Standard (AS or AS/NZS) 1604 series specify the requirements to protect timber used in Australia from local species of insect pests and decay organisms. There are five standards in AS/NZS 1604 series, each pertaining to different wood products 

The level of treatment timber requires consists of a number prefixed with the letter 'H' which indicates the degree of hazard. The system for determining hazard class is summarised in a table available from the Australian Department of Agriculture and Water Resources.

For detailed information and full preservation specifications, please refer to the five standards in the AS/NZS 1604 series which are available from SAI Global.


  • ACQ (Alkaline Copper Quaternary)

    ACQ (Alkaline Copper Quaternary)

    NatureWood ACQ (Alkaline Copper Quaternary) is one of a number of later generation preservative formulations and relies on copper as a fungicide and a co-biocide being an organic quaternary compound. ACQ can be used in H1 to H5 Hazard Classes and can be used in all situations including those restricted for CCA. Read More
  • MicroPro Sienna

    MicroPro Sienna

    MicroPro Sienna uses the latest generation timber preservative and “micronized” pigments that are pressure treated into the wood to give longer lasting colour. You can now buy coloured preservative treated timber that will complement your landscaping project. Micropro Sienna has received many environmental certifications. Read More
  • CCA (Copper Chrome Arsenate)

    CCA (Copper Chrome Arsenate)

    LifeWood CCA (Copper Chrome Arsenate) has been used as a wood preservative in a myriad of applications since the 1930’s including landscaping, utility poles and decks and wharfs. It is suitable for all Hazard Class situations though may not be used in childrens playgrounds, deck boards, hand railings and picnic tables. Read More
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