Different timber treatments

 In Timber Education Blog

There are many reasons for treating timber. Treatment provides protection against insect attacks, fungal decay, termites, and weather damage. Treatment is also used for durability, longevity and preservation of the timber. The level of treatment must be appropriate for the intended use of timber. There are different treatments dependent on what the timber is used for e.g. exterior vs interior applications.

Different types of timber treatment

  • Boron Treatment
  • ACQ Treatment
  • CCA Treatment
  • ACQ Treatment
  • LOSP Treatment
  • MCA Treatment

Boron Treatment

Boron Treatment provides protection against insect and fungal attacks. Timber treated with Boron is suited to interior construction such as wall framing, rafters, paneling, and enclosed floor joists. This treatment is not suitable for weather exposed conditions.

Boron treatment may be applied to timber by dip-diffusion, pressure-diffusion or pressure treatment processes.

ACQ Treatment

This treatment is a waterborne, Alkaline Copper Quaternary preservative system developed to provide long-term protection to timber exposed in exterior applications. The ACQ NatureWood system MLC use is based on Copper combined with a quaternary ammonium compound and applied to timber by pressure treatment. These compounds are effective fungicides and termiticides. This provides protection against a broad range of decay, fungi, borer and termites.

CCA Treatment

The purpose of CCA treatment is to provide a longer-term protection to timber exposed in exterior applications.  CCA perseverative is a waterborne, Chromated Copper Arsenate perseverative system applied to timber by pressure treatment. It is an effective fungicide and termiticide providing protection for a range of decay fungi and wood boring insects. It is a proven formulation designed to provide lasting protection for timber products used in 2 main applications. CCA H3.2 for timber not in ground contact and CCA H4 for timber that is in close proximity to, or actually enclosed in the ground. A higher treatment retention of CCA H5 is available also, most commonly used for load bearing piles in ground contact.

CCA is regarded as one of the most effective timber preservatives available. CCA products are long lasting, durable, and designed for outdoor construction. It is the most accepted and widely used timber preservative in Australia and New Zealand. CCA pressure treated timber will last for decades, even in harsh outdoor exposures.

LOSP Treatment

LOSP stands for Light Organic Solvent Preservative.  It contains a combination of propiconazole and tebuconazole to protect against fungal decay and Permethrin to provide lasting protection from termites and other wood boring insects. LOSP provides an “envelope seal” of the timber and any holes drilled or cuts made in the timber should be resealed after. It is a recommended practice to apply a reputable stain or paint to LOSP timber in exterior applications.

MCA Treatment

MCA or Micronized Copper Azole, is a copper-based wood preservative used in the pressure treatment of timber. The chemistry of MCA impregnation is also different from typical wood preservative treatments, the copper is present in microscopic particles suspended in water and injected into wood. This preservative penetrates the timbers cellular structure providing long-lasting resistance to decay and termites. MCA treated timber can be used in residential applications above ground, in ground contact or in freshwater contact. The benefit of wood treated with Micronized tebuconazole is the long-term protection of timber and its reduced toxicity compared to earlier pressure treated wood varieties.

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