Frequently Asked Questions

Can I cut or machine the timber after treatment?

Cutting the treated timber to length or drilling is permissible. In extreme exposure situations the application of a supplementary coating may be required. Machining treated timber is not recommended.

We would certainly recommend that a brush-on treatment is applied to any cut ends.  We would recommend that you use a brush-on preservative purchased from your local hardware or online.

Does H3 Green Copper Quat treated timber require stainless steel fastenings?

Yes, the H3 Green Copper Quat treated wood requires hot dip galvanized or stainless steel. For H3 Clear Azole, mild steel is OK if approved for some end uses by the wood product distributor and the fastener supplier.  That is not a recommendation that Kop-Coat (or any chemical manufacturer) can make stand alone.

The corrosion threats to metals in contact with treated timbers are galvanic in nature as opposed to the more commonly understood atmospheric corrosion of metals. Hot dip galvanised (minimum 42 microns of zinc coating) fasteners should be used.

For marine environment, minimum 316 grade stainless steel is recommended.

The use of kiln dried or appropriate dried timber species is recommended for any situation where intimate contact between the metallic coated steel and timber is considered.

High grades (304, 305, and 316) of stainless steel materials perform the best on both untreated and Copper Quat Treated Timber. Use hot dipped zinc galvanized materials. Mild steel and Aluminium should not be used. Use epoxy coated fasteners only if specifically guaranteed by the fastener manufacturer for use with Copper Quat Treated Timber. Follow fastener and fitting manufacturers’ instructions.

How toxic are the chemicals to the workers and the public?

All components of the TRU-CORE® system have excellent health, safety and environmental profiles.  It contains no heavy metals or other materials which are persistent in the environment.  None of the ingredients in the TRU-CORE® System are related to any long term health effects in humans.  All preservative components of TRU-CORE® are U.S. EPA, NZ EPA, CN PMRA, and AUS APVMA-registered, carbon-based molecules which are globally accepted, well characterized and widely used in many consumer products such as cosmetics and household cleaners.

The carrier in the TRU-CORE® System is water; hence, TRU-CORE® contains no measurable volatile organic compounds (VOCs) which contribute to greenhouse gas emissions.  As with all chemicals, there are standard chemical health and safety precautions that are captured on the Safety Data Sheet of the Treated Wood.  In many cases, the amount of preservatives that are embedded into the wood fall below the Globally Harmonized System (GHS) threshold limits.

I’m interested in using H3 treated timber to build a structure over a swimming pool. Would there be any issues with the chlorine and the TRU-CORE treated product?

There are no issues using the H3 treated timber near a swimming pool, however you must utilise a very high quality exterior coating/sealant.

What product should I use for painting or staining H3 Clear Azole treated timber?

TRU-CORE H3 Clear Azole treated wood and wood products can be painted or stained to meet any outdoor colour scheme without discoloration from the preservative. Kop-Coat Australia recommends the use of high quality oil and latex based paints, stains or water repellent UV protectant coatings, as is industry accepted with treated wood. The wood must be dry and clean prior to applying any finish coating.

If initial cleaning of the treated wood is needed, it is recommended that the project be cleaned with a deck cleaning product and allow to fully dry. At this time, a clear water repellent can be added to the project.

If applied, allow 8 weeks prior to the application of a semi-transparent stain or paint. In no water repellent is added, an oil based stain can be applied to the clean, dry wood in 15-30 days from treatment date.

A water based stain can be applied to the clean, dry wood in 30-50 days from treatment date.

If the wood is left uncoated and without UV protection, the typical colour of the treated wood will naturally weather to a gray color over long-term exposure to the sun.

Users must always conduct their own tests on coatings in inconspicuous areas of the project to determine acceptability of colour, adhesion and appearance. Always follow the manufacturer’s recommendations for proper application of finishes. A topical water repellent may be applied every one to two years.

Will there be any issue with ZINCALUME® and H3 Green Copper Quat treated timber?

Yes, H3 Green Copper Quat treated timber should not be in close contact the the ZINCALUME® as this issue is straight galvanic corrosion caused by the copper and the zinc. We recommend using H3 Clear Azole treated timber in such application.

BlueScope Steel basic recommendations for the use of COLORBOND® steel and ZINCALUME® steel products:

  • Always use the recommended steel grade to suit your environment and any special corrosive influences,
  • Store material clear of the ground and protect from rain and moisture prior to installation,
  • Always use fasteners with durability equal to the material being used and which have carbon-black-free washers,
  • Avoid materials and liquids which can cause corrosion, such as lead and copper, green or CCA (Copper-Chrome-Arsenic) treated timber, uncoated steel supports, fertilisers, pesticides and abrasive cleaners.
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