In addition to the chemical treatments like CCA and ACQ, Azole Clear (often marketed as H3 Clear Azole or under brand names like Timbertreat A or TruCore Wood for life) is a rapidly growing choice in the Australian market, particularly for high-end residential projects.
It is a specialized water-based or solvent-based treatment that utilizes organic fungicides (Azoles) and insecticides (Permethrin) rather than heavy metals.
What is Azole Clear?
Azole Clear is an insecticide and fungicide wood preservative designed primarily for H3 (Above Ground) use. Unlike CCA or traditional ACQ, it does not leave a strong green or brown tint on the wood, making it the “gold standard” for projects where the natural aesthetics of the timber are the priority.
Key Features of Azole Clear
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Natural Appearance: As the name suggests, it is a “clear” treatment. It preserves the original color of the timber (like the pale straw of Radiata Pine or the rich tones of Victorian Ash), allowing for clear oils or light stains to be applied without being “muddied” by a green chemical hue.
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Metal-Free & Safe: It does not contain arsenic or chromium. This makes it an ideal choice for residential decking, handrails, pergolas, and outdoor furniture where people—and especially children—will have frequent skin contact.
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Engineered Wood Specialist: It is the preferred treatment for engineered products such as glulam beams. Because it can be applied as a water-based system with low water uptake (using processes like TRU-CORE®), it penetrates deeply into glue lines without compromising the structural stability of the engineered layers.
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Non-Corrosive: Unlike ACQ or CCA, Azole Clear treatments are generally non-corrosive to fasteners. While you should still use galvanized or stainless steel for outdoor durability, you don’t have the same high risk of “chemical corrosion” that heavy-copper treatments can cause.
Best Uses for Azole Clear
Because it provides high-level protection without altering the wood’s look, you will typically find it used for:
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External Cladding & Fascia: Where a modern, natural wood look is required.
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Decorative Pergolas: Where the timber is visible and will be stained or left clear.
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Window and Door Reveals: Its dimensional stability makes it perfect for joinery.
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Residential Decking Sub-frames: Especially when the deck is visible from below and the homeowner wants a cleaner look than green-tinted pine.
A Note on Maintenance
While Azole Clear protects against termites and rot, it does not provide a permanent barrier against UV rays or moisture absorption.
Pro Tip: To prevent the timber from silvering or “checking” (small surface cracks), Azole Clear treated timber should always be finished with a high-quality UV-protective coating or oil (like Cutek Extreme) shortly after installation.
Because Azole Clear is a “natural” treatment, the timber is protected from rot and termites, but it remains vulnerable to UV degradation (silvering) and moisture movement (cracking/warping). Using a penetrating oil like Cutek Extreme is the industry-recommended way to manage this.
Maintenance Schedule for Azole-Treated Victorian Ash
1. The Importance of Pre-Coating
Victorian Ash is a beautiful but “reactive” hardwood, meaning it moves significantly with changes in humidity.
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The Rule: Always coat all six sides (front, back, edges, and ends) before the boards are nailed or screwed down.
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The Result: This creates a uniform seal, preventing the “cupping” effect that happens when the front of a board dries faster than the back.
2. Choosing Your Look: Colourtone vs. Clear
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For a Natural Look: Use Cutek Extreme “Clear.” The Azole treatment will prevent rot, but the sun will naturally turn the Victorian Ash into a sophisticated silver-grey over 12–24 months. You still need to re-oil every few years to keep the wood stable and prevent cracks.
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To Maintain the “Fresh Cut” Look: Add a Cutek Colourtone (such as “Honey Oak” or “Clear Ash”) to the oil. The added pigment acts as “sunscreen” for the wood, blocking UV rays and preserving the original blonde/straw tones.
3. Cleaning Before Re-coating
Never apply new oil over dirty timber.
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Use a specialized cleaner like Cutek Restore if the timber has already greyed or has water stains.
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Use Cutek Quickclean for regular maintenance if the timber is still in good condition.
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Warning: Avoid high-pressure washers, as they can “fuzz” the grain of Victorian Ash, making it feel rough and absorbent.
Pro Tip: The “Water Test”
Not sure if it’s time to re-coat? Splash some water on your cladding.
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If the water beads up and rolls off, your protection is still active.
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If the water soaks in and leaves a dark patch, the wood fibers are exposed and it’s time for a maintenance coat.