Hot Oil Treatment
Long-Lasting Beauty and Stability for Outdoor Wood
Naturally Durable Facade Wood, Enhanced with Linseed Oil
WTT’s hot-oil treatment is a specialized post-treatment process using hot linseed oil to elevate the performance of biocide-treated timber – ideal for cladding, siding, and other outdoor applications where longevity and aesthetics matter.
By integrating natural oils and pigments, the process results in a ready-to-use, color-stable product that can withstand the elements for 5 to 25 years without the need for repainting – depending on climate conditions.
How It Works
From Impregnation to Protection
After high-pressure biocide impregnation, the timber typically retains high moisture content. Instead of undergoing separate drying, the wood is transferred directly from the impregnation autoclave into a hot-oil autoclave, where the real transformation begins.
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Over 6–8 hours, the wood is gently dried to a final moisture content of 14–16%
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During this phase, hot linseed oil penetrates 1–2 mm into the surface of the wood
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The result is a sealed envelope effect that dramatically reduces moisture exchange and improves dimensional stability
This "moisture shield" minimizes seasonal expansion and contraction, reducing cracking and distortion over time – and dramatically extending the wood’s usable lifespan.
Proven Performance in Demanding Climates
WTT has over 20 years of experience with hot-oil treatment technology, and the solution has proven especially popular in Scandinavia, where rough weather demands durability. The market continues to grow rapidly – with annual growth rates around 30%, and increasing adoption in both the UK and Central Europe.
WTT supplies fully automated hot-oil treatment plants to leading wood treatment companies operating in this high-value niche, supporting them with cutting-edge technology and proven process expertise.
Primer Oil Cladding – The Smart Alternative
One of the key applications of hot-oil treatment is Primer Oil treated cladding wood – a premium alternative to untreated or conventionally treated materials. Independent tests show significantly reduced moisture fluctuations, even under harsh weather exposure.
Result?
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Fewer cracks
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Better dimensional stability
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Longer-lasting aesthetics
WTT Hot Oil Treatment – The natural choice for architects, builders, and manufacturers seeking sustainability, durability, and elegance.
Naturally Durable
Hot-oil treatment enhances facade wood for long life in outdoor conditions.
Infused Protection
Linseed oil penetrates the surface, shielding wood from moisture and decay.
Long-Term Color
Natural pigments provide a stable finish that resists fading for decades.
No Extra Drying
Wood moves directly from biocide impregnation to hot-oil treatment.
Sealed Surface
Creates a 1–2 mm oil barrier that reduces swelling, cracking, and distortion.
Stable Moisture
Dries to 14–16% moisture in just 6–8 hours for improved dimensional reliability.
Weather-Proven
Proven in Nordic weather – durable even in extreme outdoor exposure.
Growing Demand
Used across Europe with 30% annual growth in key treatment markets.
Better Cladding
Primer Oil-treated wood resists movement and holds its shape longer.
Trusted Tech
WTT supplies automated plants to top producers in the wood industry.
