The Importance of Specifying Thermowood®


WHY IT MATTERS

As thermally modified wood continues to gain traction in architecture, design, and high-performance construction, more suppliers are entering the market offering “thermally modified” products. But not all modified wood is created equal. In fact, choosing the wrong supplier can lead to performance issues, warranty problems, and costly callbacks — especially for exterior cladding and decking applications where durability is non-negotiable.

That’s why partnering with an official ThermoWood® provider is so important. ThermoWood® isn’t just a category; it’s a global standard of excellence. Backed by decades of research and governed by the International ThermoWood Association (ITWA), the ThermoWood® process delivers proven performance, documented consistency, and a level of quality control that generic thermally modified wood simply can’t match.

Here’s what sets an official ThermoWood® provider apart — and why it matters for every specifier, builder, and project owner.

1. Proven, Certified Performance

ThermoWood® is produced using a precise, scientifically validated process developed in Finland and now available in North America. This method controls heat, oxygen levels, and moisture with extreme accuracy, ensuring the wood reaches the correct chemical transformation for improved stability and durability.

When working with a certified provider, you can expect:

  • Consistent material modification levels

  • Documented dimensional stability

  • Predictable long-term performance

  • Reduced risk of cupping, warping, or checking

These assurances are backed by third-party research and decades of real-world application — not guesswork.

2. Accountability Through Standards & Testing

Official ThermoWood® producers follow strict quality-control standards and ongoing compliance testing. That includes:

  • Regular audits

  • Verified process temperatures and durations

  • Product classification (e.g., Thermo-D)

  • Performance testing against European and international benchmarks

This ensures every board — not just every batch — aligns with the published performance claims. For architects and builders, that means less uncertainty and more confidence in what ends up on the façade or deck.

3. Sustainability You Can Document

ThermoWood® providers adhere to responsible sourcing policies that support sustainable forestry. Many suppliers also maintain PEFC or FSC certifications, ensuring material transparency from forest to finish.

For projects targeting:

  • LEED

  • WELL

  • Living Building Challenge

  • Local green-building standards

Working with an official ThermoWood® provider makes documentation easier and more defensible during submittals and reviews.

4. A Supply Chain You Can Trust

Working with a certified producer ensures:

  • Traceability: Every board can be traced back to its origin.

  • Predictability: You get consistent supply, reliable lead times, and stable product specs.

  • Support: You gain access to technical guidance, install best practices, and performance documentation.

When alternative suppliers imitate the process without the oversight, the risks fall on you — the specifier or builder — if things go wrong.

5. Long-Term Value for Your Projects

Thermally modified wood is an investment in the lifespan of a building. When done right, it offers decades of performance with minimal maintenance.

When done poorly, it can:

  • Fade unevenly

  • Fail prematurely

  • Compromise the building envelope

  • Lead to moisture issues and warranty disputes

Choosing an official ThermoWood® provider helps ensure that the material performs the way high-performance wood should — beautifully and reliably.

Why Many ARchitects & Designers Choose Arbor Wood Co.

As an official ThermoWood® producer, and the first and only ITWA member in the US, Arbor Wood Co. follows the exacting Finnish-developed process using domestically sourced timber. The result is a material that combines:

  • True Thermo-D and Thermo-S performance

  • Warm, refined aesthetics

  • Responsible sourcing

  • Reliable supply for projects of any scale

From contemporary commercial spaces to residential exteriors, designers choose Arbor Wood Co. for the confidence that comes with certified ThermoWood®.


Don’t Compromise on the Source

Thermally modified wood is only as good as the process behind it. With more look-alike materials appearing in the marketplace, the safest way to protect your project is to specify an official ThermoWood® provider — one who follows the standards, testing, and certification that give ThermoWood® its reputation.

Because when durability, stability, sustainability, and long-term performance matter, the source isn’t a detail — it’s the foundation.


Contact Our Team to Discuss Your Project
Andrew Ellingson