High-Performance Materials for High-Performance Homes
How Arbor Wood Co. Thermowood® Elevates High-Performance and Passive Home Design
Building the Future of Sustainable Living
As architects, builders, and homeowners strive to create more sustainable, energy-efficient, and durable homes, attention has shifted beyond insulation and airtight envelopes — to the materials that make up the building itself. One material leading that evolution is thermally modified wood, and Arbor Wood Co. is at the forefront of its domestic production. With unmatched stability, longevity, and environmental integrity, Arbor Wood Co.’s products are redefining how natural wood performs in high-performance and Passive House construction.
What Is Thermally Modified Wood?
Thermally modified wood undergoes a specialized heat and steam process — without chemicals — that transforms the wood at the cellular level.
At Arbor Wood Co., this process involves:
Careful heating and drying to remove moisture from the fibers of the wood.
High-temperature modification in a low-oxygen environment, which breaks down sugars that attract fungi and moisture that can lead to rot and fungal decay.
Re-conditioning with steam to bring the moisture content back to a balanced 4–6%.
The result? A wood that is dimensionally stable, highly durable, moisture-resistant, and rich in color — all while remaining 100% natural.
Why Thermally Modified Wood Matters in High-Performance Design
Passive and high-performance homes are built around principles of airtightness, thermal efficiency, and material longevity. Every product must work together to create an envelope that is strong, stable, and efficient over decades.
Here’s how Arbor Wood Co. fits into that equation:
Dimensional Stability - Up to 60% less expansion and contraction keeps siding and cladding joints tight, preserving the building’s air and moisture barriers.
Moisture Resistance - Naturally repels water and resists decay — critical for maintaining the integrity of airtight envelopes and rainscreen systems.
Low Equilibrium Moisture (4–6%) - Drier wood reduces thermal bridging and helps maintain consistent insulation performance.
Chemical-Free & Domestic - Supports healthy indoor air quality and sustainability goals, aligning with LEED, WELL, and Passive House standards.
Durability & Beauty - A natural wood aesthetic with decades of performance and minimal maintenance requirements.
Applications in Passive and High-Performance Homes
1. Exterior Cladding and Siding
Use Arbor Wood Co. thermally modified cladding as part of a ventilated rainscreen assembly. Its moisture resistance protects insulation and air barriers, while its stability ensures long-term performance with minimal maintenance.
2. Decking and Outdoor Living
In Passive House projects, outdoor living spaces often extend the home’s usable area. Arbor Wood decking resists warping, cracking, and rot — delivering long-lasting performance in all climates.
3. Window and Door Surrounds
Because thermally modified wood resists swelling and shrinking, it’s ideal for trim and casings that must maintain tight seals to prevent air leakage — a cornerstone of Passive House construction.
4. Interior Finishes
Beyond the envelope, thermally modified paneling, flooring, and ceiling treatments bring natural warmth to high-performance interiors — without introducing VOCs or chemicals.
The Science of Stability and Efficiency
Thermally modified wood’s reduced moisture absorption improves not only its lifespan but also the performance of adjacent materials. Drier assemblies mean fewer thermal bridges, less condensation, and better control of indoor humidity — all vital to Passive House standards. By maintaining its shape and density over time, Arbor Wood Co. helps prevent cracks, gaps, and thermal leaks that would otherwise degrade a building’s efficiency.
Sustainability at Its Core
Sourcing and production are as important as performance. Arbor Wood Co. uses responsibly harvested, domestic hardwoods and softwoods, modified through a chemical-free process that emits no harmful byproducts. This approach minimizes embodied carbon while maximizing material life — key metrics for sustainable certification and life-cycle performance.
Real-World Benefits
Extended material lifespan — reducing maintenance, refinishing, and replacement costs.
Lower embodied carbon through renewable sourcing and long-term durability.
Healthier indoor air quality thanks to a natural, non-toxic process.
Improved aesthetics with rich, through-colored wood tones that gracefully weather or can be finished for a maintained look.
Building Better with Arbor Wood Co.
For architects, designers, and builders focused on performance, beauty, and sustainability, Arbor Wood Co. thermally modified wood offers the perfect balance of all three. Whether used in rainscreen cladding, decking, or high-precision detailing, it elevates the integrity of modern sustainable construction.
Learn more about how Arbor Wood Co. can support your next high-performance project