When designing a custom backyard sauna, every detail matters—from heat output and ambient lighting down to the timber lining the interior walls, ceiling, and benches.
For decades, Western Red Cedar has been the regional default. However, as modern sauna architecture evolves toward higher performance, longevity, and cleaner aesthetics, Imbue thermally modified wood has emerged as a premium alternative material for interior cladding and benching.
If you are looking to build an outdoor sanctuary that holds its structural integrity through thousands of high-heat steam cycles, stays comfortable to the touch, and eliminates common timber headaches, here is why Imbue outperforms traditional options.
Choosing the Right Timber for Sauna Walls & Benches
This process permanently alters the cellular structure of the wood:
Hemicellulose breaks down: Eliminating the organic sugars that fungi, rot, and mold feed on.
Moisture capacity drops dramatically: Water absorption is reduced by up to 50%, creating a hydrophobic barrier.
Cell structure locks: Internal stress points are released, preventing the timber from warping, cupping, or twisting over time.
The result is a lightweight, incredibly stable wood with rich, uniform tones that naturally resists decay and thermal transfer—without any synthetic additives or off-gassing.
Imbue vs. Western Red Cedar: A Direct Comparison
| Feature / Metric | Western Red Cedar (WRC) | Imbue Thermally Modified Wood |
|---|---|---|
| Dimensional Stability | Prone to expansion, contraction, cupping, and tongue-and-groove gaps. | Exceptional stability. Up to 50% less movement than traditional cedar. |
| Surface Finish & Longevity | Even when fine-sanded, WRC can raise grain and splinter over time due to moisture cycles. | Fine Sanded & Splinter-Free. Hydrophobic structure prevents raised grain and keeps bench surfaces silky smooth. |
| Resin & Sap Bleeding | Natural resins can seep out at high heat, leaving sticky spots on walls and benches. | 100% Resin-free. High processing temperatures vaporize all sap and pitch pockets. |
| Surface Temperature | Absorbs heat quickly; often requires towels on bare skin to avoid discomfort. | Stays cooler to the touch. Lower thermal conductivity keeps benching comfortable. |
| Moisture Resistance | Moderately porous; prone to sweat watermarks and dark staining over time. | Hydrophobic. Water beads off the surface, preventing deep moisture absorption. |
| Chemical Additives | 100% natural. | 100% natural. Heat and steam treated only—no toxins or synthetic seals. |
| Cost Comparison | $$$ | $$$ |
| Aesthetic Aging | Variable color variation board-to-board; can soften and turn grey over time. | Deep tone consistency. Warm amber-brown hues throughout the core of the board. |
Key Reasons Imbue Outperforms Western Red Cedar
1. Benches Stay Cooler and Smoother to Bare Skin
2. Zero Resin Weeping or Sticky Spots
Western Red Cedar naturally contains pitch pockets. In hot saunas (especially above 80°C), cedar can bleed sticky resin onto wall cladding or seating areas. Imbue’s thermal modification process completely bakes out all natural resins and volatile compounds during manufacturing, ensuring a permanently clean surface.
3. Ultimate Structural Stability for Wall Cladding
Every time steam (löyly) hits a sauna interior, humidity spikes. Standard cedar panels expand and contract with each heat cycle, eventually pulling away from fasteners and causing gaps between tongue-and-groove boards. Imbue’s locked cellular structure eliminates internal movement, keeping your wall panels tight and benches rock-solid for decades.
4. Resistance to Staining and Mold Growth
Sweat, splashing water, and high humidity make untreated cedar susceptible to dark watermarks and eventual mildew along lower wall panels and bench framing. Imbue’s hydrophobic structure means moisture sits on the surface rather than soaking into the grain, making post-sauna maintenance effortless.
Suggested Profiles:
TG27 180x17.5
170.5mm cover
TG27 136.5x17.5
127mm cover
Imbue™ Key Features:
1. Heat tempered for durability, stability, and long-term performance.
2. Durability Class 1 (EN350) and Class 2 (AS5604) – above ground.
3. 96.5% dimensional stability.
4. High grade quality timber with mainly clear faces and minimal knots.
5. 15-Year Warranty Against Rot*
*Imbue Cladding and Screening Maintenance Guide
*Imbue Radiata Global Warranty
6. FSC® certified timber from responsibly managed plantations.
7. Light weight and easy to install.
8. Easy to maintain and lower maintenance costs over its lifespan.
9. Naturally chocolate brown, will silver with age unless finishes are applied.
10. Accepts most finishes including water and oil borne stains and paints.
Frequently Asked Questions
Is thermally modified wood safe to use in a high-heat sauna?
Yes. The process uses only heat and steam, creating zero toxic off-gassing when exposed to high heat.
Do you need to coat, seal, or oil Imbue timber inside a sauna?
No. The wood should remain raw. Its natural hydrophobic structure provides built-in durability while allowing the timber to breathe and stay cool to the touch.
What care and maintenance is required for Imbue sauna wood?
Maintenance is exceptionally light. Simply wipe down benches with a damp cloth after each session and leave the door open to air out. For periodic cleaning, use warm water and a mild, sauna-safe soap; any accidental surface marks can be easily refreshed with a quick, light sanding.
Crafting a Modern Outdoor Retreat
Beyond performance, Imbue™ brings a refined aesthetic to modern backyard saunas. The natural baking process deepens the wood tone through the entire core—not just on the surface—giving every wall panel and bench slat a rich, warm finish that elevates the entire build.
Thermally modified flatsawn wood for siding, soffit, panelling & decking
Imbue™ is flatsawn Radiata pine, thermally modified to enhance its natural durability and stability, creating sustainable materials built to last.
This heat-treated wood cladding is available in both Imbue™ and Imbue™ Light, each with a curated collection of program colours selected by Fisher’s coating specialists.
