Home / Wood Compare / ThermoWood Birch Thermo-D vs Thermally Modified Oak
Professional Comparison · Source-attributed engineering data · Updated 19 July 2026
ThermoWood Birch Thermo-D VS Thermally Modified Oak
Which wood is better for your project? Scores are computed from the verified figures on each species page — how we score.
Verdict: near-tie. The right choice depends on the application — see winner by category below.
🥇
ThermoWood Birch Thermo-D
62/100 Library Score
🪵Hardwood🌧Outdoor💧Moisture Stable
- Stronger in bending (MOR 95.0 vs 78.0 MPa)
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Thermally Modified Oak
61/100 Library Score
🪵Hardwood🌧Outdoor💧Moisture Stable
- More durable (Class 1)
- Solid choice where its profile fits the project
Visual comparison
ThermoWood Birch Thermo-DThermally Modified Oak
Winner by category
There isn't one universally best wood — there's a best wood for each purpose.
| Category | Winner |
|---|---|
| Durability | Thermally Modified Oak |
| Stability | Tie |
| Hardness | ThermoWood Birch Thermo-D |
| Strength (MOR) | ThermoWood Birch Thermo-D |
| Stiffness (MOE) | ThermoWood Birch Thermo-D |
| Flame spread | Tie |
| Machining ease | Tie |
| Lightness | ThermoWood Birch Thermo-D |
Engineering data
| Property | ThermoWood Birch Thermo-D | Thermally Modified Oak |
|---|---|---|
| Janka Hardness | 1210UNV lbf | 1120UNV lbf |
| Density | 0.62ITWA g/cm³ | 0.68ITWA g/cm³ |
| MOE | 12.0ITWA GPa | 11.0ITWA GPa |
| MOR | 95.0ITWA MPa | 78.0ITWA MPa |
| Durability | Class 2 Durable (treated) | Class 1 Very Durable (treated) |
| Stability | Good | Good |
| Fire (E84) | Not classified | Not classified |
| Radial Shrink | 1.6ITWA % | 1.8ITWA % |
| Tangential Shrink | 3ITWA % | 3.5ITWA % |
| T/R Ratio | 1.88 | 1.94 |
Figures carry the same source status as the species pages they come from — verified where cited, indicative where marked.
Best for
| Application | Recommended | Suitability |
|---|---|---|
| Outdoor decking / pergola | 🥇 Thermally Modified Oak | ★★★★☆ |
| Exterior cladding | 🥇 Thermally Modified Oak | ★★★★☆ |
| Flooring / wear surfaces | 🥇 ThermoWood Birch Thermo-D | ★★★☆☆ |
| Furniture / interior joinery | 🥇 ThermoWood Birch Thermo-D | ★★★☆☆ |
| Structural / load-bearing | 🥇 ThermoWood Birch Thermo-D | ★★★☆☆ |
| Sauna / wet interiors | 🥇 ThermoWood Birch Thermo-D | ★★★★☆ |
Advantages & limitations
ThermoWood Birch Thermo-D
Advantages relative to Thermally Modified Oak
- MOR is 95 MPa vs 78 MPa, about 22% higher
Limitations relative to Thermally Modified Oak
Thermally Modified Oak
Advantages relative to ThermoWood Birch Thermo-D
Limitations relative to ThermoWood Birch Thermo-D
- MOR is 78 MPa vs 95 MPa, about 18% lower
Recommendation
Choose ThermoWood Birch Thermo-D if…
- Exterior cladding, interior panelling and flooring, sauna benches and interiors where the higher bending strength matters in specification and the shared Class 2 thermally modified profile is the baseline
- Furniture and joinery where the birch grain and appearance are the aesthetic preference
Choose Thermally Modified Oak if…
- Exterior cladding, decking, interior flooring and panelling where the shared thermally modified profile matches the specification and the working properties are sufficient
- Joinery and feature surfaces where the oak grain and appearance are the aesthetic preference
Frequently asked questions
Which is more durable, ThermoWood Birch Thermo-D or Thermally Modified Oak?
Thermally Modified Oak — it carries the better EN 350 rating (Class 1 vs Class 2). Lower class numbers mean higher natural durability.
Which wood is better for outdoor use?
Thermally Modified Oak — outdoor performance combines decay durability with dimensional stability, and it leads on that combination.
Is ThermoWood Birch Thermo-D harder than Thermally Modified Oak?
Yes — Janka 1210 lbf vs 1120 lbf.
How we score. Scores shown are percentile ranks within our library, weighted towards durability and dimensional stability. They shortlist; they do not decide. Full weighting and what it excludes.