Western Red Cedar VS Thermally Modified Western Red Cedar
- Stronger in bending (MOR 51.7 vs 45.0 MPa)
- Close second across most categories
- Solid choice where its profile fits the project
Visual comparison
Winner by category
There isn't one universally best wood — there's a best wood for each purpose.
| Category | Winner |
|---|---|
| Durability | Tie |
| Stability | Tie |
| Hardness | Tie |
| Strength (MOR) | Tie |
| Stiffness (MOE) | Western Red Cedar |
| Flame spread | Tie |
| Machining ease | Tie |
| Lightness | Tie |
Engineering data
| Property | Western Red Cedar | Thermally Modified Western Red Cedar |
|---|---|---|
| Janka Hardness | 350WD lbf | 350UNV lbf |
| Density | 0.32FPL g/cm³ | 0.38ITWA g/cm³ |
| MOE | 7.7FPL GPa | 7.5ITWA GPa |
| MOR | 51.7FPL MPa | 45.0ITWA MPa |
| Durability | Class 2 Durable | Class 2 Durable (treated) |
| Stability | Moderate | Moderate |
| Fire (E84) | Class C indicative | Not classified |
| Radial Shrink | 2.4WD % | 1ITWA % |
| Tangential Shrink | 5WD % | 2ITWA % |
| T/R Ratio | 2.08 | 2.0 |
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 | 🥇 Western Red Cedar | ★★★☆☆ |
| Exterior cladding | 🥇 Western Red Cedar | ★★★★☆ |
| Flooring / wear surfaces | 🥇 Western Red Cedar | ★☆☆☆☆ |
| Furniture / interior joinery | 🥇 Western Red Cedar | ★★★★☆ |
| Structural / load-bearing | 🥇 Western Red Cedar | ☆☆☆☆☆ |
Advantages & limitations
Western Red Cedar
Advantages relative to Thermally Modified Western Red Cedar
- MOR is 51.7 MPa vs 45 MPa, about 15% higher — thermal modification typically reduces bending strength
- Fire (E84) is Class C classified vs unclassified — has a specified rating for building-code purposes
Limitations relative to Thermally Modified Western Red Cedar
- Radial shrinkage 2.4% vs 1.0% and tangential 5.0% vs 2.0% — much greater movement in service
Thermally Modified Western Red Cedar
Advantages relative to Western Red Cedar
- Radial shrinkage 1.0% vs 2.4% and tangential 2.0% vs 5.0% — much less movement in service
Limitations relative to Western Red Cedar
- MOR is 45 MPa vs 51.7 MPa, about 13% lower
- Fire (E84) is unclassified — no specified rating for building-code purposes
Recommendation
Choose Western Red Cedar if…
- The end use is shingles, shakes, boat/ship building, or poles — uses where thermal modification is not documented
- Building code requires a specified fire class (Class C)
Choose Thermally Modified Western Red Cedar if…
- Dimensional stability is critical — cladding, rain screens, or soffits where seasonal movement between profiles shows
- The application is sauna interiors or garden structures documented for the modified product
Frequently asked questions
Which is more durable, Western Red Cedar or Thermally Modified Western Red Cedar?
Neither — both carry the same EN 350 rating (Class 2, Durable). For outdoor work the separation is movement, not decay: Thermally Modified Western Red Cedar moves 2.0% tangentially against 5.0%, which decides board width and fixing spacing more than the durability class does.
Which wood is better for outdoor use?
Both are EN 350 Class 2, and tangential movement runs 5.0% for Western Red Cedar against 2.0% for Thermally Modified Western Red Cedar — close enough that decay resistance will not choose between them, and Thermally Modified Western Red Cedar holds its dimension marginally better. Hardness is effectively level (350 vs 350 lbf), so choose on weight.
Is Western Red Cedar harder than Thermally Modified Western Red Cedar?
They measure the same on the Janka scale (350 lbf each) — effectively equal in surface hardness.