For generations, teak has been the gold standard for outdoor and marine timber - beautiful, stable and almost indestructible. But it is expensive, increasingly hard to source responsibly, and the price keeps climbing. Thermally modified wood now offers much of the same performance from sustainable species. So which should you actually choose? It depends on three things: budget, lifespan and looks.
The honest comparison
Let us put the two side by side on the factors that decide most projects. These are general figures - exact numbers vary by species and treatment grade - but they capture the real picture.
| Factor | Teak | Thermowood (Thermo-D) |
|---|---|---|
| Natural durability | Excellent (Class 1) | Very good (Class 1–2) |
| Dimensional stability | Excellent | Excellent |
| Bending strength | High | Reduced by treatment |
| Cost | Very high | Moderate |
| Sustainability | Concerns over sourcing | Strong (fast-grown species) |
| Natural oils | Yes (self-protecting) | No (oils driven off) |
| Appearance | Golden brown, ages silver | Rich brown, ages silver |
Where teak still wins
Teak earns its price in specific situations. Its natural oils make it self-protecting and superb in marine environments - boat decks remain a teak stronghold for good reason. It also keeps its full structural strength, so where a timber must look beautiful and carry load, teak does both. And for ultra-premium furniture where provenance and the unmistakable teak grain are part of the value, there is no substitute.
For boat building and constant saltwater immersion, teak's natural oils still give it an edge. Thermowood performs well outdoors but was not designed to replace teak in demanding marine decking.
Where thermowood wins
For the vast majority of architectural uses - cladding, decking, screens, garden structures, exterior joinery - thermowood delivers comparable stability and durability at a far lower cost, with a much cleaner sustainability story. You are buying fast-grown pine or ash that has been upgraded by heat, not a slow-growing tropical hardwood shipped across the world.
The decisive factor is usually lifetime cost. Teak's higher price can be justified over decades of service, but thermowood's combination of long service life and lower upfront cost often wins on a pure cost-per-year basis - especially for large cladding or decking areas where the material quantity is significant.
A simple way to decide
Work through these questions in order:
- Is it for marine or constant immersion use? Choose teak.
- Does the timber carry structural load while exposed? Lean towards teak, or engineer around thermowood's reduced strength.
- Is it premium visible furniture where teak grain is the point? Choose teak.
- Is it cladding, decking, screening or exterior joinery on a budget, with sustainability mattering? Choose thermowood - this is its sweet spot.
The verdict
Teak is not obsolete - it remains the right choice for marine work, exposed structural timber and the most premium furniture. But for everyday architectural timber, thermally modified wood has closed the performance gap to the point where paying teak prices is hard to justify. For most projects in 2026, thermowood is the smarter specification. The one reliable way to be sure for your job is to compare lifetime cost with real numbers rather than reaching for teak out of habit.