Birch TMT (Thermally modified)
Heat-treated state
Heat-treated birch for cladding, saunas and damp interiors — much better dimensional stability and decay resistance, at the cost of brittleness.
Values for the TMT condition
Other Birch tempers and conditions
Birch is listed in 3 conditions; see the grade overview at Birch.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Baltic/Russian birch plywood, all-birch cross-banded veneers | Void-free 1.4 mm all-birch veneer panel for CNC jigs, laser cutting, cabinets and model work — near-isotropic in-plane, but glue lines dull tools. | — | 50 | — | — | 0.15 W/m·K |
Green / unseasoned | Freshly sawn wet stock for green turning, steam bending or veneer peeling — roughly half the dry strength and will shrink on drying. | — | 75 | 2 | — | 0.28 W/m·K |
TMTThis page Thermally modified | Heat-treated birch for cladding, saunas and damp interiors — much better dimensional stability and decay resistance, at the cost of brittleness. | — | — | 0.9 | — | 0.12 W/m·K |
What is Birch TMT?
Birch TMT is Birch heat treated to TMT — heat-treated birch for cladding, saunas and damp interiors — much better dimensional stability and decay resistance, at the cost of brittleness. Birch TMT has a tensile strength of 115 MPa (16.7 ksi), stronger than 100% of natural material grades. Elongation at break is 0.9% and the elastic modulus is 13 GPa (1.89 Msi). Birch TMT has a density of 0.6 g/cm³ (0.0217 lb/in³), lighter than 66% of natural material grades.
Advantages
- High service temperature — 120°C (248 °F), better than 79% of natural material grades
Birch TMT properties
Typical room-temperature values for Birch TMT; 10 are specific to this condition. Other listed values are Birch reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
Birch TMT has a density of 0.6 g/cm³ (0.0217 lb/in³), lighter than 66% of natural material grades.
Mechanical9
Birch TMT has a tensile strength of 115 MPa (16.7 ksi), stronger than 100% of natural material grades. Elongation at break is 0.9% and the elastic modulus is 13 GPa (1.89 Msi).
Thermal5
Birch TMT is rated for continuous service to 120°C (248 °F). It conducts heat at 0.12 W/m·K (0.0693 BTU/hr·ft·°F), worse than 70% of natural material grades. Thermal expansion is 4 µm/m·K (2.22 µin/in·°F).
Electrical2
Birch TMT is an electrical insulator with a dielectric strength of 2 kV/mm (50.8 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental1
Corrosion resistance is good (55/100), better than 69% of natural material grades.
Sustainability4
Producing a kilogram of Birch TMT takes about 11 MJ of energy and emits 0.45 kg of CO₂ — more than 56% of natural material grades. Typical recycled content is 5%.
Manufacturability2
Birch TMT's machinability is very good (80/100, worse than 52% of natural material grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Birch TMT
Is Birch easy to machine?
Cuts, turns and routs cleanly with sharp carbide tooling; feed steadily and avoid dwell — the pale surface burns easily, and end grain benefits from a light climb-cut or scoring pass.
Can Birch be welded?
Not weldable; joined by PVA/urea-formaldehyde/epoxy adhesives or mechanical fasteners — birch glues exceptionally well, which is why it dominates plywood production.
Can Birch be formed, bent or molded?
Steam bends well when green or at high MC (typical bend radius ~6–10× thickness); veneer peels smoothly at 1.4 mm and cold-presses into curved laminations.
What surface finishes work on Birch?
Sands to a fine surface but blotches with penetrating stains — use a washcoat/conditioner or spray tone; takes clear lacquer, waterborne PU and paint very well. No natural decay resistance: seal or preservative-treat for any damp service.
Birch chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| celluloseoven-dry basis | 40 – 45 | 42 |
| hemicellulose (mainly glucuronoxylan)high xylan content typical of birch | 28 – 35 | 32 |
| ligninsyringyl-rich hardwood lignin | 18 – 22 | 20 |
| extractivesbetulin in bark, low in wood | 1.5 – 4 | 2.5 |
| ash | 0.2 – 0.6 | 0.35 |
Birch TMT — frequently asked
What is Birch TMT used for?
Birch TMT is typically used for furniture, turned parts, interior joinery, toys and veneer core. In short: best-gluing plywood veneer; tough, low-cost pale hardwood; stable interior joinery stock.
What is the tensile strength of Birch TMT?
Birch TMT has a typical tensile strength of 115 MPa (16.7 ksi) — stronger than 100% of natural material grades. Strength varies by condition: see the 3 listed tempers.
Is Birch TMT easy to machine?
Yes — machinability is rated very good (80/100, worse than 52% of natural material grades). Cuts, turns and routs cleanly with sharp carbide tooling; feed steadily and avoid dwell — the pale surface burns easily, and end grain benefits from a light climb-cut or scoring pass.
Can Birch TMT be welded?
Not weldable; joined by PVA/urea-formaldehyde/epoxy adhesives or mechanical fasteners — birch glues exceptionally well, which is why it dominates plywood production.
What surface finishes work on Birch TMT?
Sands to a fine surface but blotches with penetrating stains — use a washcoat/conditioner or spray tone; takes clear lacquer, waterborne PU and paint very well. No natural decay resistance: seal or preservative-treat for any damp service.
Can Birch TMT be formed, bent or molded?
Steam bends well when green or at high MC (typical bend radius ~6–10× thickness); veneer peels smoothly at 1.4 mm and cold-presses into curved laminations.
What is the maximum service temperature of Birch TMT?
Birch TMT is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Wood Handbook — Wood as an Engineering Material, FPL-GTR-190 — USDA Forest Products Laboratory (2021)
- EN 13556 — Round and sawn timber: nomenclature of timbers used in Europe (code BETU) — CEN (2003)
- EN 350 — Durability of wood and wood-based products — CEN (2016)
- CES EduPack / ICE v3 embodied energy and carbon data for sawn hardwood — Granta / University of Bath (2019)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.