This infographic distills essential factors that influence how long European oak lasts and how its value is assessed in structural and furniture contexts, including strength classifications, grading rules, and durability expectations.
Key takeaways
- European oak structural strength class is typically D30 when tested around ~12% moisture content, under BS EN 338/BS EN 1912.
- In Europe, hardwood strength classes cover D24, D30, D40, D50, D60, D70; oak is commonly D24–D30 for structural use.
- In the UK market, most structural oak is D24 or D30; D40 is technically possible but rare and usually not required.
- UK BS 5756 visual grades for oak include TH1, TH2 (sections <20,000 mm²) and THA, THB (sections ≥20,000 mm²); THB often equates to D30 in many sections.
- A typical UK declaration lists Grade THB, strength class D30, durability Class 2 (heartwood), to BS EN 338 and BS EN 350.
- Durability classes per BS EN 350 use five categories; European oak heartwood is generally Class 2 (Durable).
Sources
- West & Sons — European oak strength class and moisture reference
- iWood — Understanding timber grading (hardwood strength classes)
- Ecochoice — Typical UK oak grades
- Hewins Oak — Structural graded oak; grading table
- Yandles — Declaration of conformity for graded oak
- BWF — Durability (BS EN 350) overview