What is the difference between C24 and C16 timber?

C24 and C16 are strength classes defined in EN 338, where the number represents the characteristic bending strength in N/mm². C24 timber has 50% higher bending strength (24 vs 16 N/mm²), 22% higher stiffness (11,000 vs 9,000 N/mm² mean MOE), and higher density (420 vs 370 kg/m³ characteristic).

C24 and C16 are strength classes defined in EN 338, where the number represents the characteristic bending strength in N/mm². C24 timber has 50% higher bending strength (24 vs 16 N/mm²), 22% higher stiffness (11,000 vs 9,000 N/mm² mean MOE), and higher density (420 vs 370 kg/m³ characteristic). C24 is the standard structural grade across most of Europe, while C16 is used for non-critical applications, temporary works, and where economy is prioritised over performance. The visual difference is that C24 permits fewer and smaller knots than C16.

Why this matters

This question relates to European Timber Grades Explained: Nordic, German & British Systems, which covers the broader topic in detail. Understanding this specific aspect helps architects, builders, and timber dealers make informed specification decisions.

For full context and additional technical detail, see our comprehensive guide:

→ European Timber Grades Explained: Nordic, German & British Systems

Related questions

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About this answer

This answer is part of the PuurModulair Knowledge Base — comprehensive timber specification guidance for architects, builders, and dealers across the UK, EU, and Scandinavia.