How do I compare EPDs from different timber manufacturers?

To compare EPDs fairly, ensure: same functional unit (e.g., 1 m³ of sawn timber at specified moisture content), same declared modules (compare A1–A3 with A1–A3, not A1–A3 with A1–A5), same EN 15804 version (A1 vs A2 — biogenic carbon reporting differs significantly), same product type (sawn timber vs glulam vs CLT have different impacts), and same system boundaries. Also check the background database used (Ecoinvent, GaBi, etc.) as this affects results.

To compare EPDs fairly, ensure: same functional unit (e.g., 1 m³ of sawn timber at specified moisture content), same declared modules (compare A1–A3 with A1–A3, not A1–A3 with A1–A5), same EN 15804 version (A1 vs A2 — biogenic carbon reporting differs significantly), same product type (sawn timber vs glulam vs CLT have different impacts), and same system boundaries. Also check the background database used (Ecoinvent, GaBi, etc.) as this affects results. Generic/industry-average EPDs are useful for early design but manufacturer-specific EPDs are more accurate for final specification.

Why this matters

This question relates to EPD (Environmental Product Declaration) for Timber: How to Read It, 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:

→ EPD (Environmental Product Declaration) for Timber: How to Read It

Related questions

• What is an EPD for timber?
• What lifecycle stages does a timber EPD cover?
• How is biogenic carbon reported in timber EPDs?

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.