What moisture content should I specify for structural timber?

For structural timber in enclosed buildings, specify a target moisture content of 18% ±2% at delivery, with a maximum of 20%. For timber that will be enclosed in insulated walls or floors, specify 16% ±2%.

For structural timber in enclosed buildings, specify a target moisture content of 18% ±2% at delivery, with a maximum of 20%. For timber that will be enclosed in insulated walls or floors, specify 16% ±2%. For joinery-grade timber, specify 10–14% depending on the end-use environment. Always state the measurement method (resistance meter to EN 13183-2) and sampling frequency in your specification.

Why this matters

This question relates to How to Write a Timber Specification for Construction Tenders, 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:

→ How to Write a Timber Specification for Construction Tenders

Related questions

• What should a timber specification include?
• How do I specify timber grade in a tender document?
• Should I specify FSC or PEFC certification?

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. All technical content is reviewed by qualified timber technologists before publication.