Moisture in timber

TRADA image

One of the most important factors affecting the performance and properties of wood is its moisture content. The amount of water present in wood can affect its weight, strength, workability, susceptibility to biological attack and dimensional stability in a particular end use.

We estimate that over 80% of the in-service problems associated with wood are in some way related to its moisture content. The importance of the interaction between water and wood cannot be understated and, if not properly understood and taken into consideration, can result in the need for expensive remedial measures.

This Wood Information Sheet provides basic information for the specifier and user on the facts and importance of the moisture content of wood. It considers drying, shrinkage and movement, including movement values for some common species, and also looks at measuring moisture content, particularly the use of moisture meters.


  • Water and wood
  • Reasons for drying timber
  • Principles of timber drying
  • Measuring moisture content
  • Specifying moisture content
  • Care of dried timber

This Wood Information Sheet was revised in June 2016. The graph in Figure 3 was updated and the section on shrinkage was amended to reflect the changes. A moisture content control plan was also added in the specifying moisture content section.

This Wood Information Sheet was reviewed in February 2017 and minor corrections were made to the references section.

Suggested Reading

Making the grade - A guide to appearance grading UK grown hardwood timbernavigation-arrow

This guide details appearance grades applicable to hardwood planks and boards from trees grown in the UK. It broadly follows the grading criteria set out in EN 975 - 1 but with modifications to take account of the timber availability, species, characteristics and production methods found in the UK.

01/01/2005 |  Info from other organisation  

Timbers - their properties and usesnavigation-arrow

This sheet sets out the properties of 140 timber species commonly used in the UK. A brief overview of the properties a specifier should consider is followed by a reference table that can be used to help with species selection or to determine species with comparable properties when alternatives are...

05/01/2015 |  Wood Information Sheet  

Structural use of hardwoodsnavigation-arrow

Although the vast majority of structural timber in the UK is softwood, there is a significant interest in hardwoods from both temperate and tropical regions for structural applications. When using hardwoods in structures, the specifier may need to take more interest in the species, its origin and its moisture condition...

11/01/2017 |  Wood Information Sheet