Moisture content and durability

Moisture content and durability

Date Published

28 August 2022

Document Type




The moisture content in trees decreases once felled. While growing, the moisture content can be 96% (Green), whereas when dry it can go to 12%.

Key Information

Loss of moisture from the cell walls will reduce the girth of the tree substantially in some species, slightly in others.

To prevent major shrinkage and possibly change of shape in use the wood is usually dried down before it is converted into a building material.

If wood is to be used outside and therefore exposed directly to rain, sunlight and wind it should either have sufficient natural durability or be treated in some way to enhance its durability and to achieve an adequate service life.

Case studies

The GlaxoSmithKline (GSK) Carbon Neutral Laboratory for Sustainable Chemistry was designed as an exemplar of sustainability in design, construction and choice of materials, and one which would be carbon neutral over its 25 year lifetime.

Simpson & Brown Architects has designed a new visitor centre for English Heritage, using timber to create its principal space, a light-filled arcaded hall of tall glulam arches, reflecting the characteristic columns and pointed arches of the Gothic ruins.