Module: Timber as a material Unit: Moisture content and durability

Module: Timber as a material Unit: Moisture content and durability

Date Published

28 August 2022

Document Type

Category

Author

TRADA
Summary

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

Oasis Farm Waterloo is an urban farm, tucked away in the heart of London, next to Waterloo Station, just to the south of Westminster Bridge and the Houses of Parliament.

The walkway is the latest project for the Arboretum designed by Glenn Howells Architects.