Timber Durability

Timber Durability

Timber durability is a measurement of how long certain species of timber would last if a 50mm x 50mm cross section was left in the ground unprotected.

An untreated oak beam, which is classed as 'durable' will last 15-25 years depending on environmental conditions.

The following scale of durability was outlined by TRADA, the Timber Research And Development Association.

Durability Class Designation Average timber service life Example Timber
5 Not durable less than 5 years American Ash
4 Slightly durable 5-10 years American Popular Tulipwood
3 Moderately durable 10-15 years American White Oak
2 Durable 15-25 years -
1 Very durable more than 25 years -

Kiln Dried Timber