Target design life of 5 years

Target design life of 5 years:


  • Fully protected from and/or exposed to the weather or other dampness.
  • Clear of the ground, well drained and/or ventilated and with free air circulation.
  • Non-structural (not load-bearing or not supporting in function).

Conditions of use

  • C and H codes—none are applicable for 5-year-TDL applications.
  • Unless otherwise specified for appearance reasons, sawn timber may contain untreated non-lyctine-susceptible sapwood, provided that the combination of such sapwood and any associated wane does not exceed the wane limits permitted by the relevant Australian Standard.

Treatment (other than for termites)

  • Any lyctine-susceptible sapwood must be treated to minimum H1 level in accordance with the provisions of AS 1604.

Termite protection

  • Where termite-resistant timber is required in accordance with the BCA, it may be either:
    • timber classified as naturally termite resistant (R) or
    • timber classified as not resistant (NR) but that has been treated to minimum H2 level in accordance with the provisions of AS 1604.


Building members with a 5-year-TDL are listed in the guide: Building members.

Used in field: