Target design life of 5 years:

Environment

• 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.

Examples

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