Best decking timber for wet, shaded blocks

01

Start with durability class, not the name

Australian hardwoods are graded for durability above and below ground. For exposed work in the Ranges you want a high above-ground durability class, and anything in ground contact needs to be rated or treated for it.

Species availability shifts constantly. Rather than fixating on one name, ask what your supplier has in the right class, seasoned and straight. Merbau, spotted gum and blackbutt are all common choices; composite boards suit some shaded, low-maintenance situations.

02

Ventilation beats species every time

The most durable board in the country will fail if it sits on a damp, unventilated frame that never dries. Air movement under and behind timber is the most effective longevity measure available.

Keep clearances to ground, avoid trapping leaf litter, and never sit timber directly on concrete without a break.

03

Fixings and finishes

Use stainless fixings anywhere exposed. Rust bleeding down a face is both ugly and a sign the fixing is failing internally.

Choose oil over film-forming coatings on horizontal surfaces. Oil wears back gracefully and can be refreshed; a peeling film has to be stripped.

04

Plan for movement

Timber in this climate takes on and gives up moisture constantly. Set gaps to allow it, fix boards so they can move, and expect some checking on wide faces. That is timber behaving normally, not a defect.