Timber Sleeper Retaining Walls

Timber sleeper walls are the cheapest way to retain a bank and they are what most people picture when they think of a retaining wall. We build them, and we would rather tell you what you are buying than sell you one on price alone.

The honest position on timber in this climate

Timber in ground contact in Far North Queensland has a hard life. It is wet for months at a time, the ground rarely dries out fully, and termite pressure here is among the highest in the country. A timber sleeper wall that would give thirty years in a dry southern climate will not do that here, and any operator who tells you otherwise is either inexperienced or hoping you will not be around to notice.

That is not an argument against ever using timber. It is an argument for using it where the consequence of eventual replacement is small.

Where timber genuinely makes sense

Low garden walls where the retained height is modest and nothing structural depends on it. Terraced planting beds. Walls in a setting where the timber is doing aesthetic work, in a native or bush garden where concrete would read as wrong. Temporary or staged work where a permanent wall is planned later. Places where access is so tight that the weight of concrete sleepers is genuinely prohibitive.

Where it does not make sense: holding up a driveway, supporting anything structural, anywhere the wall is tall, or anywhere replacing it later would mean dismantling something built on top of it. In those cases the money saved now is borrowed against a much larger job later, and we will say so.

What we specify if you go ahead

Hardwood sleepers or H4 treated pine rated for in-ground contact, never a lower treatment level regardless of what a supplier is willing to sell. Galvanised steel posts rather than timber posts wherever the height allows it, because the post is what fails first and steel posts remove that failure mode entirely while keeping the timber face.

Sleepers sit behind the posts rather than being fixed through the face where the design permits, so soil pressure pushes them against the posts rather than onto the fixings.

The drainage does not change

A timber wall gets exactly the same treatment behind it as a concrete one: subsoil drain to a real outlet, free-draining backfill, filter fabric. Timber walls are often built without any of it on the assumption that gaps between the sleepers will let water through, and they will, along with the fines from the soil behind, which is how a timber wall ends up with a hollow behind it and a lawn that sinks.

If you want the comparison in full, read concrete or timber sleepers. Otherwise call 0468 066 055 and we will tell you honestly which one your job wants.