Retaining Wall Checklist - Free Download

Measure the retained height, not just the wall face

WA's 0.5 m building-permit exemption is measured on ground retained, not wall face height - get this wrong and you may skip a permit you actually need.

Check if the wall is associated with other building work

A wall tied to a driveway, patio or other structure can need a permit at any height, regardless of the 0.5 m threshold.

Confirm the boundary and adjoining-land position

A wall that affects or protects adjoining land, or sits on a boundary or dividing fence, can trigger permit requirements independent of height.

Ask your council about local planning requirements

Building permit and planning approval are separate WA tests - a permit-exempt wall can still need development approval under your local R-Codes.

Get a soil read for your specific block, not the suburb average

Perth soils vary block to block - Swan Coastal Plain sand, Darling Scarp rock and gravel, and Guildford Formation clay all need different footing approaches.

Ask what drainage is included

Ag-drain, gravel and geofabric (a fabric layer that keeps soil separate from the drainage gravel so it does not clog) behind the wall are the structural detail that prevents failure through Perth's wet winters - confirm it is priced in, not an extra.

Confirm whether engineering is needed

Walls over the 0.5 m threshold generally need AS 4678 structural design and a Certificate of Design Compliance (BA3) - budget for this before comparing quotes.

Ask about excavation risk if you're near the coast

Tamala limestone can sit at shallow, variable depth under Perth's sandy suburbs - hitting rock early is a real cost driver, not a rare surprise.

Get the quote in writing, itemised

A verbal estimate is not a fixed price - a written quote protects you if site conditions turn out different from the initial assessment.

Ask what's excluded from the headline price

GST, excavation, drainage and engineering are commonly excluded from a per-square-metre price - confirm the real all-in cost.

Check access for machinery before work starts

Narrow side access or a steep hills block can mean hand-dig sections, which changes both cost and timeline if not planned upfront.

Ask about the wall's expected service life

Timber sleeper walls have a shorter in-ground life than concrete or limestone - factor this into a like-for-like comparison, not just upfront price.

Confirm who holds responsibility for the finished wall

Understand what workmanship assurance applies to the finished job before work begins, not after a fault appears.

Photograph the site before work begins

A dated record of existing conditions (fences, paving, neighbouring structures) protects you if a dispute arises about pre-existing damage.