Retaining Wall Checklist
Fourteen questions to work through before you start a Perth retaining wall project - compliance, material, drainage and quote checks in one place. All fourteen are set out in full on this page, free and with nothing to fill in first.
Retaining Walls Perth Checklist: Method and Sources
What this is: fourteen practical checks, not a generic to-do list - each one is grounded in the real WA building-permit rule (Building Regulations 2012 Schedule 4), AS 4678 engineering practice, and published Perth material cost data, not invented advice.
Sources: Building permit and BA3 certification items per wa.gov.au and Building Regulations 2012 (WA); cost and drainage items per the same sources cited on the cost calculator page.
- 01
Confirm your wall height including any retained fill or cut
The WA 0.5 m exemption is measured on ground retained, not just the visible wall face - get this number right first.
- 02
Check whether the wall is tied to other building work
A wall linked to a pool, driveway or extension can lose the exemption regardless of height.
- 03
Check whether the wall affects a boundary or dividing fence
Boundary-adjacent walls can trigger approval requirements even under 0.5 m.
- 04
Contact your local government to confirm permit requirements
Council wording and tiered-wall rules differ slightly across Perth - always confirm locally.
- 05
Get AS 4678 engineering design where required
AS 4678 (the Australian earth-retaining structures standard) design applies to any wall over the exemption threshold, or carrying a surcharge load (a load such as a driveway sitting above the wall).
- 06
Confirm the Certificate of Design Compliance (BA3) pathway
BA3 (Certificate of Design Compliance) is WA's actual certification step for an engineered wall - not a Queensland-style form.
- 07
Get a soil/site assessment for your specific block
Depth to limestone, sand type or hills grade varies block to block - don't assume from a neighbour's experience.
- 08
Decide on material based on your site, not just budget
Limestone block, post and panel (galvanised posts with concrete panels), timber and stone all suit different site conditions - the cheapest option isn't always the right one.
- 09
Confirm drainage is included in every quote
Ag-drain (perforated drainage pipe), gravel and geofabric (filter fabric) behind the wall is a structural requirement, not an optional extra.
- 10
Ask how excavation and difficult access are priced
Rock depth and site access are the two biggest real-world cost variables on a Perth retaining wall.
- 11
Get a written, fixed-price quote before work starts
A written scope protects you if site conditions change once excavation begins.
- 12
Check if surcharge loads (driveway, shed, pool) are accounted for
A surcharge load - anything sitting above the wall - changes the engineering requirement, regardless of wall height.
- 13
Confirm stormwater connection for the wall's drainage
Drainage must connect to an approved outlet, not simply daylight onto a neighbouring property.
- 14
Ask about the wall's expected lifespan for your chosen material
Materials vary significantly in service life - factor this into a repair-vs-replace or build decision.