Alkimos is one of the newer coastal growth areas in Perth’s north, part of the City of Wanneroo. Its estates are built over dune country close to the ocean, so new lots often come with significant level changes, developer-built walls, and back yards that need retaining before landscaping can start. Retaining Walls Perth connects Alkimos homeowners with a local, insured specialist for a free quote.
Call 0485 557 649 for a free, no-obligation quote from a local, insured Perth retaining wall specialist.
Typical Alkimos jobs
- Back-yard retaining on new builds, before lawn and paving go in
- Side boundary walls where the developer’s pad levels left a step
- Terracing steep rear yards for usable outdoor space
- Pool and patio retaining
- Front-yard walls matched to estate design guidelines
Estate guidelines and LDPs
New coastal estates in Alkimos typically come with design guidelines and local development plans that can control front-yard wall heights, materials and fencing. The R-Codes also say that within 1 m of a lot boundary, fill should be no more than 0.5 m above natural ground at the boundary unless a local development plan says otherwise, so your LDP may set different limits. Check your estate documents before choosing a design.
Working with developer walls
Many lots already have walls built by the developer at subdivision. Before adding a new wall in front of or on top of one, your specialist and engineer need to know what’s there, because adding height to an existing wall needs a City of Wanneroo building permit, and loading the top of an existing wall changes its design.
Coastal conditions
Close to the ocean, expect salt-laden air, and have the ground on your lot checked rather than assumed. Good compaction, correct post depth, and corrosion protection on steel posts and fence fixings are worth asking about.
Permits in Alkimos: City of Wanneroo
The City of Wanneroo requires a building permit where a wall exceeds 500 mm, is an addition to an existing wall, or tiered walls exceed 500 mm in total. Planning approval is needed in the Residential zone where walls don’t comply with the R-Codes, and must be obtained before the building permit is issued. The R-Codes also limit fill within 1 m of a boundary to 0.5 m above natural ground unless a local development plan says otherwise, so check any estate LDP. Full detail in our WA permit guide.
What it might cost
Published Perth guides put typical installed prices as of 2026 at about $260 to $630 per lineal metre for concrete sleeper walls and about $420 to $680 per square metre of face for limestone, before drainage, engineering and permits. These are typical ranges, not quotes; see the Perth cost guide. Your Alkimos specialist will price your actual site.
Alkimos retaining wall questions
My builder left a big drop at the back. Is that normal?
It’s common on coastal estates. Check your building contract for what retaining was included, then get a quote for the rest.
Do you cover Eglinton and Yanchep?
Call 0485 557 649 to check coverage for your address.
Get a free Alkimos quote
Retaining Walls Perth is a referral service: we connect Alkimos homeowners with a local, insured retaining wall specialist, who quotes and contracts with you directly. Call 0485 557 649, or see other areas we serve.
Sources
- Landscapes WA, "Retaining wall cost in Perth" (12 Sep 2026)
- What's The Damage, "Retaining Wall Cost Perth 2026"
- Luke's Landscaping Co., "Limestone vs concrete retaining walls in Perth" (2026)
- The Quote Yard, "Concrete Sleeper Retaining Walls WA 2026"
- Building Regulations 2012 (WA) Sch 4 cl 2 item 6
- R-Codes Vol 1 cl 5.3.7 & Table 4 (10 Apr 2026)
- Building Act 2011 (WA) s89
- Legal Aid WA, dividing fences and boundary issues
- City of Wanneroo
- Soil context: Australian Geomechanics Society, Residential footings – Perth metropolitan area
- Luke's Landscaping Co. (24 Jul 2026), Perth soils by suburb