Updated October 2026
Hillcrest is 1980s and 1990s housing in the 4118 postcode, west of the motorway corridor, on ground with modest fall. Alongside the original estate walls there is a lot of owner-built work here: sleeper walls, garden terracing and step walls put in by the people who lived in the houses, over several decades.
Some of that work is excellent. Some of it is a stack of material that has been holding on. The useful thing is knowing which one you have before you spend money on it.
We connect you with experienced, insured local builders who work Hillcrest and will check what is actually behind the face rather than assuming a standard build.
Checking an owner-built wall
A builder assessing a wall they did not build looks at a short list. Are the posts rated for in-ground use, and are they sound at ground level? Is there a footing, and how deep? Is there an ag-pipe behind the base, does it have fall, and does it actually go anywhere? Is there a gravel column and geotextile fabric, or is clay sitting straight against the face? Is anything untreated bridging soil to the house frame, which matters in termite country?
Say up front that the wall was owner-built when you ask for a quote. It changes what the builder opens up, and it is the difference between a useful assessment and a guess. Our retaining wall repairs page covers how the call gets made.
The estate walls
The other half of the work here is the standard end-of-life story. Timber sleeper walls last 15 to 25 years when drained properly, and the original walls on these blocks are past that. The failure is at the posts, at ground level, and the lean is the last symptom.
Concrete sleeper walls are the usual replacement because nothing in them rots or gets eaten. Timber retaining walls remain the cheapest to build for low garden terracing away from the house. Whatever goes in, drainage decides the next 25 years rather than material. See retaining wall drainage.
Approvals, and the owner-built catch
Logan City Council publishes its own criteria. A retaining wall up to 1 metre high from natural ground level is accepted building work provided no loads are imposed above it, such as a building, a structure or a driveway. Approval is required where the total height of the wall and of the fill or cut retained by the wall is greater than 1 metre, where retaining walls are constructed closer than 1.5 metres to any other building or other retaining wall regardless of the height of the walls, or where there is surcharge loading over the zone of influence for the wall.
An owner-built wall from 20 years ago was probably built on the assumption that under a metre meant no paperwork. The proximity trigger says otherwise: a wall closer than 1.5 metres to any other building or retaining wall needs approval regardless of the height of the walls. If you are replacing or extending that wall, the current criteria apply to the new work whatever happened last time.
The rules behind the criteria sit in the Building Regulation 2021, and Logan City Council and private building certifiers apply them. The QBCC licenses the contractor separately, and Queensland requires a QBCC licensed contractor for building work valued over $3,300. The council's criteria document is undated on its face, so confirm your own job with Logan City Council or a private building certifier before you build. Before any digging, your builder should lodge a free Before You Dig Australia (BYDA) enquiry to locate underground services.
Treat any per-metre figure as guide pricing and read our retaining wall cost guide.
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We also cover nearby Browns Plains and Boronia Heights.
Frequently asked questions
I built the wall myself. Will a builder tell me it is all wrong?
A good one will tell you what is sound and what is not, which is often a mix. Plenty of owner-built walls have good timber and no drainage, and that is a fixable problem rather than a rebuild.
Does an owner-built wall need approval retrospectively?
That is a question for the council or a private building certifier rather than this page, and it depends on the wall. What is clear is that new work has to meet the current criteria, including the 1.5 metre proximity trigger.
Is untreated timber in the ground a problem?
Yes, especially in termite country and especially where it bridges soil to a house frame. H4 treated pine is rated for in-ground use. A builder will raise it on the assessment.