Updated October 2026
Regents Park is 1980s and 1990s housing in the 4118 postcode on blocks with enough room that a lot of owners have added to them over the years. Pools, sheds, carports, wider driveways, water tanks, decks and alfresco slabs have all gone in long after the houses did.
That is the retaining wall story here. Many of the walls on these blocks are now carrying something they were never designed to carry, and that is both the common cause of movement and an approval trigger in its own right.
We connect you with experienced, insured local builders who work Regents Park and will ask what sits above the wall before they quote.
Surcharge loading, in plain terms
A retaining wall is designed to hold a wedge of soil, and the engineer works out the push from that soil. Put something heavy above the wall, within the zone of ground that leans on it, and the push goes up. A pool holds tonnes of water. A shed slab, a vehicle, a tank, a deck footing all add load the same way.
That is what surcharge loading means, and it is why a wall that behaved for 20 years can start moving the summer after the pool went in. It is also why a replacement in the same position may need engineering when the original never had any.
If anything has been added above your wall, say so on the form. It changes the assessment, the design and the approval position. Our retaining wall repairs page covers how builders work through it.
What the council publishes
Logan City Council publishes its own criteria, which is more than most councils do. 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.
Read the first and third parts together. A load above the wall takes it out of accepted building work even if the wall is low, and surcharge loading over the zone of influence is listed as a trigger on its own. The proximity trigger is the third one worth knowing, because it catches low walls close to the house, the shed or another wall regardless of height.
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 the position for your own wall with Logan City Council or a private building certifier before you build.
Rebuilding for the load
Where a wall is carrying a real surcharge, block retaining walls are often what the engineer draws, and concrete sleeper walls with deeper piers and heavier posts handle plenty of it too. Drainage still decides the lifespan: ag-pipe to a legal point of discharge, gravel backfill, geotextile fabric and weep holes or outlets. See retaining wall drainage.
Treat any per-metre figure as guide pricing and read our retaining wall cost guide before comparing quotes.
Tell us what is sitting above the wall. Get a fast quote
We also cover nearby Heritage Park and Browns Plains.
Frequently asked questions
The wall moved the year after we put the pool in. Connected?
Very likely. A pool and its water are a significant load, and if it sits within the zone of ground leaning on the wall, the push on the wall went up. Tell the builder it is there, because it changes both the diagnosis and the design.
Does a pool above a wall need the wall approved?
Surcharge loading over the zone of influence for the wall is one of Logan City Council's listed approval triggers, so expect it to. Confirm with the council or a private building certifier, and note that pool work carries its own Queensland safety requirements separately.
Can I put a shed above an existing wall?
Ask before you pour the slab, not after. A shed above a wall is a load the original design may not allow for, and it is cheaper to find out at the planning stage than to rebuild the wall later.