Updated October 2026
Clontarf is flat, sandy and bayside, with the foreshore parkland along one edge and streets of 1960s to 80s housing behind it. There is no hillside here and there never was. What there is, on almost every block, is sand that moves, a water table closer to the surface than people realise, and a lot of low walls built decades ago by owners who reasonably assumed that a knee-high wall on flat ground could not go far wrong. Mostly those walls are not falling over. They are sinking, spilling and losing the ground behind them.
We connect you with experienced local builders who work Clontarf and build for the sand rather than against it.
Fabric matters more than muscle
On a clay block, a wall fails because trapped water pushes it over. On a Clontarf block, the water leaves easily and takes sand with it. Fine material washes out through the gaps between sleepers or around a shallow footing, the ground behind drops into the void, and the wall ends up holding far less than it was built to hold. You can see it as a dip in the lawn a metre back from the wall, or as sand fanning out across the path after every storm.
The fix is geotextile fabric behind the face, correctly lapped, used to keep the soil in rather than to keep gravel clean, combined with backfill that lets water through and a footing set deep enough that loose sand is not doing the work. Heavier sleepers do not solve this. Detailing does. Our retaining wall drainage page covers it properly.
What tends to go first
Timber at the ground line, because that is where it stays damp. Footings, because sand gives a post less grip than firm ground and posts gradually lean. And the ground behind, which is the one most people notice last. A wall that still looks straight can have a hollow behind it, which is why a builder will often probe rather than just eyeball.
Sensible choices for a Clontarf block
For low garden work and terracing, timber retaining walls remain a fair option when they are detailed for sand. For driveway edges, pool surrounds or anything that will carry load, concrete sleeper walls are the better call because the posts go deeper and the system tolerates a wet base.
Councils and the QBCC set height and engineering thresholds for retaining walls in Queensland, and the builders we work with confirm what your wall needs before quoting.
Frequently asked questions
There is a dip in my lawn behind the wall. What causes that?
Almost certainly sand migrating out through the wall. The surface drops to fill the space left behind. Topping it up works until the next storm, which is the clue.
Do I need drainage if sand already drains well?
Yes, but the purpose shifts. It is less about releasing trapped water and more about controlling where the water goes so it stops carrying your yard with it.
How deep do footings go in sand?
Deeper than on firm ground, and the exact depth depends on wall height and what the builder finds when digging. It is one of the reasons a Clontarf quote should follow a site visit.
Get it looked at before the yard drops any further. Get a fast quote
We also cover nearby Woody Point and Margate.