Retaining Walls in Kewarra Beach

Kewarra Beach is coastal, mostly gently graded, and the retaining work here is a different problem to the hill suburbs. The walls are generally lower, but the ground and the air both behave in ways that catch out anybody applying a standard detail.

Sand does not behave like soil

The profiles here are sandy, and sand has almost no cohesion. A clay bank will stand at a steep face on its own for a considerable time; a sand face will not stand at all once it is disturbed and wet.

That has two consequences for building a wall. The first is that the excavation itself needs managing. A trench or a cut face in sand can collapse without warning, which is a safety matter before it is a construction one, and it means battering back, benching or shoring rather than simply digging a vertical face.

The second is that the load on the wall is calculated differently. Sand transmits pressure to a wall in its own way, and a wall detailed for cohesive ground is not automatically adequate here. It cuts both ways: sand drains freely, which is an advantage, and it offers little of the self-support that lets a clay bank hold itself.

Footings need attention too. Bearing capacity in loose sand is lower than people expect, and a footing sized by habit can settle. Where the water table sits high, as it does in places close to the coast here, that is a further consideration.

What salt does to a wall

Everything metallic within reach of coastal air corrodes faster, and retaining walls contain a lot of metal that nobody ever looks at again.

Galvanised H posts in a concrete sleeper wall are the obvious case. Standard galvanising has a service life that depends heavily on the environment, and the environment here is more aggressive than a few kilometres inland. It is worth specifying a heavier coating, or a system suited to a coastal exposure, rather than accepting the standard product and finding out in fifteen years.

The same applies to any fixings, brackets, balustrade fittings or fence posts attached to a wall, and to reinforcement in a block wall where cover is inadequate. Concrete cover over steel is what protects it, and skimped cover in a coastal setting brings on spalling far sooner.

Where the exposure is genuinely severe, a core filled block wall with proper cover, or a wall with no exposed steel at all, avoids the problem rather than managing it.

The work that comes up here

Mostly low garden and terrace walls, pool surrounds, planter walls and levelling for outdoor areas. Pool work is common, and walls near a pool bring their own load and fencing questions regardless of how modest the retained height is.

Ring 0468 066 055 or send the form with what you are trying to level out.