Concrete Sleeper Retaining Walls Mandurah

How a concrete sleeper wall works

A concrete sleeper wall is an "embedded post" wall. Galvanised steel posts, usually H or C shaped in section, are set into holes in the ground and concreted in. Precast concrete sleepers slide down between the flanges of the posts, one on top of the next, until the wall reaches the right height.

The posts do most of the structural work. They act like cantilevers, held firmly at the base by their concrete footings and resisting the push of the soil behind the sleepers. That is why post size, spacing and footing depth matter more than anything else on this type of wall.

Because the sleepers are thin compared with limestone blocks, a sleeper wall takes up very little of the yard. On a narrow side setback or along a fence, that space can be worth a lot.

Why they have become so common in the Peel

Newer estates across the City of Mandurah were built on filled and levelled pads. Where one lot sits higher than the next, the boundary needs a wall, and a straight run of sleeper wall with a fence on top is a tidy answer. They are also widely used:

Around pools, where the ground on one side has to be held back and a pool fence goes on top.
Beside driveways that have been cut below natural ground.
Behind sheds and patios where a level pad has been cut into a slope.
Along side setbacks, where there is no room for the thickness of a block wall.

On sandy ground, the posts are easy to drill or dig for, which keeps the build quick. Where limestone rock sits close to the surface, holes may have to be cored or broken out, which takes longer and should be allowed for in the quote.

Choosing sleepers

Sleepers come in a range of lengths, heights and thicknesses, and in several finishes:

Plain smooth grey, the most economical, often used where the face will be covered by planting.
Woodgrain that imitates a timber sleeper without the rot.
Stacked stone or split-face patterns for a more decorative face.
Coloured sleepers, cast with oxide through the concrete or coated on the face.

Thicker, reinforced sleepers are used for taller walls and longer spans. The contractor will match sleeper size to the height and post spacing.

The parts you will not see

Footings. Each post sits in its own concrete footing. Depth depends on wall height, the soil, any load above the wall (a driveway, a shed, a pool) and the product's design tables or an engineer's design.

Post protection. Steel and salt do not mix. On coastal and canal-side lots, ask about the galvanising standard and whether the base of each post is protected from standing water.

Drainage. As with any retaining wall, water must be able to get out. A slotted pipe along the base in a bed of drainage gravel, with an outlet to a soak well, garden bed or the street drainage where permitted, keeps the pressure off the wall.

Fabric. Geotextile fabric behind the sleepers stops sand washing through the joints and out the ends.

Things that go wrong

Most sleeper wall problems we hear about trace back to one of these:

Posts that are too small or spaced too far apart for the wall height.
Footings that are too shallow, so the posts lean forward over time.
No drainage, so the wall is holding back wet, heavy ground every winter.
Extra load added later, such as a shed, a spa or parked cars close to the top of the wall, that the wall was never designed for.
Corroded steel on lots with salt exposure or poor drainage.

If an existing sleeper wall is leaning, cracked at a post or bowing, see repairs and rebuilds.

Permits, engineering and boundaries

Many sleeper systems are sold with engineering tables that set post size and footing depth for given heights and soil types. Where a wall falls outside those tables, or carries extra load, a structural engineer's design may be needed. Councils in WA commonly require a building permit once retained height passes about 500 mm, and boundary walls can also be affected by the Residential Design Codes. The City of Mandurah or the Shire of Murray will confirm what applies to your lot.

Getting a quote

Measure the run and the highest point, note what will sit on top, and call (08) 9515 3332 or use the form below. Planning prices for sleeper walls are on the retaining wall cost guide, and the limestone and block pages explain the alternatives.

Compare other wall types

Limestone Retaining Walls	Reconstituted and natural limestone block walls, the classic Peel-region choice for sandy front and back yards, planter beds and boundary steps.
Timber Retaining Walls	Treated pine or hardwood sleeper walls for low garden terraces and edging, where budget and a softer look matter more than a long life.
Block & Masonry Walls	Core-filled concrete block, segmental interlocking block and rendered masonry walls for taller cuts, driveways and engineered jobs.
Wall Repairs & Rebuilds	Leaning, bulging or sand-leaking walls assessed, re-set or rebuilt, with the drainage problem that caused the failure fixed at the same time.
Site Prep & Earthworks	Levelling, cut and fill, compaction and footing prep with small machines before a wall goes in, so the wall sits on ground that will not move.

Quoted across Mandurah, Halls Head, Meadow Springs, Silver Sands, Pinjarra, Dudley Park, Greenfields, Coodanup, Erskine, Falcon, Wannanup, Dawesville, San Remo, Madora Bay, Lakelands, Parklands, Furnissdale, Ravenswood, North Yunderup, Barragup.

Questions people ask before they commit

How long do concrete sleeper walls last?

A well built concrete sleeper wall with properly galvanised posts and reinforced sleepers can last for decades. The weak points are posts that are too light for the height, footings that are too shallow, and steel that corrodes, which is worth thinking about on lots near salt water. Ask the contractor what post coating and sleeper reinforcement they use.

Are concrete sleepers suitable near the ocean or a canal?

They are used on coastal and canal lots, but salt air and salt water speed up corrosion of steel. Heavier galvanising, keeping steel clear of standing water, and good drainage all help. On a water-facing lot, confirm with the City of Mandurah whether any part of the work affects a canal or foreshore wall before you go ahead.

Can a fence go on top of a sleeper wall?

Yes. Many sleeper walls on boundaries carry a dividing fence or pool fence. The posts are usually extended or a separate fence post is fixed beside them, and the wall design has to allow for the wind load the fence adds. Mention the fence at the quote stage.

Do concrete sleeper walls need a permit?

They are treated like other retaining walls. In WA a building permit is commonly needed once a wall retains more than about 500 mm of ground, and many sleeper products come with engineering tables for set heights. Check with the City of Mandurah or the Shire of Murray for your lot.

Will sand leak through the gaps between sleepers?

It can, at the ends and joints. A sheet of geotextile fabric behind the sleepers, lapped at the posts, stops most of it. Fabric is a small part of the cost, so make sure it is on the quote.

Concrete Sleeper Retaining Walls Around Mandurah