How To Build a Sleeper Retaining Wall with Steel Posts

If you’re looking for a project to tackle before summer hits, then building a retaining wall is a fantastic DIY project that anyone can do to transform a backyard from good to great instantly. Sleeper retaining walls support the soil bed, adding to the function and appeal of your garden. If you’re unsure where to start, then you’ve come to the right place. Discover step by step how to build a retaining wall.

What is a Sleeper Retaining Wall?

a fully installed sleeper retaining wall with a steel post

A retaining wall is any wall built to bind earth and soil differently than the elevation beneath it. Sleeper retaining walls go a step further by using additional materials to form the structure, with its name derived from the wooden or concrete planks, usually built for railroad tracks. Timber is a good material for smaller walls. However, for more heavy-duty projects, you’re going to need something a lot stronger. 

Smart Retain™ Wall Posts

Steel Builders is leading the way with the class-leading heavy-duty design of our Smart Retain™  Wall Post system. Offering easy installation for landscaping and civil work, with next day delivery to Sydney, Wollongong and Newcastle, we use a Hot Dip Galvanised finish for protection against corrosion, along with pre-drilled holes to accommodate fence brackets. The Smart Retain™ product is available off the shelf in standard lengths to suit your project and is designed to suit various sleeper products. 

Step 1: Establish Retaining Wall Requirements

While it is recommended that you check with your local council before embarking on your sleeper retaining wall project, retaining walls that are generally under 1m in height do not require approval or an engineering certificate before commencement. However, if the retaining wall is to be built along property boundaries, neighbours would typically share the cost. Check with your local authority to determine which neighbour pays for a retaining wall for more unique situations.

Step 2: Measure Twice, Cut Once

It’s a golden rule for any project, measure twice and cut once, especially for a retaining wall. Before you dig, you’ll need to calculate the amount of Smart Retain™ Steel you’ll require. This calculation will also include the depth of the footing trench where the steel posts will be placed.

Step 3: Digging

Dig a footing depth of roughly the same height as the retaining wall. For post holes, dig holes with a 450mm diameter at the same depth with a 100mm minimum concrete cover below the post. 

Step 4: Secure & Build

After holes are ready, place posts and plumb up along the length of the retaining wall. Pour concrete into holes and level before bracing up to mould in place until concrete sets. Install first sleeper (max 83mm) and check for alignment. After that, you can add the remaining sleepers. Drainage and plastic membrane should now be added as required and backfilled to finish.

The Benefits of Steel

Steel is a manufactured material with isotropic properties, meaning it has the same level of strength everywhere. Because of this, steel has the highest strength-to-weight ratio of any current building material, preventing structural additions from twisting, warping, shrinking or buckling. An often overlooked benefit of steel is its environmental friendliness. The majority of structural steel is made using 100% recyclable steel. 

Steel Builders, for example, source their materials to meet Australian Standards. Steel is also termite-proof and incredibly resistant to fire and heat. Steel also makes for an excellent insulator, as heat can quickly radiate from steel roofing for a cooler home in hotter climates. Furthermore, steel doesn’t require treatment against pests and hazards, reducing the need for toxic chemicals.

Steel Builders are committed to servicing their customer's requirements, supplying quality products, and, most of all, creating smarter solutions. If you need structural steel for your next landscaping project, visit Steel Builders for lintels and t-bars, building and hardware supplies, grates and drains, fasteners and other structural steel products and accessories.

Get a quote today from the premier steel fabricator and building supplier in the NSW domestic housing market for a complete package from CAD drafted shop drawings to painting, galvanising and site installation if required.


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