How to construct a load-bearing retaining wall?

[dcameron]

Hi community,
I am building a double-bay 7m x 9m shed on a sloped block and need to construct a 900mm retaining wall to level the ground before putting down the slab. The retaining wall will be aprox 500mm away from the edge of the slab and (once constructed) one side of the shed. My question - are the Ridgi brand 150 x 50mm x 1.5m concrete sleepers & supports rated for this sort of load, or should I be looking at something more substantial for the retaining wall?

[MitchellMc]

Welcome to the Bunnings Workshop community @dcameron. It's fantastic to have you join us, and many thanks for your question about retaining walls.

When it comes to a load-bearing retaining wall that’s going to support a shed slab so close to it, this is definitely something you’ll want an engineer to design and sign off on. The question isn’t just whether RIDGI sleepers are strong enough. The product itself is tested and certified. RIDGI concrete sleepers exceed the requirements of AS4678 Earth-Retaining Structures and AS/NZS4680 Hot Dip Galvanizing, and Australmasonry can provide a certificate from a registered professional engineer confirming compliance with the National Construction Code.

What really matters here is how the wall is designed and constructed for your specific site conditions. A 900mm retaining wall sitting only 500mm away from a slab will be carrying not just soil load, but potentially surcharge loads from the shed and slab as well. That changes the engineering requirements considerably.

RIDGI sleepers and posts are a compliant product, but you'll need an engineer to assess the design of the wall and ensure the footings, post spacing, and wall thickness are all suitable for the load in your situation. That way, you’ll know the wall is both safe and NCC-compliant.

Please let me know if you have any questions.

Mitchell