Retaining Walls Direct stocks a complete range of galvanised steel retaining wall posts — including H-beam, C-channel, corner, and joiner posts — available in 100 Series (standard), 150 Series (heavy duty), and 200 Series (premium strength). All posts are hot-dip galvanised for long-term corrosion resistance in Australian conditions, from coastal environments to reactive clay soils.
Our steel posts are engineered to work with our full range of concrete sleepers, giving you a fully compatible wall system. Use our Steel Post Sizing Guide to match the right series to your wall height, soil type, and sleeper weight. H-beam posts suit most standard residential and commercial applications; C-channel posts are ideal for lighter walls and fencing; corner and joiner posts are available for 90° and 45° returns.
Trade and bulk pricing available for builders, landscapers, and contractors — open a trade account or request a quote. Delivered Australia-wide.
Post selection for walls over 1m, on reactive soils, near boundaries, or adjacent to structures should be confirmed with a qualified structural engineer.
H-beam posts (also called UC or Universal Column posts) are the strongest option and suit most residential and commercial retaining walls. They have a symmetrical flange profile that provides maximum resistance to lateral soil pressure. C-channel posts (also called PFC or Parallel Flange Channel posts) are lighter and suited to lower walls, fencing applications, or as end posts. Use our Steel Post Sizing Guide to choose between H-beam and C-channel for your project.
Post size depends on wall height, soil type, post spacing, and any surcharge loads (driveways, structures, or slopes above the wall). As a general guide: 100 Series posts suit walls up to 800mm; 150 Series suits walls up to 1.2–1.5m; 200 Series suits walls up to 2m or in difficult soil conditions. Always confirm post sizing with an engineer for walls over 1m, on reactive soils, or near boundaries or structures.
A common guide is to set posts at one-third of the total post length in the ground — so a 1.8m post would have approximately 600mm below grade. Actual embedment depth depends on wall height, soil conditions, and engineer recommendations. In reactive clay soils or where surcharge loads apply, deeper embedment and larger concrete footings may be required. Check with a qualified structural engineer for walls over 1m.
All Retaining Walls Direct steel posts are hot-dip galvanised to AS/NZS 4680 standards, providing excellent corrosion protection in most Australian environments including coastal areas. In extreme coastal conditions (within 100–200m of breaking surf), additional protective coatings may be recommended. Contact us for advice specific to your site.
100 Series posts accept 200mm x 75mm concrete sleepers. 150 Series posts accept both 200mm x 75mm and 200mm x 100mm sleepers. 200 Series posts accept 200mm x 100mm heavy-duty sleepers. All our posts and sleepers are designed as a compatible system — browse our concrete sleepers to match the right size for your post series.
Requirements vary by state and council. Walls under 600mm–1000mm in most states are typically exempt from a building permit, though boundary and land rules still apply. Walls over 1000mm generally require a permit and may require engineer-certified drawings. Walls near boundaries, driveways, pools, or with surcharge loads may require engineering regardless of height. See our Council Approval Guide or check with your local council before starting.
Yes — we deliver steel posts nationwide via crane truck (Hiab) and flatbed freight. Steel posts require specialist heavy freight. We calculate delivery cost based on your postcode, order size, and site access before processing your order. Request a freight quote or call us to discuss delivery to your site.
