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The galvanised steel H-beam middle post (100UC) is the workhorse post for straight retaining-wall runs — its H-shape accepts sleepers on both sides. Hot-dip galvanised to AS/NZS 4680, in lengths from 400 to 3200mm, for 75mm & 80mm concrete and timber sleepers. Australian-made, delivered Australia-wide by Retaining Walls Direct.
Written and product-checked by the Retaining Walls Direct team — supplying steel-post retaining wall systems across Australia. Last updated: June 2026.
H-beam (Universal Column) posts are concreted into the ground at set centres; sleepers drop into the channel on each side, making this the standard middle post along a wall. Pair with our concrete sleepers and finish ends with C-channel and corner posts from the steel post range.
Post length = the retained height above ground plus embedment in the footing. As a rough guide allow embedment roughly equal to the retained height (a 1.0m wall ≈ 2.0m post), but always confirm post size, spacing, footing diameter/depth and embedment with an engineer for your wall height and soil. Posts sit at sleeper-length centres (1.6 / 2.0 / 2.4m). See the steel post sizing guide.
| Section | 100UC (Universal Column), H-beam |
|---|---|
| Role | Middle post — accepts sleepers both sides |
| Lengths | 400 – 3200mm |
| Fits | 75mm & 80mm concrete and timber sleepers |
| Steel thickness | 5mm |
| Galvanising | Hot-dip galvanised to AS/NZS 4680 — no rust, no painting |
| Compliance | AS 4678-2002 Earth-retaining structures |
| Brand | Retaining Walls Direct (Australian-made) |
Fence-bracket and base-plate welding available on request.
Add post caps, fence brackets & hardware and drainage — a drainage kit, ag pipe and geo matting. New to it? See how to build a concrete sleeper retaining wall.
For walls over 1.0m, reactive clay, surcharge loads or fences above the wall, consult a structural engineer (engineered walls over 1 metre), and always plan drainage.
Send your postcode and quantities for a freight quote, or contact the team.
What's a middle (H) post?
An H-beam post that accepts sleepers on both sides — used along straight runs between the ends.
What length post do I need?
Retained height plus embedment — roughly double the wall height as a starting point; confirm by engineering. See the sizing guide.
What sleepers does it fit?
75mm and 80mm concrete and timber sleepers.
Will it rust?
No — hot-dip galvanised to AS/NZS 4680, no painting required.
Can you deliver to me?
We deliver across most of Australia. Send your postcode and quantities for a freight estimate.
