The 150 Series is our heavy duty steel post range, engineered for concrete sleeper retaining walls between 1.0m and 1.8m in height, reactive clay soils, elevated surcharge loads, and sites where additional structural capacity is required. The larger section size provides significantly greater bending strength and stiffness compared to the 100 Series.
For the most demanding structural applications, see our 200 Series Engineered Posts. For standard residential walls under 1.0m, see our 100 Series Posts.
Post selector
Set your wall details and site conditions. The selector recommends a post series, profile, embedment depth and footing size — and gives you a post count to take to a quote.
Recommended post series
150 Series
H-beam (UC)
Standard soil, garden loading, wall under 1.0 m.
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All figures calculated above are sent with your request, no need to re-enter your measurements.
Post series and embedment are indicative starting points based on published guidelines. Post profile, footing diameter, reinforcement and concrete specification must be confirmed by a qualified structural engineer for walls over 1 m, walls near boundaries, or walls carrying surcharge loads. AS 4678:2002 applies.
Quick reference
Post profile and series depend on wall height, soil conditions and surcharge load. This is a starting reference, not an engineering specification.
| Wall height | Standard soil | Reactive clay / vehicle load |
|---|---|---|
| Up to 0.6 m | 100 Series C-channel | 100 Series H-beam |
| 0.6 m – 0.8 m | 100 Series H-beam | 150 Series H-beam |
| 0.8 m – 1.5 m | 150 Series H-beam | 200 Series H-beam, engineer required |
| Over 1.5 m | Engineer-specified, council approval likely required | |
Post embedment is typically one third of the total post length below ground, increasing on reactive clay or where surcharge loads apply. Footing diameter steps up from 300mm to 450mm for 150/200 Series posts or reactive clay sites. Walls over 1 m generally require engineering certification and may require council approval regardless of post size.
Read the full sizing guide →
