Hot dipped galvanised steel posts are what hold a post and panel wall up. Sleepers do the retaining across the span, the posts carry the load into the ground, so post size, spacing and...
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About Steel Posts
Hot dipped galvanised steel posts are what hold a post and panel wall up. Sleepers do the retaining across the span, the posts carry the load into the ground, so post size, spacing and embedment depth are the numbers that matter most.
We stock C channel and H posts from 0.4m to 3.8m, 45 and 90 degree corner posts with a full steel plate connecting the two channels, and a heavy duty 150 series range for larger engineered walls.
Standard or heavy duty
- Standard 100 series, 100PFC C channel and 100UC14.8 H posts, in 12 lengths from 0.4m to 3.8m, in 0.4m steps to 2.8m then 0.2m steps. These suit the great majority of residential walls.
- Heavy duty 150 series, 150UC23 H posts and 150PFC C channel, in 19 lengths from 2.0m to 6.0m. Priced online and ready to order, so an engineered wall post does not have to wait on a quote.
Section sizes at a glance
| Section | Mass | Depth | Flange width | Clear depth between flanges |
|---|---|---|---|---|
| 100UC14.8 H post | 14.8 kg/m | 97mm | 99mm | 83mm |
| 100PFC C channel | 8.33 kg/m | 100mm | 50mm | 86.6mm |
| 150UC23.4 H post | 23.4 kg/m | 152mm | 152mm | 138mm |
| 150PFC C channel | 17.70 kg/m | 150mm | 75mm | 131mm |
Section properties are the standard AS/NZS 3679.1 hot rolled sizes. The clear depth is the gap the sleeper sits in, which is what decides whether your sleeper thickness fits the post.
As a rule of thumb the post is twice the wall height, because the recommended pier depth equals the height of the wall, which is why a 3m wall needs a 6m post. Use the wall calculator to size and count them, and it will point you at the heavy duty range automatically once the required post passes 3.8m.
Good to know
Walls that need 150 series posts are engineered walls. Engineering in Queensland must be carried out by or under the supervision of a Registered Professional Engineer of Queensland, and taller walls generally need council approval as well. Thresholds and conditions are not the same in every council area, so confirm what applies to your site with your council or a licensed building certifier before you order.
Post spacing and depth depend on your wall design. Our steel post installation guide covers the spacings we use for each sleeper length and embedment by wall height, and the guide to choosing steel posts works through C versus H at each position. Where your wall has an engineered design, use the spacings in that design rather than a rule of thumb.