100UC Steel Posts for Concrete Sleeper Retaining Walls
The 100UC galvanised steel post is the standard choice for most residential concrete sleeper retaining walls in Victoria. Here is what you need to know.
The 100UC galvanised steel post is the workhorse of the concrete sleeper retaining wall industry. It is the most commonly specified post section for residential retaining walls across Victoria — and for good reason.
FPM Building Supplies stocks 100UC steel posts in a range of lengths and configurations for projects across metropolitan Melbourne and regional Victoria.
What Is a 100UC Steel Post?
A 100UC (100 Universal Column) is a structural steel section used as the vertical support post in a concrete sleeper retaining wall system. The sleepers slot horizontally between the posts, which transfer the lateral soil loads down into concrete footings in the ground.
Our 100UC posts are hot-dip galvanised, providing a protective zinc coating that resists corrosion in outdoor and in-ground conditions.
Post Configurations
100UC posts are available in several configurations to suit different positions in the wall:
H Posts — Used as intermediate posts along a straight run of wall, where sleepers continue on both sides of the post.
C Posts — Used at the ends of a retaining wall, where sleepers terminate on one side only.
Corner Posts — Used where the wall changes direction at 90 degrees or 45 degrees.
The configuration required at each position should be confirmed against your wall design.
Choosing the Right Post Length
Post length is not simply the finished height of the wall. A significant portion of each post must be embedded into a concrete footing below ground. The required embedment depth depends on:
- Wall height
- Soil conditions and bearing capacity
- Post spacing
- Surcharge loads (vehicles, structures, slopes)
- Engineering requirements
As a general rule, the below-ground embedment is often equal to or greater than the above-ground wall height — but this must be confirmed by your structural engineer.
Always check your engineering drawings before ordering posts.
When Is a 100UC Post Sufficient?
100UC posts are generally appropriate for:
- Residential retaining walls up to approximately 1.2–1.5 metres in height (subject to engineering)
- Standard residential soil conditions
- Typical post spacings of 1.8–2.4 metres
For taller walls, poor soil conditions or walls subject to heavy surcharge loads, a larger section such as a 150UC or 150UB post may be required.
Galvanising for Long-Term Protection
Retaining wall posts are permanently exposed to soil and moisture. Hot-dip galvanising applies a thick zinc coating that significantly slows corrosion, making galvanised steel the practical choice for long service life in retaining wall applications.
What Else Do I Need?
A complete concrete sleeper retaining wall requires:
- Concrete sleepers — plain, charcoal, or decorative finishes
- Concrete for footings — to set the posts in the ground
- Drainage products — geofabric cloth and ag pipe behind the wall
- Accessories — plastic wedges to space sleepers during installation
FPM Building Supplies stocks all of these products, so you can organise the major components of your retaining wall from one supplier.
Buy 100UC Steel Posts from FPM
FPM Building Supplies is located at 32 Fullarton Drive, Epping VIC 3076. We offer delivery across Victoria.
Contact us on 0421 370 700 or visit us in Epping to discuss your project.
FPM Building Supplies — Concrete Sleepers · Galvanised Steel Posts · Retaining Wall Materials · Victoria-Wide Delivery
Important: Post size, spacing, footing dimensions and embedment depth should always follow the relevant engineering design for your project.
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