Trusted Retaining Wall Posts
for Sydney
Waratah Steel Supplies supplies retaining wall posts to builders, landscapers, and DIYers across the Sydney metro area, from Campbelltown and Liverpool through
to Parramatta, Blacktown, Penrith, and the Hills District. Choosing the right steel post from the start saves cost and headaches down the track. Call 02 9608 9222
to request a free quote and confirm stock availability.
UC Post Grades and Profile Options
Waratah Steel Supplies stocks Universal Column (UC) sections in H-beam and C-channel profiles for standard and heavy-duty retaining wall applications.
Two core grades are available:
▸ The 100UC H-beam suits 75-80 mm sleepers and walls up to approximately 1.8 m under moderate loads.
▸ The 150UC H-beam is the heavy-duty option, recommended for walls above 1.2 m or where clay soils, wet fill, or surcharge loads apply.
Both sections are manufactured to Q235-250 (equivalent to AS1074-250) and hot-dip galvanised to AS1650 for measurable corrosion protection.
What Size Retaining Wall Post Do I Need?
The right post size depends on wall height, soil type, and sleeper thickness. Sydney's geology varies considerably. Sandstone underlies much of the North Shore and Eastern Suburbs, often creating shallow footing conditions. Western Sydney and the Hills District sit on reactive Wianamatta Shale clay, which expands when wet and contracts when dry, placing significant lateral forces on retaining structures.
As a general guide to retaining wall posts:
▸ For walls up to 1.8 m under moderate loads, a 100UC may be suitable.
▸ For walls above 1.2 m, clay-heavy sites, or where surcharge loads from driveways or fences apply, a 150 UC is typically recommended.
▸ On clay sites in Western Sydney, set depths of 1.5 to 2.5 times the exposed wall height are often appropriate.
▸ Always confirm sizing with a structural engineer for walls above 1.0 m, particularly in suburbs such as Blacktown, Liverpool, Penrith, and Camden.
Speak with the team on
02 9608 9222
for guidance on which UC grade suits your wall design.
Galvanised vs Untreated Retaining Wall Posts
Galvanised steel retaining posts offer long-term advantages over untreated steel and treated timber in Sydney's varied soil conditions. Hot-dip galvanising applies
a zinc coating that resists corrosion, rot, warping, and termite damage, particularly in the wetter clay soils of Western and South-Western Sydney. Coastal properties from Cronulla to Palm Beach also benefit, as salt-laden air accelerates corrosion
of unprotected steel. All Waratah posts are hot-dip galvanised to AS1650.
Explore the full range on the
steel products page.
NSW Approval Context for Retaining Walls
Under the NSW Codes SEPP, retaining walls under 600 mm may qualify as exempt development in residential zones. Walls above 600 mm may require a Complying Development Certificate (CDC) or a Development Application (DA) lodged with your local council. Walls above 1.0 m typically require engineering certification. Requirements vary between councils, so confirm the approval pathway before starting work.
Retaining Wall Post Delivery Across Sydney
Waratah Steel Supplies operates from a purpose-built warehouse in South-West Sydney and delivers across the greater metro area. Standard ex-stock items are typically despatched the next business day. Crane truck availability on Tuesdays and Thursdays can assist with on-site unloading. Delivery is also available to Newcastle, Wollongong, and Goulburn.
Suburbs regularly served include Liverpool, Campbelltown, Fairfield, Bankstown, Parramatta, Blacktown, Penrith, Castle Hill, and Baulkham Hills. Find reviews and location details at Waratah Steel Supplies on Google.
How to Order Retaining Wall Posts
1. Call 02 9608 9222 or visit the contact page to discuss your wall height, soil conditions, and sleeper thickness.
2. Receive a free quote covering product grade, cut-to-size options, and delivery cost.
3. Confirm your order, delivery date, and whether crane truck assistance is required.
4. Posts are despatched from the South-West Sydney warehouse, typically the next business day.
Frequently Asked Questions About Retaining Wall Posts for Sydney
What Is the Difference Between 100UC and 150UC Posts?
The 100UC suits walls up to 1.8 m with moderate loads. The 150UC suits taller walls, clay soil sites, or surcharge loads like driveways.
Do I Need Council Approval for a Retaining Wall in Sydney?
Walls under 600 mm may be exempt under Codes SEPP. Walls between 600 mm and 1.0 m may need CDC; walls above require council certification.
Are Galvanised Posts Worth the Extra Investment?
Yes. Reactive clay, coastal salt air, and variable rainfall stress buried steel. Hot-dip galvanising to AS1650 resists corrosion and moisture damage long term.
How Deep Should Retaining Wall Posts Be Set?
Posts are set one-third to one-half of the exposed wall height. Clay sites need deeper depths. Consult a structural engineer for walls above 1.0 m.
Can Waratah Deliver to My Suburb?
Yes. Waratah Steel Supplies delivers across Sydney. Call 02 9608 9222 or visit the contact page to confirm availability and lead times.
Request Your Free Quote Today
Whether your project calls for a 100UC for a standard garden wall or a 150UC for a clay site, the team can help you source the right retaining wall posts in Sydney
at competitive pricing. Call 02 9608 9222 or visit the contact page. The team is available Monday to Friday, 7:30am to 5:00pm.
