Free Quote on Any Order — Call us today for expert advice and a no-obligation quote on your retaining wall project.
Australia's Retaining Wall Specialists
Quality concrete sleepers & steel posts delivered Australia-wide
$49.00
Add your deal, information or promotional text
No products found in this collection
Retaining Walls Direct supplies hot-dip galvanised H-beam steel posts direct to Townsville and North Queensland — delivered by crane truck to your site across Townsville, Thuringowa, Kirwan, Aitkenvale, Mundingburra, Hermit Park, Belgian Gardens, Magnetic Island, Charters Towers, Ingham, and surrounding areas. No depot markups, no middlemen — direct-to-site pricing with freight calculated at checkout.
With over 50 years of hands-on retaining wall construction experience across Australia, we understand Townsville's demanding retaining wall environment. Townsville sits on a distinct geological boundary — granitic and metamorphic hills to the north and west, and deep black cracking clay (Vertosol) plains to the south and east. This creates dramatically different post sizing requirements across the city. Townsville's tropical climate — a pronounced wet season from November to April delivering 1,100mm of rainfall, followed by a long dry season — drives extreme wet-dry soil movement cycles that are among the most damaging to retaining walls in Australia.
100 Series posts are suitable for walls up to 600mm on well-drained granitic or metamorphic hillside sites with no clay subsoil and no surcharge load. In Townsville, this applies to a limited number of sites on the Castle Hill and Bohle River granite terrain. If any clay is present at footing depth, default to 150 Series minimum.
150 Series posts are the correct specification for walls 600mm–1.0m on moderate clay sites and hillside transitions. Suitable for Kirwan, Aitkenvale, and Mundingburra sites where clay is present but the wet-dry cycle is less extreme than the southern black soil plains.
200 Series posts are the correct and only specification for all Townsville black soil plain sites, all walls over 1.0m, and any wall with surcharge loading. Townsville's southern and eastern suburbs — Thuringowa, Kelso, Bohle Plains, Cluden — sit on deep black cracking clay (Vertosol) soils that are Class H2 reactive under AS 2870-2011. These soils crack to 500mm depth during the dry season and expand explosively when the wet season arrives — generating lateral forces that 150 Series posts cannot resist.
On Townsville's black soil plains, posts must penetrate through the full depth of the cracking clay layer and into stable subsoil. Footing holes on black soil sites may fill with water during the wet season — pour concrete immediately.
All our H-beam posts are hot-dip galvanised to Australian standards. Townsville's tropical climate — high humidity year-round, salt air within 5km of the coast, and cyclone wind loading (Wind Region C) — is one of Australia's most aggressive corrosion environments for steel. Hot-dip galvanising is the minimum standard for all Townsville retaining wall posts.
In Queensland, retaining wall approvals are governed by the Building Act 1975 (QLD):
Townsville falls under Townsville City Council. Charters Towers falls under Charters Towers Regional Council. Ingham falls under Hinchinbrook Shire Council. Always confirm cyclone wind region requirements with your council before commencing work.
Townsville's southern and eastern suburbs sit on deep black cracking clay (Vertosol) soils — Class H2 reactive under AS 2870, the highest standard residential classification. During the dry season these soils crack to 500mm depth. When the wet season arrives they absorb water explosively and expand with enormous lateral force. This wet-dry cycle generates lateral forces on retaining wall posts that 150 Series posts cannot resist over multiple seasons. 200 Series posts with deep concrete footings are the only correct specification for Townsville's black soil plain sites.
Yes — Townsville is in Wind Region C under AS 4055, requiring structures to be designed for cyclonic wind loads. For walls over 1.0m, engage a structural engineer to confirm post sizing and footing depth for cyclone wind region requirements. 200 Series posts with deep concrete footings are the correct specification for cyclone-affected sites.
Townsville's black soil plains experience extreme wet-dry soil movement. During the dry season, clay shrinks and cracks — reducing lateral support on post footings. When the wet season arrives, the clay expands rapidly, generating lateral pressure on posts. Posts must be set deep enough to anchor below the active zone of clay movement — minimum 900mm on black soil sites for walls up to 1.0m. Shallow footings on black soil will move seasonally and eventually fail.
Yes — we deliver to Charters Towers, Ingham, and surrounding North Queensland areas. Freight is calculated at checkout to your postcode. For remote North Queensland deliveries, contact our team to confirm crane access and lead times before ordering.