Retaining Walls in Gordon

A Tuggeranong suburb named for a poet

Wikipedia says Gordon is a suburb in the Canberra district of Tuggeranong, with the postcode 2906, and that it is named after the poet Adam Lindsay Gordon, who lived from 1833 to 1870. It was gazetted on 12 March 1987. The streets are named after sportspeople, and the article gives Woodfull Loop as an example, named for the captain of the Australia cricket team in the Bodyline series. If you are reading about a wall here, you are probably in a younger suburb with houses from the late twentieth century onwards.

Where it sits

The article places Gordon next to Bonython, Conder and Banks, on the west side of Tharwa Drive. It names Point Hut Pond and the Point Hut district park as features within the suburb, and says Gordon has a primary school and a neighbourhood oval. A block close to a pond or a park edge may have a fall towards open ground, and ACT Planning has a separate building approval check for walls on any block, so read it for yours.

The ground under Gordon

Wikipedia's geology section says Quaternary alluvium is found in the south and centre of Gordon, and that Deakin Volcanics rhyodacitic crystal tuff from the Silurian age lies at the surface in the north. Alluvium is sediment laid down by water, and rock is a different digging job from soft ground. We cannot say what lies under a particular block. Ask each builder how they will find out, whether by a test hole or a look at the cuttings nearby, before they fix a footing price.

What Yakka Labour says about digging and drainage

Yakka Labour says the groundwork often decides the price, with machine excavation and disposal at $60 to $150 per cubic metre and drainage at $40 to $100 per linear metre. It adds that rock can turn a two-day dig into a week. In a suburb where the geology changes from alluvium to volcanic rock within a few streets, two neighbours can get very different quotes for the same wall, so ask for the groundwork to be listed line by line.

Approval before you build

ACT Planning says a retaining wall does not need a building approval if it is not higher than 1.2 metres from the top of the wall to the lowest adjacent ground level. Its development approval page gives lower limits, 0.4 metres, for parts of a wall within 1.5 metres of a side or rear boundary. Both pages apply in Gordon as anywhere in the ACT. Access Canberra keeps the register of builders with the right licence where you can check a business's licence.

Where to start

If the wall is a long, low sleeper wall, read our concrete sleeper guide. If it is tall, near a boundary or holding up a driveway, read the engineered walls guide first.

Is Gordon near a creek or pond that affects retaining walls?

Wikipedia says Point Hut Pond and the Point Hut district park lie within the suburb. We cannot say how that affects any block, so ask each builder how they will handle water behind your wall.

Does a Gordon retaining wall need approval?

ACT Planning says a wall not higher than 1.2 metres does not need a building approval, and its development approval page sets separate limits near boundaries. Check both pages or ask a certifier.

What is the geology in Gordon?

Wikipedia says Quaternary alluvium lies in the south and centre and Silurian Deakin Volcanics tuff lies in the north. It is general information, not a site assessment.