Do I need Council approval for a retaining wall?
- If the retaining wall is going to be built on the boundary line of the site then yes, Council approval is required before you can begin to build.
- If the retaining wall is going to be higher than 600mm from the ground then yes, council approval is required before you can build.
- If in doubt that your retaining wall may or may not be deemed 'exempt development' you should contact your local council service centre or engage an architect.
How do I obtain Council approval?
Retaining wall approval requires; A Statement of Environmental Effects (Minor for retaining walls), a Waste Management Plan, Architectural plans and Engineering details. The architectural plans must be drawn to a recognised scale of 1:100, 1:200 and include a site plan, elevations, section details and a drainage diagram.
The owner may complete the DA application form and lodge the application online via the planning portal NSW.
How much will it cost?
The survey is the first step. A typical survey for a standard 650sqm suburban block is typically around $1,500 - $2,000. In the interest of time and cost, you may be able to survey only the relevant areas of the site. The survey requirements should be advised by the architect prior to undertaking any survey works.
The survey drawing in CAD form would be imported into the architect's software and used for accurate planning and design. The architect would typically charge an hourly rate of $60 - $100 per hour to prepare the site plans, elevations, 3D perspectives and section drawings. A typical retaining wall for a domestic project scope should only take around 1 or 2 days for the architect to draw.
The council or the architect can advise if engineering drawings are needed for your retaining wall design. Retention works which are not deemed to be exempt development will require engineering drawings. The client should engage a licenced structural engineer to prepare detailed engineering drawings specific to the site and project requirements. The engineer can use the CAD drawings from the architect to overlay and draw their details in coordination with the architect's design. The structural engineer should be engaged by the client directly and a suitable fee agreed upon.
Submission to the council of a retaining wall Development Application, Construction Certificate or Complying Development Certificate is to be accompanied by the appropriate development application fee. The application fee is payable to the Council. A Schedule of Fees and Charges can be obtained by contacting your local Council’s Customer Service Centre.
Once the drawings are approved it is time to locate a suitable builder to quote the works. The builder will require the drawings and plans in order to give a quote. It may be worth gathering quotes from separate builders for the works. If the architect is administering the construction contract they may oversee the works, checking for adherence to time, cost and quality in alignment with the original design intent.
What are the risks involved?
Retaining walls constructed on properties without approval (where approval was required), may result in Council pursuing regulatory action such as issuing Penalty Infringement Notices and/or serving Notices and Orders to have the walls demolished.
Retaining walls without adequate drainage design may result in the collapse of the underlying retaining structure or back-flow and flooding of other drainage pits, resulting in erosion of major footings of other primary structures such as house footings.
