Retaining Walls
Due to changes in the Building Legislation the City’s web pages relating to building related applications is currently under construction. Building Permit Application forms and further information can be found at the Department of Commerce – Building Commission website
The City apologises for any inconvenience.
What is a retaining wall?
A retaining wall is a wall or structure designed and constructed to support soil at a slope steeper than can naturally be supported.
Whilst retaining walls are primarily designed to support soil, they may also be placed under stress from other factors such as buildings, footings, vehicle loads and/or wind loads on dividing fencing. Some pre-manufactured retaining walls are only designed to support soil and not other contributing stress factors.
When is a retaining wall required?
Retaining walls may be required during the construction of dwellings, subdivision of land, erection of dividing fences and/or for landscaping purposes. Whilst the City may require retaining walls to be constructed as part of building works, other retaining walls may be necessary depending on contributing factors as mentioned.
Planning consent is required for the following:
- Where a retaining wall exceeds 0.5m in height from natural ground level and does not meet the required side and rear setbacks under the Residential Design Codes (Variation 1).
- Retaining wall in excess of 0.5m in height from the natural ground level and within the front setback.
- Terraces created at the top of retaining walls in excess of 0.5m are classed as major openings and if do not comply with the Residential Planning Codes for cone of vision setbacks to the boundary.
Cost sharing for common boundary retaining walls
Each landowner has an obligation to retain soil where necessary resulting from earthworks on his/her property. Adjoining owners who have both undertaken earthworks are encouraged to attempt to negotiate a proportional based agreement when retaining walls are required along a common boundary for dividing fencing or landscaping works. When an agreement cannot be reached through arbitration and mediation, then legal action maybe instigated by either adjoining owner and can be costly.
Positioning of dividing fences near retaining walls
Under the City’s Private Property Local Law 1998, a dividing fence is to be positioned on the higher ground of a retaining wall which abuts a common boundary.
Privacy and overlooking
A fence of 1.8m can be erected on top of a retaining wall in excess of 0.5m to prevent overlooking adjoining properties and maintain privacy.
Maintenance of retaining walls
When the City is of the opinion that a retaining wall is structurally inadequate, then the owner is required to consult a practising structural engineer to determine what action, if any, is required to restore the structural integrity of the wall. The cost for the structural engineer’s services is the responsibility of the owner.
Building licence
A building licence is required where a proposed retaining wall exceeds 500 mm in height, is added to an existing retaining wall, and/or in the case of tiered retaining walls exceeds 500 mm in total height. The City requires that such retaining walls are designed by a structural engineer therefore applications are to be accompanied by signed structural engineer’s drawings.
Building licence submission requirements for retaining walls:
- Completed Building Licence Application
- site plan – two copies to a scale not less than 1:200 indicating site boundaries, existing and proposed levels and proposed wall location
- two original signed copies of engineer’s structural details
- application fees
Planning consent requirements
- A planning application via a Codes Approval Application. $139 minimum fee or 0.23% estimated development cost and three (3) sets of plans (in addition to a building licence) including the following:
- Plans drawn to a scale of 1:200 or 1:100 comprising:
- site plan showing the existing contours, and the top and bottom levels of the proposed retaining walls and
- elevation drawings
- Materials of the proposed retaining walls
- A letter of justification to substantiate the variations proposed
- Written support or plans signed from the adjoining owner(s) for the variations sought. If it is not possible to obtain the neighbour(s) comments, the City will advertise the proposal for 14 days
Fees
Planning Schedule of Fees
For further information please contact the City on 9400 4961.
