This guide has been designed to help explain and step you through the different retaining wall typologies, locations and their interaction with fencing, and to assist you in managing and maintaining your wall and fence.
Developer-built retaining walls maximise the area of level land in your lot. The type, height and location of walls will vary depending on your lot, and should be taken into account when designing your home and landscaping.
Each lot in Brookhaven is individually designed, resulting in every retaining wall being unique. This approach maximises the flexibility of each lot to be customized by each owner now and into the future.
Important retaining wall information that is specific to each individual lot is included in our Disclosure Plans. Retaining wall requirements and responsibility for costs should be discussed with your builder, landscaper, or contractor.
Retaining Wall Types
• At Brookhaven, retaining walls between lots are concrete sleeper retaining walls with galvanised steel “I-beam” posts because of their durability and space saving design. These walls provide more usable level land within your lot.
• Where retaining walls front or adjoin roads and parks (i.e. corner lots), sandstone boulder retaining walls are installed to better complement Brookhaven’s natural aesthetic. These walls are wider and less suitable for side and rear boundaries between lots.
• Logan City Council does not permit timber sleeper retaining walls as part of subdivision works; however these walls are able to be built by residents after settlement, subject to Council approval.
• Timber sleeper retaining walls are economical and appropriate for walls less than 1m high, but require more maintenance and replacement over time. Timber retaining walls are not permitted to street frontages.
• In some cases, lots also have sandstone boulder walls installed in the front few metres of the side boundary to provide a more premium outcome to the streetscape.
Sandstone boulder retaining wall
Concrete sleeper retaining wall
Wall Arrangements
The following diagrams depict the typical retaining wall arrangements used at Brookhaven, in accordance with Council standards and approvals. These walls and their locations should be considered during your house design, construction and operation.
RETAINING WALL HEIGHT (UP TO 2M)
When wall heights are up to 2m in height, a single-lift retaining wall is specified. Retaining walls are generally not installed when the level change between lots is less than 1m.
RETAINING WALL HEIGHT (2M - 3M)
Where wall heights exceed 2m (but do not exceed 3m) in height, a double-tier wall with a landscaping terrace is included. Generally, walls supporting the terrace will be 1m in height, and walls above the terrace will be 2m in height.
RETAINING WALL HEIGHT (OVER 3M)
Where wall heights must exceed 3m, an earth batter is included at the base of, or within the overall retaining wall design. Removal or alteration of earth batters near retaining walls will likely require further design by a structural engineer.
It is important that batters are not altered without structural advice. Batters can be landscaped to screen your retaining wall.
From time to time, some walls may vary from the standard wall typologies. Please refer to the available design drawings for your lot.
1.8m high fence installed by owner, attached to fence bracket
Fence bracket installed by Frasers
Retaining wall (1m high)
Retaining wall (1-2m)
1.8m high fence installed by owner, attached to fence bracket
Fence
by Frasers
1.8m high fence installed by owner, attached to fence bracket
• Developer-built retaining walls are provided to accommodate the earthworks levels that are formed during construction of the lot, as required by the Development Approval issued by Council.
• Developer-built retaining walls cannot be built higher than the approved earthworks levels.
• It is the responsibility of the builder to integrate building and landscape levels with the Developer-built retaining walls and fencing heights.
• Where Developer-built retaining walls do not adequately accommodate selected building or landscape outcomes, additional land owner retaining can be installed.
• Any land owner retaining should be subject to discussion with a builder, landscaper and structural engineer, with regard to load changes to developer-built retaining walls.
• Further certification or Council approvals may be required.
LOADING OF RETAINING WALLS
• Developer-built retaining walls are generally engineered to accommodate a limited surcharge load of up to 5kpa.
• Dwellings located in close proximity to Developer-built retaining walls must be designed and built to not exceed the surcharge load allowance for the retaining wall (i.e. piering of foundations). This will also ensure the dwelling is in some way protected in the unlikely event that the wall is removed.
• Any landscaping (incl. additional retaining) should be designed and built to not exceed the surcharge load allowance for a Developer-built retaining wall.
• Any changes to loading of Developer-built retaining walls should be referred to a registered professional engineer for independent assessment.
• Extra care should be taken not to drive machinery any closer to the wall than the height of the wall (i.e. do not drive within 1.5m of a 1.5m high wall).
DRAINAGE AND RETAINING WALLS
• Developer-built retaining walls are designed and built with drainage zones behind the walls.
• Drainage zones allow groundwater to pass along and through the retaining wall so the wall is not also supporting the weight of this water. Water coming through walls is normal to relieve pressure and is a necessary part of the wall functioning properly.
• The downstream land owner is responsible for accepting and conveying the water that will pass over and through the retaining wall in times of heavy or prolonged rainfall. (i.e. suitable landscaping and/or drainage installations).
• When undertaking landscaping, it is important to consider the drainage that may be present within the rear of walls. Plants should be selected that have a non-invasive root system where possible.
1.8m high fence installed by owner, attached to fence bracket
Retaining wall (height varies)
The wall allows water to pass through to relieve pressure
Builder to connect drainage pit (if supplied) or pipe to stormwater system
draining backfill
Boundaries and Fences
WHERE ARE RETAINING WALLS AND BATTERS LOCATED IN RELATION TO BOUNDARIES?
• Generally, retaining walls are located within low-side lots, to facilitate maintenance and access to the wall face. In some instances, some components (such as drainage) may be located in the higher lot.
• Where lots adjoin public land such as roads and parks, walls generally must be located wholly within the private lot and not encroach into public land. This includes an allowance for footings.
WHERE RETAINING WALLS ARE NOT BUILT
• From time to time, where it is more affordable for a purchaser to install a timber retaining wall after settlement, an earth batter (in lieu of retaining) will be specified by the Developer.
• Earth batters are generally built by the Developer where the height difference between lots is less than 1m. In these locations, a non-engineered, landscape retaining wall can generally be built more economically (by a purchaser) than a concrete sleeper wall.
• Developer-built retaining walls are generally not specified where the height difference between lots is less than 1m in height, as walls less than 1m in height do not require the same engineering.
• Occasionally, earth batters may also be specified in addition to retaining walls, to maximize level lot areas.
FENCING
For Developer-built concrete sleeper retaining walls, brackets are provided to attach fencing directly to the wall if adjoining owners agree. This means fences will sit slightly off the boundary, however this is generally desirable to ensure:
• Ease of maintenance, by limiting the area in the difficult to access location at the top of the wall;
• The least impactful installation, as fence posts do not need to be embedded with footings in the ground; and
• Fence posts will not interfere with the drainage zone behind the wall.
Where adjoining owners do not agree to use the provided fencing brackets, fence alignments default to the property boundary.
For Developer-built sandstone boulder retaining walls, sleeves are provided as close as practicable behind the top of the wall. Sleeves must be used for fence posts.
Where brackets or sleeves are not provided, the fence should be installed in a manner which does not attach to or impact the Developer-built retaining wall.
Design Guideline Requirements
Retaining walls and fences installed to front yards must comply with the Design Guidelines applicable to your lot.
Front yard retaining walls
Must be constructed from materials that complement your approved home and landscaping design. Concrete “I-Beam”, timber sleeper, unfinished block or brick retaining walls are not permitted.
Front fencing
Is fencing forward of the building line, and has different requirements to fences behind your home. Front fencing must be an open-style pool fence with timber posts, at 1.2m in height. Decorative fences will be considered on merit.
Timber fences are not permitted forward of the building line.
Feature corner fencing
Must be completed in accordance with the Design Guidelines applicable to your lot.
Further Information
Details for Developer-built retaining walls, Design Guidelines and fencing can be downloaded from the Brookhaven Build Hub. This can be accessed at:
frasersproperty.com.au/Building-at-Brookhaven
If you would like further advice regarding retaining walls or fencing for your lot, please contact the Customer Care team by emailing customercareqld@frasersproperty.com.au
