Balustrading and Fencing for Retaining Walls: What You Need to Know

Retaining walls are used in various settings, from motorways and public parks to residential properties, to hold back soil and create level surfaces. While these structures are essential for stability, they often require additional safety measures such as fencing or balustrading, especially when there is a potential for falling.

Adding a balustrade or fence to a retaining wall is more than just a design choice — it’s often a compliance requirement under Clause F4 of the New Zealand Building Code. The strength of the barrier needed depends on the location and purpose of the retaining wall, as well as the risks associated with potential falls. Let’s explore when and why balustrading is necessary and the key factors to consider when incorporating it into your project.

When Is Balustrading or Fencing Required?

Clause 4 of the Building Code states that any potential fall over 1 metre in height must have a barrier to protect people from falling. For example:

●       A motorway retaining wall might require fencing to protect pedestrians.

●       A residential retaining wall for a backyard could need balustrading for safety.

●       Public spaces like parks or shared pathways often require fences or balustrades to manage risks for pedestrians and cyclists.

The specific requirements for barriers vary based on the area’s use. For instance, a rooftop bar will need different specifications than a residential retaining wall.

Key Consideration: Designing for the Additional Force of Fencing

Adding fencing or balustrading to a retaining wall introduces extra load to the structure. This additional force must be accounted for during the design and construction process to ensure the wall’s structural integrity is not compromised.

At Urban Group, we’ve worked extensively with councils and engineers to provide balustrades and fencing solutions that meet safety standards while maintaining compliance with the building code.

The Compliance Pathway

When adding balustrades to retaining walls, you’ll need to provide the council with a Producer Statement (PS1) to confirm the product meets building code requirements. This includes details on how the balustrade is connected to the retaining wall or structure.

To simplify this process, Urban Group has developed a range of pre-engineered balustrade solutions that meet standard PS1 requirements. For more complex projects, we can work with you to provide customised solutions and site-specific PS1s.

PS1s for balustrading can be downloaded here:

●       1200mm high Premier Balustrade PS1 for Balustrading & Retaining Wall Barriers

●       1000mm high Premier Balustrade PS1 for Balustrading & Retaining Wall Barriers

●       1200mm high Maximus Balustrade PS1

Understanding C3 and C5 Loading Requirements

Balustrade loading requirements depend on the area’s occupancy type, as outlined in Table 3.3 of AS/NZS 1170.1:

●       C1/ C2 is loading for areas with fixed seating, such as for restaurants and bars.

●       C3 refers to the barrier loads for external balconies, stairs, landings, and edges of roofs in domestic and residential buildings. C3 is an occupancy type that describes areas that are not susceptible to overcrowding such as a balcony on a residential property

●       A C5 crowd loading balustrade is a type of balustrade that is designed and tested to meet specific load requirements for crowds or people gathering in public spaces, such as high traffic footpaths.

●       A D rating applies to retail areas including public areas.

Case Study: Riverside Warehouses, Auckland

For the Riverside Warehouses project in Highbrook, Auckland, Urban Group provided fencing and balustrading for shared pedestrian and cyclist pathways. Some areas had drop-offs of up to 4 metres, requiring customised solutions to meet occupancy type C5 under F4 Safety from Falling in the NZ Building Code, which required the fencing to meet higher imposed loads.

Secura and Maximus were chosen to meet both safety and efficiency objectives for the client. They both come as standard panels ex-stock but can be easily adapted which enabled the project team to design a solution that met specific requirements. Project architect Jonathan Walker explains, ‘That’s where Urban Group was great. They gave us a lot of information and support to meet those codes and engineering requirements, which we achieved with the least amount of customisation and cost.’

Balustrade Design and Materials

The purpose of the balustrade or fence often dictates the materials used. Common choices include:

●       Aluminium Fencing such as Urban Groups Premier: Ideal for areas with views or road frontage, often used in parks, cycle lanes, and schools.

●       Steel, Timber or Composite Fencing such as Urban Groups StabiFence or ColourFence: Suitable for areas requiring privacy or additional durability. Popular for settings where aesthetics and privacy are priorities.

For higher-risk areas, standard products may need modifications to meet code compliance, such as:

●       The spacing of posts at closer intervals

●       Using larger posts to withstand increased pressure

●       Or a bespoke solution may be required

Urban Group offers a range of standard and customisable solutions to suit your project’s requirements.

Conclusion

Balustrading and fencing on retaining walls are essential for safety, compliance, functionality and aesthetics. From residential properties to public spaces, understanding the building code requirements and the structural implications of added barriers is critical to choosing the correct solution for each project.

At Urban Group, we provide both pre-engineered and customised solutions to help you meet compliance requirements while achieving the desired aesthetic and functionality. If you’re planning a project involving retaining walls, get in touch with us to discuss how we can support your project.

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Urban Group offers expert advice and a wide range of balustrade and fencing solutions to meet NZ Building Code standards. Let us help you create safe and compliant retaining wall systems balustrading for your next project.

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