5 Design Tweaks that Slash Ballast Costs for Temporary Structures
When designing temporary structures for outdoor events such as truss stages, LED walls, or archways wind loads are one of the most critical factors to address.
Typically, designers rely on concrete ballast blocks to provide the necessary stabilising forces. However, ballast adds cost, time, and complexity to installations.
At Brushwood Engineering, we believe that smarter design can dramatically cut down ballast requirements without compromising safety or compliance.
Here are five proven ways to reduce the ballast you need for your next activation:
1. Maximise the Structure’s Self-Weight
Increasing the self-weight of your structure is one of the most effective ways to naturally counteract uplift forces without external ballast.
As outlined in AS/NZS 1170.2:2021 (Structural Design Actions – Wind Actions), dead loads (such as the weight of structural elements) can be included when calculating resistance to overturning and sliding under wind load.
Strategies include:
- Specifying heavier base plates or steel frames, particularly at key supports.
- Incorporating steel counterweights into trusses or staging platforms themselves.
- Selecting denser materials (for example, steel instead of aluminium in lower members) to keep the centre of gravity low.
By designing more of the stabilising weight into the structure itself, you reduce the need for external concrete blocks and streamline bump-in and bump-out operations.
2. Reduce Wind Catchment Area
Wind force is directly proportional to exposed surface area.
Reducing the surface area exposed to the wind will immediately decrease the design wind pressures and the resulting ballast demand.
Ways to achieve this include:
- Using vented or mesh banners rather than solid panels, which allow wind to pass through.
- Minimising decorative elements that unnecessarily increase wind exposure.
- Designing open-frame structures with larger perforations to encourage airflow.
In simple terms: the less the wind "catches" your structure, the less force you need to resist and the less ballast you’ll require.
3. Optimise Geometry for Stability
The geometry of your structure plays a massive role in how much ballast is needed.
As outlined under AS/NZS 1170.0:2002 (General Principles), increasing a structure’s stability through a wider base or lower centre of gravity enhances resistance against overturning moments.
Techniques include:
- Expanding base widths using outriggers or spreader beams.
- Introducing triangulated bracing to prevent racking and sway.
- Concentrating mass low in the structure to improve overall stability.
Wider, heavier, and stiffer designs require less ballast to achieve the same resistance compared to narrow, tall, or flexible ones.
4. Use Interconnected Structures
Connecting temporary structures together increases their collective stability effectively spreading wind loads and reducing ballast needs on individual elements.
This approach follows the same structural logic outlined in AS 4687:2007 (Temporary Fencing and Hoardings), which outlines that stability improves when elements are braced and connected.
Practical options include:
- Linking adjacent truss towers with cross-bracing.
- Tying stages to fencing, lighting towers, or adjacent rigging frames.
- Designing activation layouts that allow elements to act together structurally.
Rather than each element requiring separate ballast to resist tipping, interconnected structures can work together greatly reducing individual ballast demands.
5. Rationalise the Wind Design Criteria
Rather than designing for maximum theoretical wind speeds, a site-specific, risk-managed design approach can dramatically reduce ballast requirements.
This is supported under AS/NZS 1170.2:2021, where site-specific factors like terrain category, shielding, and operational measures can influence the appropriate design wind speeds.
Key methods include:
- Setting a maximum operational wind speed limit (e.g., event closure or structure removal above 60 km/h).
- Preparing a Wind Management Plan with a qualified structural engineer outlining procedures for monitoring and action during weather events.
- Accounting for actual site shielding—such as nearby buildings or trees—that reduce local wind effects.
By rationalising the design pressures based on realistic site conditions and operational controls, you can engineer the structure to safely require much less ballast, as wind pressure is directly proportional to wind speed.
Quickly Estimate Your Ballast Requirements
If you want a fast way to estimate how much ballast your temporary structure might need, try our free Ballast Calculator.
It’s a handy tool designed for event managers, designers, and builders to get a quick indication based on structure size, wind loads, and event conditions.
👉 Use the Ballast Calculator here
Whether you're early in design or double-checking an activation layout, the calculator can help you plan smarter from the start.
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