Levelling scaffold frames on an uneven concrete driveway is one of the most common challenges for DIYers and tradespeople alike. The good news is that with the correct equipment — particularly adjustable screw jacks and sole boards — you can achieve a safe, stable platform even when the surface beneath you isn't perfectly flat. That said, scaffolding is classified as a high-risk structure under NZ law, so understanding the rules before you start is essential.
Why Levelling Matters So Much
An unlevel scaffold is an unsafe scaffold. If frames are not plumb and level, the entire structure can rack (lean sideways), connections can work loose, and the risk of collapse increases significantly. Even a small slope across a concrete driveway — say 20–30 mm over a couple of metres — is enough to cause problems if it isn't properly compensated for. WorkSafe NZ sets out clear requirements for scaffold stability, and levelling is a fundamental part of meeting those requirements.
Equipment You'll Need
Before you start, gather the following:
- Adjustable screw jacks (base jacks) — these thread into the bottom of each scaffold standard (upright) and allow you to raise or lower each leg independently
- Base plates — flat steel plates that sit under each screw jack to spread the load
- Sole boards — timber boards (typically 50 mm thick hardwood or LVL, at least 200 mm wide) placed under base plates on softer or uneven ground; on concrete they are still good practice
- Spirit level (1.2 m or longer) and a line level or laser level
- Tape measure
- Scaffold frames, cross braces, and guardrails appropriate for your job height
You can find scaffold hire and purchase options at Bunnings or Mitre 10, or through specialist scaffold suppliers.
Step-by-Step: Levelling Your Scaffold Frames
1. Assess the Slope
Before erecting anything, walk the driveway and measure the variation in height across the area where the scaffold will stand. Use a long spirit level or a laser level to find the highest and lowest points. This tells you how much adjustment your screw jacks need to provide.
2. Check Your Screw Jack Capacity
Most standard screw jacks have a maximum extension of around 300–450 mm, but never extend a screw jack more than one-third of its total thread length without additional bracing or engineering advice. Overextended jacks dramatically reduce the load capacity of the scaffold. Check the manufacturer's specifications for the exact limit.
3. Position Sole Boards and Base Plates
Even on concrete, place sole boards under each base plate. Concrete driveways can have surface irregularities, expansion joints, or cracked sections that create point loading. A sole board distributes the load more evenly and helps prevent the base plate from rocking.
4. Set the Highest Point First
Start at the highest point of the driveway. Set that screw jack to its minimum extension (nearly fully wound in). This becomes your reference point. All other jacks will be wound out to compensate for the lower ground elsewhere.
5. Adjust Remaining Jacks
Erect the first frame at the reference point, then work along the scaffold run. Use your spirit level across the top of the frames and adjust each screw jack until the ledgers (horizontal tubes) are level in both directions — along the scaffold and out from the wall. Check plumb on the standards using your spirit level.
6. Install Cross Braces and Ties
Once frames are level and plumb, fit all cross braces as you go — never leave frames standing without bracing. If the scaffold is more than one bay high or within reach of a structure, install wall ties according to the scaffold manufacturer's guidelines and WorkSafe NZ requirements.
7. Install Guardrails and Toe Boards
For any working platform above 2 metres, guardrails are mandatory under NZ law. Fit top rails (at the height required by the manufacturer's specifications and WorkSafe NZ requirements) and mid-rails, plus toe boards to prevent tools or materials falling onto people below.
Key NZ Safety Rules to Know
| Requirement | Detail |
|---|---|
| Working at height above 2 m | Guardrails and toe boards required |
| Screw jack extension | Do not exceed manufacturer's limit (typically one-third of thread) |
| Maximum platform load | Check frame rating — do not overload |
| Scaffold over 5 m high | Must be designed and supervised by a Certificated Scaffolder |
| Inspection | Inspect before each use and after any incident or high winds |
For scaffolding over 5 metres in height, New Zealand regulations require the work to be carried out under the supervision of a Certificated Scaffolder. This is a legal requirement, not just a recommendation. Check WorkSafe NZ for the full details on scaffolding regulations.
Common Mistakes to Avoid
- Stacking timber offcuts or bricks under base plates instead of using proper screw jacks — this is dangerous and non-compliant
- Ignoring expansion joints or cracked concrete beneath base plates
- Extending screw jacks too far without additional bracing
- Failing to re-check level after loading the platform with materials
- Not tying the scaffold to the building when required
When to Call a Professional
If your scaffold needs to be higher than 5 metres, sits on ground with significant variation (more than your screw jacks can safely handle), or you're unsure about load ratings and tie requirements, call a qualified scaffolder. A professional will assess the site, select the right equipment, and ensure the structure complies with NZ regulations. You can find licensed local scaffolders on tradedirectory.co.nz. For complex or large projects, an engineer's input may also be required. The BRANZ website has useful guidance on construction safety and best practice.
