Securing scaffolding on a sloped section is more complex than setting it up on flat ground, and getting it wrong can be genuinely dangerous. In New Zealand, scaffolding work is governed by strict health and safety regulations, and for most residential projects over a certain height, you'll need a competent — and often licensed — scaffolder to do the job safely and legally.
Why Sloped Ground Makes Scaffolding Trickier
On a flat site, scaffold standards (the vertical poles) sit level and load is transferred straight down into the ground. On a slope, each standard is at a different height relative to the ground, which means uneven load distribution, a higher risk of the scaffold shifting or toppling, and more complex bracing requirements. New Zealand's varied terrain — from steep Wellington hillsides to sloping Canterbury sections — makes this a very common challenge.
NZ Regulations and Standards You Need to Know
All scaffolding work in New Zealand must comply with the Health and Safety at Work Act 2015 and the associated regulations managed by WorkSafe NZ. The key technical standard is AS/NZS 1576 (Scaffolding) and AS/NZS 4576 (Guidelines for Scaffolding), which set out design, erection, and inspection requirements.
For scaffolding over 5 metres in height, a Certificated Scaffolder (holding a current certificate of competence) must be involved in the erection, alteration, and dismantling. This is not optional — it's a legal requirement under the Health and Safety at Work (General Risk and Workplace Management) Regulations 2016. You can verify a scaffolder's certification through WorkSafe NZ.
For lower scaffolding, a competent person must still supervise the work. "Competent" has a specific meaning under the Act — it's not just anyone willing to have a go.
Step-by-Step: Key Principles for Sloped Sections
1. Assess the Ground Conditions First
Before any scaffold goes up, assess the slope angle, soil type, and stability. Loose, sandy, or recently disturbed soil can shift under load. If the ground is soft or unstable, you may need to:
- Lay scaffold boards or timber sole plates (baseplates) under each standard to spread the load
- Use compacted gravel or concrete pads in extreme cases
- Check for underground services (pipes, cables) before driving any stakes
2. Use Adjustable Base Plates and Screw Jacks
Adjustable screw jacks (also called base jacks) are the standard solution for sloped ground. Fitted to the bottom of each standard, they allow you to level the scaffold frame even when the ground beneath each leg is at a different height. Key points:
- Screw jacks should not be extended beyond the manufacturer's maximum extension — typically around 300–450 mm, but always check the specific product specifications
- The more extended a jack, the less stable it becomes, so minimise extension where possible by stepping the scaffold down the slope in tiers
- Sole plates (timber or steel) must be used under each baseplate on soft ground
3. Step the Scaffold Down the Slope
Rather than trying to span a large height difference with extended jacks, experienced scaffolders step the scaffold — setting each bay at a progressively lower level to follow the slope. This keeps jack extensions minimal and maintains structural integrity throughout the structure.
4. Tie and Brace Thoroughly
On sloped ground, lateral (sideways) forces are greater, so bracing is critical:
- Cross-bracing (diagonal bracing between standards) must be installed at regular intervals as specified in AS/NZS 1576
- Ties to the building (using anchor bolts or through-ties into the structure) are essential — the scaffold must be tied at specified vertical and horizontal intervals
- On very steep slopes, raking tubes (angled braces running from the scaffold into the ground) may be required for additional stability
- Never rely on the scaffold leaning against the building for support
5. Inspect Before Use and Regularly During the Job
Once erected, the scaffold must be inspected by a competent person before first use, after any alteration, after any event that may have affected its stability (such as heavy rain softening the ground), and at regular intervals during the project. Keep a record of inspections.
What Homeowners Can and Cannot Do
As a homeowner, you can erect low-level proprietary scaffold systems (such as mobile tower scaffolds) for minor tasks, provided the scaffold is under 5 metres and you follow the manufacturer's instructions carefully. However, for anything taller, on significantly sloped ground, or attached to your home's structure, you should engage a Certificated Scaffolder. The risks of getting it wrong — injury, property damage, or liability — are simply too high.
Note that scaffolding itself is not typically a building consent trigger, but the work being done (e.g., structural alterations, reroofing) may require consent. Always check with your local council.
When to Call a Professional
You should always engage a qualified, Certificated Scaffolder when:
- The scaffold will exceed 5 metres in height
- The slope is significant or the ground is unstable
- The scaffold needs to be tied into the building structure
- The job involves complex configurations around obstacles
- You're unsure about any aspect of the setup
A professional scaffolder will assess your specific site, design an appropriate system, and take responsibility for its safety. You can find qualified local scaffolders on tradedirectory.co.nz.
