Unsecured scaffold boards are one of the most common causes of falls from height on New Zealand worksites and around the home. The good news is that with the right techniques — correct overhang, proper lapping, board cleats, and firm ties or clips — you can create a stable, safe working platform. Here is what you need to know before you step onto any scaffold.
Why Board Security Matters
A scaffold board that slips sideways, tips, or bounces underfoot can throw you off balance in an instant. Falls from height are a leading cause of serious injury and death in New Zealand. WorkSafe NZ sets out clear requirements for working at height, and these apply whether you are a professional scaffolder or a homeowner erecting a light-duty platform. Even a fall from one metre can cause life-changing injuries, so getting board security right is non-negotiable.
Choose the Right Boards
Before worrying about how boards are fixed, make sure you are starting with the right material:
- Timber scaffold boards should be free of large knots, splits, or warping. In NZ, scaffold-grade timber is typically 225 mm × 38 mm (nominal) and should comply with the relevant grading standard.
- Aluminium or LVL (laminated veneer lumber) boards are also widely used and tend to be more dimensionally stable.
- Never use general framing timber, pallet timber, or untreated fence boards as scaffold planks — they are not rated for the load.
- Inspect every board before use. Discard any that are cracked, badly warped, or have significant rot.
The Golden Rules of Board Placement
1. Correct Overhang (Cantilever)
Each board must overhang its end support (transom or ledger) by a minimum of 150 mm and a maximum of four times the board thickness — typically no more than about 150 mm for standard 38 mm boards. Too little overhang and the board can tip like a seesaw; too much and it becomes a trip hazard or can spring up when you step near the end.
2. Minimum Bearing Length
Every board must rest on at least two supports. The bearing (contact) length on each support should be a minimum of 100 mm so the board cannot rock or slide off the transom.
3. Lapping Boards End-to-End
When boards need to be joined end-to-end along the platform:
- Lap them over a transom by at least 300 mm on each side of the joint.
- Never butt boards end-to-end in mid-air with no support beneath the joint.
- Stagger joints so not all boards break at the same transom.
4. Board Width and Coverage
The working platform should be wide enough for the task. As a general guide:
| Platform use | Minimum width |
|---|---|
| Foot traffic / light work | 450 mm (2 boards) |
| General building work | 675 mm (3 boards) |
| Bricklaying or heavy materials | 900 mm+ (4+ boards) |
Leave no gaps wider than 25 mm between boards — a gap any larger can trap a boot heel.
How to Stop Boards Slipping and Tipping
Cleats (Timber Stops)
The simplest and most traditional method is to nail or screw a cleat — a short offcut of timber — across the underside of two or more boards at each end. The cleat sits tight against the inside face of the transom, preventing the boards from sliding outward. Use at least two fixings per board into the cleat.
Scaffold Board Clips and Hooks
For tube-and-fitting or system scaffold, purpose-made board retaining clips (sometimes called board hooks or transom clips) grip the transom tube and hold the board down. These are the preferred method on most modern scaffolds because they resist both sliding and uplift (boards lifting in wind). Make sure clips are rated for the board size you are using and are fully engaged before loading the platform.
Lashing and Tying
On lighter or temporary platforms, boards can be lashed to the transom with scaffold wire, tie wire, or purpose-made straps. Tie each board individually — do not rely on one tie to hold multiple boards. Check ties after any significant wind event or vibration.
Anti-Slip Surfaces
Even well-secured boards can be slippery when wet — a real concern in the New Zealand climate. Options include:
- Non-slip strips stapled or adhered across the boards at regular intervals.
- Chicken wire or mesh tacked to the surface for grip.
- Keeping boards swept clear of sawdust, paint drips, and debris.
Guardrails and Toe Boards
Securing the boards themselves is only part of the picture. Any platform 900 mm or more above the ground should have:
- A top rail at approximately 1 m height.
- A mid rail at approximately 500 mm.
- A toe board (kick board) at least 150 mm high along the open edges to stop tools and materials rolling off onto people below.
Refer to WorkSafe NZ guidance on working at height for the full requirements.
Building Consent and Licensing
For most residential DIY scaffolding, a building consent is not required under Schedule 1 of the Building Act — but always confirm with your local council, as rules can vary. Scaffolding on commercial sites or above certain heights may have additional requirements; check with WorkSafe NZ and your council for current rules. Check MBIE Building Performance for guidance on what work requires consent or a licensed tradesperson.
When to Call a Professional
Call a qualified scaffolder if:
- The platform will be higher than 5 metres.
- You are working on a steep or complex roof.
- The scaffold needs to support heavy materials (tiles, concrete blocks, etc.).
- You are unsure about any aspect of the setup — a mistake at height can be fatal.
You can find licensed local scaffolders on tradedirectory.co.nz. A professional will ensure your scaffold meets NZ standards and give you peace of mind.
