NZ TIMBER EDITORIAL GUIDE
Fence Post Spacing NZ
For a straight residential paling fence, 2.4 m centres are a useful planning starting point—not a universal design rule. The finished layout must also suit rail lengths, fence height, wind exposure, gates, corners, ground conditions and any project-specific design.
What ‘post spacing’ actually measures
Post spacing is normally stated centre-to-centre: the distance from the centreline of one post to the centreline of the next. A 2.4 m bay therefore does not mean a 2.4 m clear opening. The post thickness occupies part of that distance, and rails may be face-fixed, halved over the post, or cut between posts.
The set-out should begin with fixed points. Mark boundary ends, changes of direction, gate openings and any location where the fence meets a building or retaining wall. These are post positions before the intermediate bays are divided. If the whole boundary length is divided first, a gate or corner often leaves one short, awkward bay at the end.
The five things that can shorten a bay
| Factor | Why it affects the set-out | Planning response |
|---|---|---|
| Fence height | A taller face catches more wind and increases post and rail demand. | Confirm the complete fence system; do not copy spacing from a low fence. |
| Rail size and orientation | A rail spanning flat behaves differently from the same section fixed on edge. | Match centres to the specified rail and supported joint detail. |
| Paling thickness and layout | Heavy, lapped or double-sided cladding adds weight and wind area. | Treat the cladding pattern as part of the system. |
| Exposure and ground | Open coastal sites, hilltops, soft fill and wet ground can change performance. | Seek project advice and reduce centres only as part of a coherent detail. |
| Gates and corners | Hinges, latches and changes of direction place concentrated loads on posts. | Use dedicated gate/end/corner posts; do not count them as ordinary intermediates. |
The Ministry of Education’s public school-fencing guidance uses approximately 2.4 m centres for a particular close-boarded timber specification, with 100 × 100 mm posts, three 100 × 50 mm rails and site checks for wind and ground. Kāinga Ora also publishes different member arrangements for 1.2 m and 1.8 m fences. Those documents are useful evidence that spacing belongs to a whole assembly, not a single magic number.
Post-count formula for one straight run
Choose a maximum planning bay, divide the clear run by that value, and round the number of bays up. For a run with a post at both ends:
After rounding the bay count, divide the length by the new whole number of bays. That produces even centres no greater than the target. Count gate, corner and termination details separately; a gate opening may require two posts and splits the boundary into two independent runs.
| Straight run | Target maximum | Whole bays | Even centres | Base post positions |
|---|---|---|---|---|
| 12 m | 2.4 m | 5 | 2.40 m | 6 |
| 18 m | 2.4 m | 8 | 2.25 m | 9 |
| 24 m | 2.4 m | 10 | 2.40 m | 11 |
| 30 m | 2.4 m | 13 | about 2.31 m | 14 |
The 18 m example is the useful one: 18 ÷ 2.4 = 7.5. Seven bays would exceed the planning maximum, so round to eight bays. Nine posts then form eight equal bays at 2.25 m centres.
Corners, gates and stepped ground change the arithmetic
- Treat each straight boundary segment between corners as its own run.
- At a pedestrian or driveway gate, establish the exact opening and hardware arrangement before dividing the remaining fence.
- A corner post may serve the end of two runs, so do not automatically count it twice in the final order.
- On sloping ground, decide whether the rail and paling tops follow the contour or step in levels. Stepped bays may need different post lengths and create offcuts.
- Avoid moving a post off a stable set-out merely to use every millimetre of a stock rail. A cut plan should follow the approved layout, not dictate it.
Rail stock length still matters economically. A 4.8 m rail can often cover two 2.4 m bays when joints are supported at the post and the fixing detail allows it. At 2.25 m centres it may produce useful offcuts; at irregular centres it may create more waste. Record the intended cuts before ordering rather than simply buying total lineal metres.
Turn the set-out into an order list
- Draw every fixed post position and number the remaining bays.
- Select the fence-system assumptions: height, post section, rail section, number of rail rows and paling arrangement.
- Calculate posts from positions, rails from rows × run length, and palings from effective cover.
- Add separate gate posts, corner details, concrete, fixings and a realistic cutting allowance.
- Ask the supplier to confirm lengths, treatment, grade where specified, freight and current availability.
The Timber Dealers fence calculator can turn a settled layout into a first quantity schedule. It does not decide whether the layout is structurally suitable. Compare H4 fence-post families, H3.2 rails and palings as separate products because ground-contact exposure and above-ground exposure are different purchasing decisions.
Corners, ends and gates deserve different posts
A straight intermediate post, a corner post and a gate post do not have the same job. Corners receive loads from two directions; gates apply weight and repeated movement. The design may change post section, embedment, concrete and bracing even where field spacing stays constant.
- List gate leaf width and hardware before locating posts.
- Provide clearance for latches, stops and ground movement.
- Confirm whether rails meet on a post face or use another connection.
- Check boundary set-out and survey information before digging.
- Keep post holes clear of identified underground services.
Post count arithmetic should therefore separate intermediate, end, corner and gate posts. Pricing them as one generic H4 size can hide the highest-consequence substitution in the fence.