Fencing is priced by the panel and sold by the panel, but the boundary is measured in metres, and those two do not divide evenly. A sixty-metre run at 1.8-metre panels is thirty-three panels and change, which means thirty-three paid for and a partial one cut down — or, if you are unlucky about where the corners fall, thirty-three plus a whole panel used to make a half-metre infill. This unfolds the run into a straight line, marks every panel joint and every post, and counts the gates separately, because a gate is the one place where the panels stop and the posts start doing structural work.
Boundaries, panels and posts
Panels are a fixed width. The run rarely is. That gap is where the cost hides.
Walk the boundary with a tape. Follow the ground.
Leave at zero if the boundary has three sides.
Standard panel widths are 1.8 m and 2.4 m.
Posts usually land at every panel joint and no more than 2.4 m apart.
Result
The run is measured on the ground, not on the plan
The first mistake in fencing is taking the boundary length off a plan or a deed. Plans are drawn to a scale and a scale flattens: a boundary that steps, that follows a hedge line, or that climbs a slope is longer on the ground than it is on paper. Walk it with a tape or a measuring wheel, along the line the fence will actually take, and add the sides separately rather than trying to hold one long measurement.
On sloping ground the horizontal distance and the sloping distance differ, and which one matters depends on how the fence is erected. Stepped panels follow the slope and need the sloping length, which is longer. Panels set level with a stepped base need the horizontal length plus the extra height at the low end. On a noticeable slope the difference is worth a panel.
Why the last panel is the expensive one
Panels are manufactured at a fixed width and they are not designed to be cut. Cutting a panel down means cutting through rails and losing the joinery that holds it together, so the usual practice is to buy the full panel, cut it, and cap the cut end with a batten — or to accept a slightly narrower final bay and adjust the post position to suit. Either way the whole panel is paid for.
The alternative is to move the posts. Rather than setting them at fixed centres and letting the last bay fall where it falls, set out the run from the gate or the corner and adjust the spacing slightly so the bays come out even. Spreading a hundred millimetres across eight bays is invisible; a four-hundred-millimetre infill bay is not. This is the single cheapest adjustment on a fencing job and it costs nothing but five minutes with a tape before digging.
Posts: where the strength actually comes from
A fence fails at the posts long before it fails at the panels. The panel is a sail and the post is the mast, and the standard post spacing of 1.8 to 2.4 metres is a wind loading figure rather than a convenience. On an exposed site, or with closeboard or solid panels that catch more wind than hit-and-miss, close the spacing toward 1.8 m and go deeper with the holes.
Post depth is the other half. A 1.8-metre panel needs a post set at least 600 millimetres in the ground, concreted, and the concrete should be domed away from the post so water runs off rather than sitting against the timber. Posts at corners, at gates and at any change of direction carry load in two directions and want to be heavier and deeper than the line posts.
A gate hangs its entire weight on one post and levered at that, so gate posts should be heavier than line posts and set deeper — 750 mm or more.
Allow two extra posts per gate and a gate width of about a metre for a pedestrian gate and three metres for a vehicle one. The gate is also the place where the run stops being panels.
| Fence type | Panels per 10 m | Posts per 10 m | Note |
|---|---|---|---|
| 1.8 m lap panel | 5.6 | 5.2 | The standard domestic option |
| 2.4 m lap panel | 4.2 | 4.2 | Fewer posts, heavier panels |
| Closeboard | n/a | 5.6 | Built on site, priced by the metre |
| Hit-and-miss | 5.6 | 5.2 | Lets wind through, survives exposure |
| Picket, 1.8 m | 5.6 | 5.2 | Decorative, low wind loading |
| Post and rail | n/a | 3.3 | Agricultural, wide spacing |
A worked example
- Walk the boundaryTwelve, eighteen, twelve and eighteen metres gives 60 m of run.
- Take off the gateOne pedestrian gate at a metre leaves 59 m to be panelled.
- Divide by the panel widthFifty-nine at 1.8 m is 32.8, so 33 panels — with 0.4 m cut off the last one.
- Count the postsSixty metres at 2.4 m centres is 25, plus one to close the run, plus two at the gate: 28 posts.
- Price itThirty-three panels at $65, twenty-eight posts at $18 and a gate at $85 comes to $2,734, or $45.57 per metre of run.
Forty-five dollars a metre is a useful benchmark for a domestic lap-panel fence with concreted posts. Anything much below it is usually thinner timber or shallower posts; anything much above it is usually closeboard, a better gate, or difficult ground.
Ground conditions and the bits nobody prices
The line items people forget are the ones that are neither panels nor posts: post concrete, gravel boards at the base of timber panels, capping rails, and the fixings. A gravel board is worth having wherever panels meet the ground, because it keeps the panel out of standing water and is far cheaper to replace than the panel above it.
Ground conditions change everything. Digging into clay is slow; digging into ground with roots or rubble in it is slower; hitting a service is a different kind of expensive. If the run crosses a soakaway, a drain run or an old foundation, the post positions have to move, and moving a post position moves the panel layout with it.
Boundary ownership is worth establishing before any of this. In many places the fence line is not the legal boundary, and the legal boundary is not where the previous fence stood. Where the position matters, the garden area figure gives you the enclosed area to check against the title plan, and a boundary survey is far cheaper than moving a fence twice.
Do
- Walk the boundary with a tape and add the sides separately.
- Set out from the gate or a fixed corner and even up the bays.
- Set gate posts deeper and heavier than line posts.
- Close the post spacing on exposed sites and with solid panels.
- Add gravel boards, concrete, capping and fixings as separate lines.
Avoid
- Taking the boundary length off a plan or a deed.
- Setting posts at fixed centres and accepting a sliver as the last bay.
- Setting posts shallower than 600 mm in soft ground.
- Assuming the old fence line is the legal boundary.
- Forgetting that a gate needs two posts and stops the panel run.
Where the numbers stop being true
The run is treated as straight-line segments. Curves are approximated by chords, which under-measures: a curved boundary walked with a tape between two points is shorter than the same boundary measured in short steps around the curve. On a tight curve, take several short measurements rather than one long one.
Panels are assumed to be cuttable, which lap panels are and some framed panels are not. If the product cannot be cut, the last bay has to be a made-up infill, and the material figure goes up while the panel count stays the same.
No allowance is made for changes in level beyond the note above, and none for removing the old fence, which is a day's labour and a disposal charge. Nor is there any allowance for the panels that arrive damaged — with timber, order one spare on a long run. If the boundary is being planted rather than fenced, the hedge planting figure and the drip line length are the two numbers that follow.
How the figures are produced
The four sides are added to give the total run. Gate openings are subtracted to give the length that is actually panelled, and that length is divided by the panel width and rounded up to whole panels — the difference between what the panels cover and what is needed is the cut. Posts are counted at the spacing you entered across the full run, plus one to close it and two per gate. Cost is panels, posts and gates at their respective prices, and the per-metre figure is the total divided by the run.
Questions people ask
Why do I need more posts than panels?
Because posts sit at every joint plus one to close the run, and because gates need two each. On a sixty-metre run with 1.8 m panels and 2.4 m posts you get 33 panels and 28 posts.
Can I cut a fence panel down?
Lap panels, yes, with a batten capping the cut end. Framed panels with a rebated frame, generally not — buy an infill kit or adjust the post positions instead.
How deep should posts go?
At least 600 mm for a 1.8 m panel, more for taller panels, gate posts and exposed sites. Concrete them and dome the concrete away from the post.
Should I close the spacing on an exposed site?
Yes. Solid panels act as sails. Going from 2.4 m to 1.8 m centres roughly halves the load on each post.
What about a sloping boundary?
Stepped panels need the sloping length; level panels need the horizontal length plus extra height at the low end. Measure the way you intend to build.
Do I need gravel boards?
Wherever timber meets the ground. They keep the panel out of standing water and are much cheaper to replace than the panel above.