Close Board Fencing Calculator — Featheredge Slats & Materials

Using standard 100mm (4 inch) featheredge boards with a 25mm overlap, the effective (exposed) width is 75mm, so boards per metre = 1000 ÷ 75 ≈ 13.3 — about 13 boards per metre run of fence. For 125mm boards (100mm effective), you need about 10 per metre, and 150mm boards (125mm effective) about 8 per metre. Always add 10% for wastage and damaged boards.

Close board (featheredge) fencing is stronger and longer-lasting than panel fencing. Individual boards can be replaced without removing whole sections. It handles wind better as air passes between slight gaps. It's more expensive to install but is the professional choice for permanent boundaries.

Use 2 arris rails for fences up to 1.2m (4ft) tall, and 3 arris rails for fences 1.5m (5ft) and above. Rails should be evenly spaced: for a 1.8m fence with 3 rails, position them at approximately 300mm, 900mm, and 1500mm from ground level.

Yes, gravel boards are strongly recommended. They sit between the posts at ground level, keeping the featheredge boards off the damp ground. This prevents rot and extends the fence's life significantly. They're inexpensive and easy to replace if they rot — much cheaper than replacing fence boards.

Standard fence posts for close board fencing are 75mm x 75mm (3 x 3 inch) or 100mm x 100mm (4 x 4 inch) for taller fences. Post length should be fence height plus 600mm (2ft) for burying in the ground. For a 1.8m fence, use 2.4m posts. Always use treated (tanalised) timber.

Divide your fence run into bays (posts at 2.4m centres as standard), then divide each bay width by the effective cover of one slat — the board width minus the 25mm overlap. A standard 100mm featheredge slat covers 75mm, so a 2.4m bay takes 2400 ÷ 75 = 32 slats. Multiply by the number of bays and add 10% for wastage: a 10m run at 2.4m centres is 5 bays × 32 = 160 slats, or 176 once wastage is added. Enter your fence length, board width and post spacing above and the calculator rounds each bay up for you.

Close board (featheredge) fencing typically costs £60 to £120 per metre supply and installed in the UK, depending on board width, fence height, ground conditions and local labour rates. FenceInstallers.co.uk's 2026 UK pricing puts feather edge fencing at £42.66 per metre for materials alone and £61.32 per metre installed, based on runs of 15 metres or more. MyJobQuote's 2026 guide gives a broader UK average of £110 to £120 per metre for a typical garden fence including labour, with individual close board panels costing £45 to £65 to supply and £50 to £80 in labour each. Close board is the standard solid privacy fence in the UK, taller and sturdier than open designs, so expect it to sit above basic panel fencing on price. This calculator's optional Price Per Slat field estimates the featheredge boards only; add posts, arris rails, gravel boards, postcrete and labour on top for a full job total.

Ready-made close board fence panels are a different product from the board-by-board fencing this calculator quantifies. Panels are built off-site to a fixed width, usually 1.83m (6ft), so you buy the panel as a unit rather than counting individual boards. Applying this calculator's own formula (board width minus the 25mm overlap) to a 1.83m-wide panel gives approximately 25 boards from 100mm featheredge, 19 boards from 125mm featheredge, or 15 boards from 150mm featheredge, since a wider board covers more face width per fixing. Manufacturers rarely publish an exact board count and it varies slightly by supplier. If you are buying pre-made panels rather than building board by board, use our fence panel calculator to work out panels, posts and postcrete instead.

25mm is the industry-standard overlap for featheredge boards of any width, 100mm, 125mm or 150mm, and it is the default this calculator uses. It is what most UK fencing contractors and timber merchants specify, and matches the effective coverage figures used throughout this page (75mm, 100mm and 125mm respectively). 18mm is the commonly quoted minimum among UK suppliers; below that, gaps can open up as the boards shrink in summer. At least one major supplier recommends a little more for wider 150mm boards, around 30mm, to keep a similar proportion of cover to width. Too little overlap and gaps appear within a year as the timber dries out; too much wastes boards for no extra privacy. You can change the default in this calculator's Advanced Options if your boards or supplier specify a different figure.

At the standard 2.4m post spacing, close board fencing needs roughly 1 post and 1 gravel board every 2.4m of run (0.42 of each per metre on a long fence), plus 2 to 3 arris rails per 2.4m bay depending on height, which works out to about 0.83 rails per metre up to 1.2m tall and 1.25 rails per metre at 1.5m and above. Worked example for a 10m run at 1.8m high with 2.4m post spacing: 5 bays means 6 posts, 5 gravel boards, 15 arris rails (36m of rail in total), and 12 bags of 20kg postcrete at 2 bags per post. Widen the post spacing to 3.0m and the same 10m run needs only 4 bays, 5 posts and 4 gravel boards, at the cost of a stiffer, more expensive rail run to span the wider bay. Use our gravel board calculator and concrete for fence posts calculator to work out those materials on their own.