How Many Fence Slats Per Metre?

How We Calculated This

Close-board (featheredge) fencing is built from tapered slats that overlap each other, so each slat covers less than its full width. The effective cover per slat is the board width minus the overlap:

• Effective cover: 100mm board − 25mm overlap = 75mm per slat
• Slats per metre: 1000 ÷ 75 = 13.3 slats (round up to 14 when ordering)
• Slats per 2.4m bay (post to post): 2400 ÷ 75 = 32 slats

For a full fence, work bay by bay and round up. A 10m run with posts at 2.4m centres needs 10 ÷ 2.4 = 4.2, rounded up to 5 bays (6 posts):

• Slats needed: 5 bays × 32 slats = 160 slats
• With 10% wastage: 160 × 1.10 = 176 slats

A 5–10% wastage allowance covers split, warped or damaged boards — 10% is the standard figure for featheredge because thin tapered boards split easily when nailed near the edge.

Slats Per Metre by Board Width

UK featheredge boards are sold in three standard face widths. With the standard 25mm overlap, the formula is: slats per metre = 1000 ÷ (board width − overlap).

• 100mm (4in) board: covers 75mm — 13.3 per metre (order 14), 32 per 2.4m bay
• 125mm (5in) board: covers 100mm — 10 per metre, 24 per 2.4m bay
• 150mm (6in) board: covers 125mm — 8 per metre, 20 per 2.4m bay

Wider boards need fewer fixings and go up faster, but the slat count does not fall as much as you might expect because the overlap stays the same 25mm whatever the board width.

Why the Overlap Matters

The overlap is not decorative — sawn boards shrink across their width as they dry out in summer. A 25mm lap keeps the fence private and windproof even after seasonal shrinkage; skimp on it and gaps open up within the first year. 25mm is the figure most UK fencing suppliers specify, though some manufacturers use slightly less on factory-built panels (Jacksons Fencing, for example, laps its 100mm pales by 20mm). Close-board fencing itself is specified in BS 1722-5, which covers boards lapped over arris rails with a gravel board at the bottom and an optional capping rail on top.

Practical Tips

• Count slats per bay and round up each bay, not across the whole run — part-slats can’t be shared between bays
• Always fit a gravel board at the bottom — featheredge slats rot quickly in ground contact, and replacing a gravel board is far cheaper than reboarding the fence
• Fix with hot-dip galvanised nails into 2 arris rails for fences up to 1.2m, 3 rails for 1.5m and taller
• Keep the fence at 2m or under — in England a fence over 2m high (or over 1m next to a highway used by vehicles) needs planning permission
• Set the thick edge of each new slat over the thin edge of the last, and check the lap with a 25mm gauge block every few boards so the spacing doesn’t drift