How the Closeboard Fencing Calculator Works

Enter your total fence length, height and preferred post spacing. The calculator divides run into bays, works out posts and rails from the bay count, then calculates featheredge boards from covered length.

The board maths is part worth understanding. Standard 100mm featheredge boards overlap by around 25mm, leaving a 75mm exposed face per board. Dividing your run by 75mm gives board count, which works out at roughly 13 boards per metre of fence. A 10 metre run therefore needs around 130 boards before wastage, plus posts, rails and gravel boards.

The Components of a Closeboard Fence

Each part of a traditional closeboard build does a specific job:

• Posts: 100 x 100mm timber or slotted concrete, set at 1.8m to 3m centres and 600mm into the ground
• Arris rails: the triangular horizontal rails the boards fix to, 2 per bay for fences up to 1.5m and 3 per bay above that
• Featheredge boards: the tapered overlapping boards forming the face, always pressure treated
• Gravel boards: 150mm boards at base keeping the featheredge out of ground moisture, the single biggest factor in how long fence lasts
• Centre stumps: short posts supporting the bottom rail mid bay on traditional 3m bays
• Capping rail: optional but worthwhile, protecting exposed end grain along the top

Fixings run at roughly 2 galvanised nails per board per rail, so a 3 rail fence uses 6 nails per board and postcrete goes in at 1.5 to 2 bags per post depending on ground.

Post Spacing Changes Everything

Two setting out traditions exist and your choice reshapes whole order. Traditional closeboard uses 3m bays with a centre stump supporting the bottom rail, which minimises posts and suits long garden runs. The heavier duty approach uses 1.8m centres, matching concrete gravel board lengths, adding rigidity in exposed gardens and removing the need for stumps.

For windy or elevated sites shorter bay wins comfortably, ideally with an extra rail. Closeboard presents a solid face to wind and fences that fail in winter storms are nearly always ones with over stretched post spacing or shallow post holes.

Worked Example: 15m Run of 1.8m High Fence (3m Bays)

The wastage allowance matters more with featheredge than most materials because boards arrive with occasional splits and warps and cutting into last bay always eats a few.

Height Rules and Longevity

A quick planning note, fences up to 2 metres at a rear boundary are generally permitted development, dropping to 1 metre next to a highway, with extra rules in conservation areas. The common 1.8m closeboard fence sits comfortably inside the limit even with capping.

On lifespan, closeboard done properly outlasts panel fencing by years. The habits that get a fence past 20 years, pressure treated timber throughout, gravel boards keeping every feathered edge board off the soil, posts set 600mm deep in postcrete, rail joints landed on posts and staggered and soil or planting kept from building up against the boards.

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