GardenCalcs.uk
Gravel Board Calculator — Fence Base Protection
Calculate gravel boards needed to protect fence panels from rot.
Total run of the fence in metres — one gravel board spans each post-to-post bay along the bottom.
Width of each fence bay — UK standard is 1.83 m (6 ft); gravel boards are made to match this length.
Extra boards for cuts and breakages (default 5%)
Number of fixing clips per board (default 2)
Optional: price per board to estimate total material cost (default 0)
How We Calculate This
Boards = Fence Length ÷ Panel Width, rounded up so every post-to-post bay gets one board (UK standard bay = 1.83 m / 6 ft). A wastage allowance (default 5%) adds spare boards for cuts and breakages. Clips default to 2 per board — one at each post end — and the count is adjustable in the advanced options for exposed sites.
Frequently Asked Questions
Boards sitting between ground and fence panels, protecting panels from moisture and rot. Usually 150mm high.
Concrete lasts much longer and is worth the extra cost. Timber boards are cheaper but rot over time.
Yes — gravel boards fix to the posts with galvanised clips (also called gravel board brackets). Typically 2 per board, one at each post end; this calculator defaults to 2 but you can raise it to 3–4 per board for exposed or windy sites in the advanced options.
A gravel board is a horizontal board fitted between fence posts at ground level, below the fence panels. It protects the panels from ground moisture, rot, and soil contact.
Concrete gravel boards last much longer and will not rot. They are heavier and slightly more expensive but are a worthwhile investment for long-term fencing.
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Last updated: February 2026
All calculations are estimates based on standard gardening guidelines. Results may vary with soil conditions, climate, and plant varieties.