What are gravel boards?

Boards sitting between ground and fence panels, protecting panels from moisture and rot. Usually 150mm high.

Concrete or timber gravel boards?

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.

What is a gravel board?

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.

Are concrete gravel boards better than timber?

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.

GardenCalcs

Gravel Board Calculator — Fence Base Protection

Calculate gravel boards needed to protect fence panels from rot.

Fence Length

Total run of the fence in metres — one gravel board spans each post-to-post bay along the bottom.

Panel Width

Width of each fence bay — UK standard is 1.83 m (6 ft); gravel boards are made to match this length.

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

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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.