Scaffold Board Calculator — Platform Width, Boards & Toe Boards

Minimum platform widths per TG20 and BS EN 12811: 3 boards (675mm) — access and inspection only. 4 boards (900mm) — painting, light work, foot traffic. 5 boards (1125mm) — bricklaying, general purpose (most common). 6+ boards — heavy duty, material storage. Most working scaffolds use 5 boards to allow space for workers, materials, and a walkway.

Toe boards (≥150mm high, BS EN 12811-1) are required at any platform edge where tools or materials could fall and cause injury — in practice the outer (facade) edge of every working platform plus open ends. The inner (building-side) edge needs a toe board only where the gap to the structure is 225mm or more, or there are openings a person could fall through (NASC SG29). The Work at Height Regulations 2005 duty is risk-based rather than a fixed 2m trigger, but a working scaffold is normally fitted with full collective edge protection: a top guardrail at ≥950mm, an intermediate guardrail so no gap exceeds 470mm, and a toe board.

Standard UK scaffold boards come in 1.5m, 1.8m, 2.4m (8ft), 3.0m (10ft) and 3.9m (13ft) lengths, with 3.9m the most common. Boards lie ALONG the bay and rest across transoms — they are not cut to a single bay, so longer boards run continuously over several bays and lap at transoms. A 38mm board may span a maximum of 1.5m between transoms if machine stress graded, or 1.2m if visually graded (BS 2482:2009). Each end should overhang its end transom by at least 50mm and no more than 150mm (about 4× the 38mm thickness); never less than 50mm or it can tip.

Scaffold boards must be inspected before first use, after any event likely to affect their strength, and at least every 7 days as part of the scaffold inspection (Work at Height Regulations 2005 reg 12). Check for: splits or cracks, rot (especially at bearing points), warping, missing or damaged end bands, and excessive wear. Under BS 2482:2009 a board is rejected if a fissure (split/shake) is 12mm or more deep AND more than 225mm long (one board width), if wane exceeds 25mm on the face or 12mm on the edge, or for loose/broken knots, end-band damage, decay or distortion beyond the standard’s limits. The often-quoted ‘reject a knot over one-third of the board width’ is a practical site rule of thumb, not a BS 2482 limit — when in doubt, destroy the board.

Scaffold boards are sawn softwood timber, 225mm × 38mm × 3.9m (standard), graded to BS 2482 and banded at each end. Staging boards are wider (225-450mm) and thicker, used for longer spans. Lightweight composite boards (aluminium/plywood) are increasingly used as alternatives — they are lighter, more durable, and don't absorb water.