Ridge Tile Calculator — How Many Ridge Tiles Do I Need?

Our ridge tile calculator determines the number of ridge tiles needed based on the total length of ridge and hip lines, accounting for the standard overlap between tiles. It also calculates mortar or dry ridge kit requirements depending on your chosen fixing method.

The formula

Ridge tiles = Total length (m) ÷ 0.45m (effective cover per tile) × Wastage factor

Standard half-round, angular and universal ridge tiles are 450mm long. Laid end to end with only a small lap, each covers about 0.45m, so you need roughly 2.2 ridge tiles per linear metre. (Traditional 300mm clay ridges are shorter and cover about 0.3m each, giving about 3.3 per metre — change the Effective Cover to 0.3m in Advanced Options for those.)

Fixing methods

• Dry ridge system: Mechanically fixed and compliant with BS 5534:2014. One kit covers ~6m (e.g. Manthorpe or Klober 6m kits).
• Mortar bedding: Traditional bedding, an indicative ~1 bag of sand+cement per 3-5m of ridge. Under BS 5534:2014 it must still be combined with mechanical fixing.

BS 5534:2014 (the British Standard code of practice for slating and tiling, mandatory after a transition period from March 2015) requires all ridge and hip tiles to be mechanically fixed — mortar can no longer be the sole fixing. Dry ridge systems are now the usual choice for UK roofs, offering reliable wind-uplift resistance and longevity.