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Roof Ridge Calculator

Calculate tiles, mortar, or dry-fix kits for a professional UK finish.

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Material Summary

UK Regs Note: Since 2014, BS 5534 requires that all ridge tiles must be **mechanically fixed**, even if they are wet-bedded with mortar. Dry-fixing systems are now the industry standard for new builds.

Ridge Roofing: Systems, Safety & Standards

Storm Proofing Your Roof

The ridge is the most exposed part of any roof. In the UK, high winds can create a 'suction' effect that lifts ridge tiles off. This is why the industry has shifted away from simple mortar bedding towards mechanical fixing.

Whether you are using a traditional **wet-bedded ridge** or a modern **dry-fix system**, our calculator helps you estimate the exact number of tiles needed based on the standard 450mm length.

Standard Ridge Specs

Tile Length450mm
BS 5534 StandardMechanical Fixing
Dry Kit Length3m / 6m Rolls

Dry Ridge vs Wet Bedding

Modern **Dry Ridge Kits** use a ventilated roll that sits under the tiles, allowing the roof to breathe while keeping out the rain. The tiles are then screwed into the ridge batten using stainless steel screws and plates.

**Wet Bedding** involves sitting the tiles on a bed of mortar. While aesthetically preferred for heritage and period properties, it is prone to cracking and requires maintenance every 10–15 years.

Mortar Ratios

For a ridge that lasts, use a 3:1 mix of sharp sand and Portland cement. Avoid using building sand alone, as it is too soft and will crumble under frost.

Cutting Ridge Tiles

At the ends of the ridge (the gables), you may need to cut a ridge tile to fit. Always use a diamond-blade disc cutter and wear appropriate PPE. Ensure the cut tile is at least half the length of a full tile for stability.

Pro Tip: Block Ends

At the gable ends, always use a 'Block End' ridge tile. This has a closed face that prevents birds and driving rain from entering the end of the ridge line.

Roof Ridge FAQ

Compliance Disclaimer

Working at height is dangerous. Ensure all roofing work is carried out using appropriate scaffolding and safety equipment. All installations must comply with local building control and BS 5534 standards.