Minimum Roof Pitch by Material (UK, BS 5534)

Roof coveringMinimum pitchUS equivalentStandard
Plain clay tiles35°8.40/12BS 5534
Concrete interlocking tiles17.5°3.78/12BS 5534
Large format interlocking tiles15°3.22/12BS 5534
Natural slate20°4.37/12BS 5534
Fibre cement slate20°4.37/12BS 5534
Standing seam metal5°1.05/12Manufacturer
Single-ply membrane1°0.21/12BS 6229