Slate Roof Pitch Regulations

Traditionally a minimum roof pitch of 20 was recommended in bs 5534 but modern tiles and slates have now been designed for applications as low as 15.

Slate roof pitch regulations.

A couple of likely slate suppliers are consulted and they confirm that they are happy to supply 600x300mm slates for a minimum roof pitch of 20 degrees assuming a minimum lap of 125mm. The roof pitch should be at least 20 which is influenced by the length head lap and thickness of the slate. It is uncommon to find a roof below 15 but for those very low pitch applications there are interlocking clay pantiles available suitable for use down to 12 5. The headlap of the slate is adjusted according to the roof pitch.

Headlap as defined in the national slate association s slate roofs design and installation manual 2010 edition is the length in inches of the upper portion of a roofing slate that is covered by the butt of the slate two course above. In order to provide you with the opportunity to specify low pitched slate roofs below 20 with confidence siga commissioned the bre to carry out a set of tests. Clay and concrete roof tiles can only be installed on roof slopes of 2 1 2 12 or greater. This means for every 12 horizontal units the roof must rise a minimum of two and one half vertical units.

Minimum roof slope roof pitch r905 3 2. You consider some alternative solutions. Minimum fixing on double lap slates. Conventional low pitch slate roofs are recommended down to a minimum of 20 in areas of sheltered or moderate exposure providing a 500x300mm slate is used and a headlap of 115mm.