What is the minimum pitch for a slate roof?

The roof is an essential component of any building, serving as the first line of defense against environmental hazards. Over the years, roofs have undergone significant changes, with pitched roofs often associated with a more classical appearance. However, they remain the most common and efficient solution to ensure maximum protection.

When considering the minimum pitch for a slated roof it is necessary to establish the exposure of the site, the length of rafter and the height of the building.

The recommendations shown above are based on a maximum height to eave of 12m and a maximum rafter length of 9m in moderate exposure and 6m in severe exposure.

The NHBC standard (the UK’s leading provider of warranty and insurance for new-built homes) indicates that the minimum pitch for a slate roof is 20 degrees subject to headlap (Section 7.2.19: Table 12).

The British Standard BS 5534:2014+A2:2018 (Slating and tiling for pitched roofs and vertical cladding. Code of practice) also indicates that the minimum roof pitch for natural slate is 20 degrees in the case of a project situated in an area with moderate exposure and with a slate 500mm long and a 115mm overlap. For more information see the tables above.