Slate Tile Roof Pitch

The rise and the length.

Slate tile roof pitch.

The pitch of a roof is determined by 2 numbers. Roof pitch is a term used in the roofing industry to describe the angle slope of a roofing structure. 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. Slate tile requires a pitch of 4 12 or greater.

Higher exposure or different sized slates necessitated a greater roof pitch of 22 5 or more. Most commonly a roof pitch will be from 0 flat to 12 45. Additionally if the climate can cause backups of water as ice under the eaves the tile requires at least two layers of underlayment cemented together. 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.

Generally speaking 20 degrees is the lowest advisable pitch for a slate roof depending on the size of the slates and how much that the roof is exposed to moderate weather conditions. In areas with high winds the underlayment must be attached with corrosion resistant fasteners according to manufacturer s instructions. When slating with a shallow pitch a wide slate is highly recommended for maximum side lap or lateral lap side overlaps.