In areas with high winds the underlayment must be attached with corrosion resistant fasteners according to manufacturer s instructions.
Slate tile roof pitch.
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.
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.
For tile shingle slate and metal roofing.
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 rise and the length.
Roof pitch is a term used in the roofing industry to describe the angle slope of a roofing structure.
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.
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.
When slating with a shallow pitch a wide slate is highly recommended for maximum side lap or lateral lap side overlaps.