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.
Minimum pitch for slate roof tiles.
The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.
They last from 60 to 200 years with their main problems lying in the fastening material which can rust if made from corrosive substances.
Slate tile requires a pitch of 4 12 or greater.
The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.
Metal roof shingles require a minimum roof pitch of 3 12 or greater.
Clay and concrete tile requires a minimum roof pitch of 2 1 2 12 or greater.
All tiles and slates have a minimum roof pitch which is set out in order to protect the roof from water penetration.
Mineral surfaced roll roofing requires a minimum roof pitch of 1 12 or greater.
Steps to specifying a low pitch slate roof.
Although bs 5534 recommends a minimum pitch of 20 ssq has developed a successful slate roofing system that allows the roof s pitch to be reduced to 17 5 generally and under some circumstances as low as 15 in areas considered to be unexposed.
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.
Confirm the exposure level of the site using our annual driving rain index map.
If you do have a long rafter length extreme local topography or you are working on a tall building we.
The minimum pitch for each product can be found in the table below and in the product brochure or within the products pages some tiles and slates incorporate design features allowing them to be laid at a low minimum pitch.
Slate tiles whether natural or synthetic are expensive but they can add value to a home because of their appearance.
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.