Minimum Pitch For Slate Roof Ireland

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.

Minimum pitch for slate roof ireland.

A greater pitch is likely to make the house look top heavy. The min pitch for slating was changed from 22 5 to 25 in 2002. Higher exposure or different sized slates necessitated a greater roof pitch of 22 5 or more. Minimum pitch for slate roof 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.

This came about due to the revisions in the code of practice icp2. 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. Typically roof pitches in ireland are in the 30 to 40 degree range to repel the rain quickly from a slate or tile covering and provide some degree of practical attic space for storage. 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.

2002 irish code of practice for slating and tiling. In general terms the minimum pitch is 22 5 degrees but we have seen pitched roofs perform down to 15 degrees pitch. In the past slates were thought to be effective at 22 5 degrees and this was set as the minimum acceptable pitch. The roof finish manufacturer will specify the minimum and maximum pitch required to ensure weatherproofing.

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. Relating to the pitch the building standard code bs 5534 recommends a minimum pitch of 20 deg for slate roofs which can be achieved through specific design although most manufacturers recommend a 25 degree minimum pitch. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code. The answer depends on a number of factors such as height rafter length site location slate or tile being used etc.