Minimum Slope For Slate Roof

As per the nrca roofing and waterproofing manual fifth edition they recommend that roof deck slopes intended for the application of steep slope materials at 4 12 18 degrees or greater page 405.

Minimum slope for slate roof.

The short simple answer is 2 12 has traditionally been considered the absolute minimum acceptable roof slope suitable for asphalt shingles. 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. 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. You need to consider the slope requirements of each panel to determine this minimum slope.

Minimum roof pitch is the lowest angle at which a roof can be designed so the roof covering remains watertight. Mineral surfaced roll roofing requires a minimum roof pitch of 1 12 or greater. Built up roofs require a minimum roof pitch of 1 4 12 or greater. The minimum slope of a roof depends on the roof s profile.

What does minimum roof pitch mean. There are some manufacturers that can go slightly lower such as the siga 56m natural slate which can go down to 20 in some instances if used with slate hook systems. The general recommendation for the minimum pitch for natural slate is 25. 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.

Wood shakes require a minimum roof pitch of 3 12 or greater. 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. Slate and slate type shingles require a minimum roof pitch of 4 12 or greater. The minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems.

Express the slope of a metal roof by a ratio which indicates the pitch of the roof. The profile is the shape taken by the sheets when you bend them to form panels. Generally a slate roof is not installed on a pitch less than 4 12. The following table provides the minimum required allowable roof slope for each type of roofing material mentioned in the code.

The slope of a roof is often referred to as the roof s pitch. Wood shingles require a minimum roof pitch of 3 12 or greater. Higher exposure or different sized slates necessitated a greater roof pitch of 22 5 or more. These factors include the pitch of the roof the type of slate being used the size of the lap the size of the slate as well as the site s exposure rating.