Minimum Gradient For Slate Roof

The slope of a roof is often referred to as the roof s pitch.

Minimum gradient for slate roof.

Minimum roof pitch for shingles. Run in degrees and as percentage the minimum roof slope allowed by code for any type of roof is in 12 applicable only to coal tar pitch roof systems. The following table provides the minimum required. The general recommendation for the minimum pitch for natural slate is 25.

Roof slope equivalents as rise. 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. Express the slope of a metal roof by a ratio which indicates the pitch of the roof. Higher exposure or different sized slates necessitated a greater roof pitch of 22 5 or more.

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. 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. With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 20 0 for slate roofs. The profile is the shape taken by the sheets when you bend them to form panels.

The minimum slope of a roof depends on the roof s profile. Wood shingles minimum roof slope roof pitch r905 7 2. This means for every 12 horizontal units the roof must rise a minimum of 4 vertical units. Slate shingles can only be installed on roof slopes of 4 12 or greater 33 slope.

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. Generally the steeper the roof the better with regard to service life of slate. Slate shingles minimum roof slope roof pitch r905 6 2. 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.

But since there is still a wide variety of slate roofing systems there are occasions when the minimum pitch can go down to as low as 15 0 depending on the uniqueness of the roof. Not only will slate shingles last longer on these steeper slopes but they will be more visible from grade and show off their natural beauty.