Minimum Degree For Slate Roof

Generally a slate roof is not installed on a pitch less than 4 12.

Minimum degree for slate roof.

The minimum recommended pitch for a natural slate roof is 20 degrees under sheltered or. The 30 degree 7 12 roof recommendation is backed up by testing according to the publication science daily. A 30 degree roof slope 7 12 pitch is the right pitch to aerodynamically handle high wind. 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.

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. 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. Higher exposure or different sized slates necessitated a greater roof pitch of 22 5 or more. Roof slope equivalents as rise.

Degrees to pitch rise in run table. The following table provides the minimum required. 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. Minimum required headlaps and offsets should not be compromised.

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. 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. 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. With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 200 for slate roofs.

The general recommendation for the minimum pitch for natural slate is 25. Lower slopes don t handle wind driven rain as well. The slope of a roof is often referred to as the roof s pitch. Roof slate is strong and resistant to acid and frost.

Steeper slopes increase the sail effect that makes them susceptible to wind. Considerations must be given to the extent to which water will migrate under the slate shingles. The result of your conversation is as follows. It lasts up to 400 years as a roofing material.

On the best functioning slate roofs the water flows down slope parallel with the length of the shingle to the next lower shingles.