Minimum Angle For Slate Roof

Roof pitch refers to the measurement of the slope of a roof and you express this as a ratio.

Minimum angle for slate roof.

Table 1 minimum recommended laps in mm for different exposures and roof pitches moderate exposure index between 3m 2 s and 7m s slate size mm roof pitch length width 85 45 40 35 30 25 221 2 20 600 300 65 65 75 75 90 105 125 500 300 65 65 75 75 90 90 115 500 250 50 65 65 75 75 90 105 120 450 300 50 65 65 75 75 90 100 120. You consider some alternative solutions. This means for every 12 horizontal units the roof must rise a minimum of 4 vertical units. Also redland cambrian interlocking slate which is very realistic will go down to 15 degrees.

Generally speaking 20degrees is the lowest advisable pitch for a slate roof depending on the size of the slates and how much that the roof is exposed to moderate weather conditions. 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. When slating with a shallow pitch a wide slate is highly recommended for maximum side lap or lateral lap side overlaps.

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. A couple of likely slate suppliers are consulted and they confirm that they are happy to supply 600x300mm slates for a minimum roof pitch of 20 degrees assuming a minimum lap of 125mm. 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 shingles can only be installed on roof slopes of 4 12 or greater 33 slope.

With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 200 for slate roofs. 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. It is agreed that the roof pitch should be a minimum of 20 degrees preferably a bit more.