Slate Roof Pitch Angle

Conclusions of the low pitch slate roof testing.

Slate roof pitch angle.

Unlike most other roofing materials and even slate from other quarries where sizes larger than 50 25 cannot be achieved ssq slate allows you to design roofs as low as 17 5 in pitch. 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. The slope of a roof is often referred to as the roof s pitch. 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.

In the roofing trade the go to term is pitch and it is expressed in terms of 12 inches so the pitch of a roof is determined by how many inches the slope rises for every 12 inches it runs horizontally. Roof pitch the angle of a roof not only determines what slates to use but the amount of overlap that the slate roof needs to remain waterproof. 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. The roof pitch calculator is a convenient online tool you can use to quickly assess the pitch of your roof to determine the length of rafters you need.

Roof pitch or slope is a measure of vertical rise to horizontal run expressed in inches per foot. Roof pitch is used to describe the slope or angle 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. Generally a slate roof is not installed on a pitch less than 4 12.

With regards to the pitch the building standard code bs 5534 recommends a minimum pitch of 20 0 for slate roofs. Pitch angle incline slope they all can be used to refer to the steepness of a roof. The roof pitch is important in determining the appropriate installation method and how much roofing material will be needed. Slating terms and phrases if you are not a seasoned roofer some of the terms used for slates batten spacing or overlapping of the slates can add to the confusion.