Slate Roof Pitch Change

Conclusions of the low pitch slate roof testing.

Slate roof pitch change.

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. A dramatic change in pitch will affect the way the roof looks the way water runs off of it and much more. 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. You consider some alternative solutions.

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. Download this free 2d cad block of a typical slate change of roof pitch detail including annotations and dimensions. Even a slight change in pitch can have a variety of consequences depending on the roof. Generally a slate roof is not installed on a pitch less than 4 12.

Following the successful test results we are happy to advise specifiers and contractors that they can choose a siga natural slate roof as low as 15 degrees sheltered or moderate exposure and 17 5 degrees severe exposure if the slates are hook fixed with a 150mm lap. It is agreed that the roof pitch should be a minimum of 20 degrees preferably a bit more. The slope of a roof is often referred to as the roof s pitch.