One of the many advantages of using cedar shingles is that they can be used on roof pitches as low as 14 degrees.
While a low pitch roof may not show the aesthetic qualities of cedar shingles to full advantage they provide a light-weight, durable solution where a pitched roof is required.
To achieve a sound, watertight roof the gauge of the shingle (assuming the standard 5X or 400mm shingle) must be closed to 95mm giving a ‘4-ply’ roof.
A water impermeable, vapour permeable underlay that meets the requirements of Annex A of BS 5534:2003+A1:2010 is also required. This underlay acts as a second line of defence in extreme circumstances. Ideally the underlay laps should be sealed using double sided tape. Nail tape should be used over the rafters and at any other points of batten fixing. This acts as a seal around the nail.
As with all roofs the detailing around valleys, abutments and items such as roof windows is important to protect the waterproof integrity of the roof.