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 lightweight, 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.
