Cedar shingles are narrow slices of wood which are sawn from a cedar log and squared off to standard sizes, usually 16 inches (40.6 cm), 18 inches (45.7 cm), or 24 inches (60.96 cm) square. It is also possible to get cedar shingles in different shapes, which are used to make patterns on the side of the building. The thickness of cedar shingles varies from 5/8 inch (1.59 cm) to 1-1/2 inches (3.8 cm). Both sides, sometimes called faces, of cedar shingles are sawn. These shingles are used to cover roofs and walls of buildings.
Both red cedar and white cedar are used to make cedar shingles. Red cedar tends to be more resistant to decay than white cedar, but it ages to a darker color. These are very durable types of wood, which means that a roof or wall covered with cedar shingles will have a long service life. Most manufacturers and installers will guarantee a 20- or 25-year life span. Many variables have an impact on the life span of a roof, including exposure, the presence of overhanging trees, maintenance, climate, moisture, and proximity to salt water. In general, cedar shingles last from 30 to 40 years. Shingles impregnated with fire retardants and/or preservatives have a longer life span.
The color of cedar shingles changes over time, usually to a pleasant silvery gray. Occasionally, stains appear on the surface of the shingles. These stains may be extractive bleeding stains, which are caused by tannins in the wood being drawn to the surface. This is more likely to happen in moist conditions. Cleaners with oxalic acid are usually the best choice to remove extractive bleeding stains.
In some areas, cedar shingles are prohibited by local ordinances because they are believed to be a fire hazard. Today, cedar shingles can be pressure impregnated with a fire retardant that makes them as resistant to fire as any other roofing material. These treatments are rigorously tested on both new shingles and shingles as old as ten years. Four kinds of flame movement tests are performed to be sure the fire retardant treatment meets fire protection standards. If local building codes have not been updated, it may be possible to get a variance.