Wood Shingle

A wood shingle is a thin, tapered piece of wood used in overlapping rows to shed water from a roof or wall. In current North American usage, a shingle is sawn smooth on both faces and is thinner and more regular than a shake, which is split from the log on at least one face. Historically the two words were used more loosely, and in colloquial speech "shake" is still often applied to any wood roof unit.

Species

Durable, straight-grained, decay-resistant woods are preferred, and traditionally only the heartwood was used, because sapwood rots quickly. In North America the main roofing species are western red cedar, with Alaskan yellow cedar, California redwood and Atlantic white cedar also used. In Scandinavia and central Europe, Scots pine and local spruce are more common, and in Latvia aspen is the most popular shingle wood. Oak shingles are recorded in the history of ancient Gaul and Iberia. In Japan, very thin split shingles fastened with bamboo nails roof temples such as Kinkaku-ji and Ginkaku-ji in Kyoto; Korean shingle-roofed houses are called neowa-jip.

Sizes

North American sawn shingles are made in 16, 18 and 24 in (406, 457 and 610 mm) lengths; under the Cedar Shake & Shingle Bureau's grading rules these are known as Fivex, Perfection and Royal respectively. Butts are usually about 3/8 in (10 mm) thick. European shingles vary widely: Scandinavian shingles may be only 13-16 in (33-41 cm) long and about 1/8 in (3 mm) thick, while Polish and Slovak shingles can be around 36 in (91 cm) long and over 1 in (25 mm) thick.

History

Before the 19th century, shingles were split by hand from straight, knot-free blocks with a froe and mallet, then smoothed with a drawknife. Steam-powered sawmills in the early 19th century made uniform sawn shingles cheap and plentiful, and wood shingles remained common in North America into the 20th century, including on Colonial Revival and Tudor Revival houses. In many cities, fire risk led authorities to restrict wood roofs in favour of slate, tile or metal.

Performance

Shingles are thinner than shakes and generally less durable, especially in wet climates. They need good ventilation underneath so they can dry after rain; many installers lay them on spaced battens or a ventilating mat. Wood shingles can be treated with preservatives and fire retardants before or after installation; untreated wood roofs are restricted in many wildfire-prone areas. Wood shake is among the coverings typically used at pitches of about 3:12 (14°) or steeper.

Weathering

Untreated cedar weathers from reddish-brown to silver-grey within a few years. Moss, lichen and debris that hold moisture shorten life, so regular cleaning is part of normal maintenance.