Wood shingle

A section view of a type of wood shingle.

Wood shingles are thin, tapered pieces of wood primarily used to cover roofs and walls of buildings to protect them from the weather. Historically shingles were split from straight grained, knot free bolts of wood. Today shingles are mostly made by being cut which distinguishes them from shakes which are made by being split out of a bolt.

Wooden shingle roofs were prevalent in the North American colonies (for example in the Cape-Cod-style house), while in central and southern Europe at the same time, thatch, slate and tile were the prevalent roofing materials. In rural Scandinavia, wood shingle roofs were a common roofing material until the 1950s. Wood shingles are susceptible to fire and cost more than other types of shingle so they are not as common today as in the past.

Distinctive shingle patterns exist in various regions created by the size, shape, and application method. Special treatments such as swept valleys, combed ridges, decorative butt ends, and decorative patterns impart a special character to each building.

History of shingles

Historically, wooden shingles were usually thin (3⁄8 inch (9.5 mm) to 3⁄4 inch (19 mm)), relatively narrow (3 inches (7.6 cm) to 8 inches (20 cm)), of varying length (14 inches (36 cm) to 36 inches (91 cm)), and almost always planed or knifed smooth. The traditional method for making wooden shingles before the 19th century was to rive (hand split) them from straight grained, knot free, sections of logs pre-cut to the desired length known as bolts. These bolts were quartered or split into wedges. A mallet and froe (or axe) were used to split or rive out thin pieces of wood. The wood species varied according to available local woods, but only the more durable heartwood, or inner section, of the log was usually used. The softer sapwood generally was not used because it deteriorated quickly. Because hand-split shingles were somewhat irregular along the split surface, it was necessary to dress or plane the shingles on a shaving horse with a drawknife or draw-shave to make them fit evenly on the roof.[1] This reworking was necessary to provide a tight-fitting roof over typically open shingle lath or sheathing boards. Dressing, or smoothing of shingles, was almost universal, no matter what wood was used or in what part of the world the building was located, except in those cases where a temporary or very utilitarian roof was needed.

Shingle fabrication was revolutionized in the early 19th century by steam-powered saw mills. Shingle mills made possible the production of uniform shingles in mass quantities. The sawn shingle of uniform taper and smooth surface eliminated the need to hand dress. The supply of wooden shingles was therefore no longer limited by local factors. These changes coincided with (and in turn increased) the popularity of architectural styles such as Carpenter Gothic, Queen Anne, and Shingle style architecture that used shingles to great effect.

Hand-split shingles continued to be used in many places well after the introduction of machine sawn shingles. There were, of course, other popular roofing materials, and some regions rich in slate had fewer examples of wooden shingle roofs. Some western "boom" towns used sheet metal because it was light and easily shipped. Slate, terneplate, and clay tile were used on ornate buildings and in cities that limited the use of flammable wooden shingles. Wooden shingles, however, were never abandoned. Even in the 20th century, architectural styles such as the Colonial Revival and Tudor Revival used wooden shingles.

Types of shingles

Collage of different styles of wood shingles used in Chiloé architecture.

The simplest form of wood shingle is a rectangle about 16 inches (41 cm) long. The sides and butt of a shingle are often irregular; the sides may taper and the butt may not be square with the sides. Shingles that have been processed so that the butt is square to the sides are called rebutted and re-squared or rebutted and re-jointed shingles, often abbreviated R&R.

Shingles and shakes may be tapered, straight, split or sawn and any combination of these except straight-tapered. Different species and quality of wood are used as are different lengths and installation methods. Shakes and shingles may also be treated with wood preservatives and fire retardants before or after installation.

Shakes

A shake roof in Romania

A shake is a basic wooden shingle made from split logs. Shakes have traditionally been used for roofing and siding applications around the world. Higher-grade shakes are typically used for roofing purposes, while the lower grades are used for siding. In either situation, properly installed shakes provide long-lasting weather protection and a rustic aesthetic, though they require more maintenance than some other more modern weatherproofing systems.

The term shake is sometimes used as a colloquialism for all wood shingles, though shingles are sawn rather than split. In traditional usage, "shake" refers to the board to which the shingle is nailed, not the shingle. Split wooden shingles are referred to as shag shingles.

Modern shingles

Modern wooden shingles, both sawn and split, continue to be made, but they differ from the historic ones. Modern commercially available shakes are generally thicker than the historic handsplit counterpart and are usually left "undressed" with a rough, corrugated surface. The rough-surface shake is often considered to be more "rustic" and "historic", but in fact this is a modern fashion.

Some modern shingles are produced in pre-cut decorative patterns, sometimes called fancy-cut shingles, and are available pre-primed for later painting. The sides of rectangular shingles may be re-squared and re-butted, which means they have been reworked so the sides are parallel and the butt is square to the sides. These are more uniform and are installed more neatly as a result.

Shingles are less durable than shakes, particularly in wet climates; shakes are finished with a drawknife or similar tool which leaves a smooth surface that resists water penetration, and this in turn slows the softening of wood by microorganisms. Also, the method of splitting shakes rather than sawing ensures only straight-grained pieces (which are much stronger and less likely to warp).

Recycled rubber shake shingles

Modern recycling technologies have allowed the manufacture of rubber shake shingles, made mostly from old tires. These have the same look as a conventional wooden shingle but won't rot, curl, discolor, bend, crack, or take on moisture, and will also not allow moisture to escape, just like vinyl siding.

Shingle production

Wood selection

Wooden shakes in Poland

In North America shakes are typically made from California redwood (Sequoia sempervirens), Western Red Cedar (Thuja plicata), and Atlantic white cedar (Chamaecyparis thyoides), while in Scandinavia and Central Europe they are more commonly made from pine (Pinus sylvestris). There are various types of shakes, the main differentiating feature between shakes and other types of shingles is that shakes are split while most shingles are sawn on all sides. The sizes also vary from country to country; in North America shakes are usually made in 24-inch lengths - the most common, 18-inch barn shake, or even 48-inch shakes, which are typically used for siding. In Scandinavia shakes, traditionally used only for roofing, are generally smaller than in North America, measuring 13-16 inches long, 4-6 inches wide and 1/8 thick.[2] Likewise wooden shingles are manufactured in differing lengths, in North America, 16-inch, 18-inch and 24 inches.

Log handling and transportation

Logs are typically cut into appropriate lengths using a chainsaw, then the "ringers" or cuts are split with an axe into cubes which are small enough to handle, usually 100 to 450 pounds, then stacked on a rope. The rope is looped around the stacked wood and the ends passed through an eye spliced in the end. When the running end is pulled it tightens the "sling" rope around the blocks preventing them from falling out. The slings are then flown to a central location where they can be loaded on pallets for transport. Previously, swede saws, crosscut saws and hand saws may have been used to cut the logs, and a froe (a heavy blade 24 inches long and three inches wide with a handle at one end perpendicular to the blade) was used to split the ringers. This blade was driven into the wood using a mallet, then the wood could be pried apart by pulling on the handle if it would not split by driving the blade in alone.

On the left is a log that fell in 1920; in the foreground a ringer bucked from the log is being trimmed to remove waste; on the right is a finished sling of blocks.

Before helicopters came into common use for transporting the slings, they were sometimes processed in the bush and finished, hand-split, shakes were carried out in a pack frame. In steep areas, cables were strung along the slope to form a tight-line or tyrolean. Staples were driven into a block straddling the cable, and the block was slid down the cable to a landing accessible to a boat or truck.

Cutting

Both shakes and shingles must be edge grain cut, to prevent warping and splitting as the wood dries. When splitting blocks and manufacturing shakes or shingles particular care must be taken to consider the orientation of the grain in the wood. Likewise when bucking, care must be taken to ensure cuts are precisely perpendicular to the grain, to minimize waste and maintain product quality. When bucking, the log must be cleared off well, so the grain can be seen clearly, allowing straight cuts perpendicular to the grain. When splitting, the ringers are typically split from the bark to the heart, perpendicular to the grain. The heart wood is removed by splitting parallel to the grain, and the bark and sap-wood is removed, as well as any imperfections such as rot or bug holes. The initial split is always made on a knot, burl, check or other imperfection, to allow the blocks to be made as large as possible while disposing of any waste. The blocks should never be split where there is clear wood, or imperfections will be left in the block; or the block will have to be split too small in the process of removing flaws.

Canting a log

When cutting large logs or severely twisted pieces, it is often necessary to "cant", or split the entire log into "slabs". To split a log a ringer is removed at each end of the tree, exposing the interior. Wedges are driven into the face to split off a slab, usually on a natural check or imperfection which runs the entire length of the log. After the face begins to separate, wedges are driven into the resultant opening, starting very near the face and progressively working toward the other end of the log in small steps.

Slab split from log
Tiny Swedish shakes factory

Manufacture of shakes and shingles from block form

Advertisements from Canadian Forest Industries (1908)

Shake blocks are split into 1 inch thick slats called blanks, using either a hydraulic press with a blade attached, called a cuber, or split by hand using a froe and mallet. These blanks are uniform in thickness throughout if split from the same edge without flipping the block. Alternatively, the splitter may flip the block after a blank is taken off each edge, which results in a tapered split from end to end, called tapers or hand-split. The blanks which are not tapered require further processing before application to create this taper, and are run through a large band saw, pushed by hand to cut them from corner to corner forming a tapered shake, sawn on one face.

Shingles are cut from the blocks using a circular saw, typically 42-48 inches in diameter. The blocks are clamped in a carriage which slides back and forth across the blade, tilting and moving the block closer to the blade with each pass to automatically form a tapered cut of the correct thickness. The edges of the shingle are then cut with another circular saw called a "trim saw", to remove irregular edges. The result is a tapered shingle sawn on all six sides. The thickness of the butt, or thicker end of the tapered cut, is usually 3/8 inch thick, but is also commonly made to be 5/8 inch, and can be made to any custom specifications.

Chiloé, Chile

Nearly all the houses and buildings in colonial Chiloé Archipelago, Chile, were built with wood, and roof shingles were extensively employed in Chilota architecture. Roof shingles of Fitzroya came to be used as money called Real de Alerce.

See also

References

  1. ↑ Garvin, James L.. A building history of northern New England. Hanover: University Press of New England, 2001. Print. 29. ISBN 1584650990
  2. ↑ http://www.talotori.net/omaterpare.php Shakes and shingles (in Finnish only)
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