Amazing Asphalt

How 1920s Shingle Types and Designs Created the Golden Age of Composition Roofing

By GORDON BOCK

At the turn of the 20th century, when man-made building materials really began to take hold, manufacturers combined production innovations and marketing flair to produce a new kind of roofing generally called composition shingles: fibers of some sort saturated or mixed with a binder. Taking off in the building boom of the 1920s, these asphalt shingles were highly popular, not only for their ease of installation, and resistance to fire, but also for their astounding variety of novel shapes and colors-creativity that might cinch the sale of a house in a highly competitive market. Since many of these shingles styles are in limited production today (if made at all), understanding the basic asphalt shingles available in our grandparents' era is the place to begin for anyone who faces a composition shingle restoration project.

Humble Origins
Before we look at the birth of the asphalt shingle, let's step back to the 19th century to get a handle, if you will, on the pre-history of the composition roof. In the 1840s there was a ripe market for new roofing materials to build the growing towns of the Midwest and West Coast. Corrugated iron was the most promising innovation, however a few experimenters were taking another route by saturating layers of felt, paper, or flax with fish oil or pine tar, then covering this concoction with sand or ground shells. Samuel and Cyrus Warren of Cincinnati were two of these pioneers who revolutionized this process in 1847.

They found that coal tar-a waste product of the gas lighting industry-made an ideal adhesive for what we now call built-up roofs. Not to be overlooked was the fact that the gas companies would actually pay to have the stuff taken away. The brothers soon had a thriving business manufacturing and installing their roofing in Chicago, St. Louis, and Philadelphia. Other leaders in the industry were Samuel Barrett of Chicago and Michael Ehret of Philadelphia. In 1868, Ehret patented the slag (or cinder) roofing system, which used this material as a top coating.

Coal tar was a big boon to composition roofing, but as the gas companies found it had other uses in the nascent chemical industry, they started charging for it. Naturally occurring asphalt, the obvious alternative, had been tried for waterproofing roofs in the early 19th century, and by the 1880s large quantities were being imported from the Pitch Lake in Trinidad. However, it took the first oil well in Pennsylvania in 1859, and the subsequent growth of the petroleum industry, to make asphalt plentiful enough.

By 1889, composition roofing was a well-established contracting business. After 1900, one could buy essentially the same roofing coated with granulated stone from suppliers as common as Sears, Roebuck and Co.-the ubiquitous roll roofing that protects barns, garages, and industrial buildings.

 Shingles Reborn
The idea of shaping asphalt roofing into individual shingles is credited to Henry M. Reynolds of Grand Rapids, Michigan in 1903. A roofing contractor and manufacturer, he started cutting stone-surfaced roofing into 8 x 16 shingles-by hand, with a knife. Adding crushed granules of slate-a 1914 idea from F.C. Overby of the Flintkote Company-helped weight such shingles down to the roof. From here a new industry seems to have sprung. A big help was a push by the National Board of Fire Underwriters to eliminate wood shingle roofs, starting around 1911. World War I was a boost too because asphalt shingles made use of non-strategic materials. It was not until about 1915, however, that manufacturers perfected the machinery for roller-die cutting thick roofing into irregular shapes on a continuous production line, thereby opening a cornucopia of asphalt shingle products to the market.

 INDIVIDUAL SHINGLES By the late 1920s, the bulk of asphalt shingles on the market were not strip types, as they are now, but individual shingles (a regional specialty at best for most of today's manufacturers). Individual shingles were not only the most logical product to make when processing large rolls into smaller forms, they were economical and easy to install. Many types of individual asphalt shingles found a ready market for over-roofing existing roofs, such as wood shingles.

 Giant Shingles-Individual rectangular shingles as large as 12 by 16 were often distinguished from standard or unit shingles, though each manufacturer had their own distinctions and terminology-Jumbo or Massive, for example. Produced in a variety of shapes-some designed to speed installation-and colors, such as brown, Spanish red, maroon, green, grey, black, and purple, they could be selected for a monochrome roof or combined for a blended effect. Giant shingles were installed in either the American method (where shingles overlap conventionally at their bottoms), or the Dutch lap method (where shingles lap to one side). At least one manufacturer offered them in mixed lengths that created the random exposures evocative of shake or thatch roofs.

 French Method Shingles-Asphalt shingles cut in a diamond or hex pattern, reminiscent of the chateau roofs of the Loire Valley, were often called French Method shingles and very popular. These shingles came in two common sizes-12 x 12 and 16 x 16 -often incorporating tabs or clips at the bottom corner to guard against wind lift. Colors tended to be stone tones of red, blue-black, green, and grey. A few companies tried coloring slate and gravel by 1919, but success was limited and the natural stone proved most durable. Because they only overlapped at shingle perimeters, asphalt French Method shingles provided just a single-coverage roof-that is, only one layer of roof material. This single thickness of asphalt was not always acceptable for new construction, but worked fine for over-roofing. Not content to clone a continental pattern, many manufacturers came up with their own spin on the French Method pattern by clipping the corners into a hex, or deforming the diamond slightly.

 Interlocking Shingles
-Practical as they were, the large, exposed edges of individual shingles made of a flexible asphalt-and-felt base made them prone to wind-lift and subsequent breakage in storms or areas of the country with windy climates. Finding inspiration in a potential problem, manufacturers surmounted the wind-lift issue by conniving patterns to completely interlock the shingles.With tabs and ears that slid into slots created in the previous course, interlocking shingles were mechanically similar to a self-sealing cereal box top. The industry evolved two general designs: long, uncut tabs (sometimes called T-lock, after the appearance of the shingle) and short, slitted ears. Besides creating an integral roof with decorative course lines much like a basket or quilt, interlocking shingles had the advantage of double coverage.Though evidence of interlocking shingles is murky in the early 1920s, by 1929 these products are common in building product ads. They remain practical and popular to this day in high-wind prone regions of the country. Surprisingly, they also seem to have been well adapted to covering the rolled eaves used to evoke thatched roofs on many cottage-style houses of the 1930s and '40s.

  NOVELTY STRIPS Moving beyond true individual shingles, there once was also a whole class of strip shingles that came close to individual shingles in effect. Like decorative ceramic floor tile or paving bricks, their irregular, but mundane-looking, tabs belied clever patterns produced once the shingles overlapped on the roof.

 Most popular were hex shapes, especially in two-tab strips. Appropriate for both new construction and reroofing, these strips were common in two sizes: Standard and Giant-the latter with a 13 1/2 tab.  Modified octagons in four strips were also marketed. Besides the interesting roof pattern, octagons could create a fiesta look by laying alternate strips in different colors. Octagonal strips were also appealing due to their small butts, which worked well around dormers and other angled areas.

 The novelty strip concept could even be stretched to include Arabesque patterns, such as the Nelson Master Slab and Continental Artstrip, particularly popular after 1930. Ceramic granules, perfected in the 1930s, increased the color possibilities. By piling multiple colors of mineral on a single strip, manufacturers could produce a tapestry effect, more variegated than any natural roofing material could ever be.

As the 1940s dawned, there were even broad shadow strip shingles on the market, manufactured with early versions of the rhombus-shaped dragons' tooth tab so ubiquitous today for textured architectural asphalt roofing products.

Some shingles were even developed with specific house styles in mind. Whatever their purpose, their contribution to the architecture and historic character of a building is no less significant than the siding design or paint color. Though many of these products fell out of favor through the 1950s and 1960s, their delightful variety is starting to bring eye-appeal back again to asphalt roof shingles of the 21st century.

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