A look into clay tile history
It is said that the first historically known clay roofing tiles have been used in Neolithic China as early as 10.000 B.C.!
5000 years ago, clay roofing tiles have been used in Babylon.
From there they made their way via Egypt and Greece to Rome. Rome was called the city of tiled roofs. The Romans introduced Middle Europe to their excellent characteristics and long lasting durability. Even today, buildings that have been “tiled” by the Romans exist.
In the 8th century, the Hiersar Monastery in Calw and later the monastery in Lorch, Southern Germany.
Clay roof tiles characteristic as “fire proof roofing” were recognized 1212 AD by King John of England as he issued building by-laws for London to eliminate combustible roof coverings. The devastating fires from 1679 in Boston prompted the establishment of building and fire codes in New York and Boston.
By the 18th century, tiled roofs had become the standard in Europe, wherever there was an abundant local supply of suitable raw materials. Back then, the “craft” of tile making was hard labor and required excellent knowledge of the materials and processes involved. Tile burning was done in piles, in which clay tiles and burning material, like coal or wood, was layered into stacks and covered by earth.
The first attempts in industrial production of clay roofing tiles were started in the 19th century. Improvements to the transportation infra structure and the availability of steam engines helped.
Advances in material knowledge and the introduction of the so called “ring kiln” by Hoffman in 1858 allow the further advance of the quality. With this kiln, continues burning was achieved. It allowed the gradually rising of the temperature and was fired by coal, thrown in from above.
New forms of clay roofing tiles were introduced and the development took a leap forward to the design and characteristics we know today. Interlocking, strong and durable clay roofing tiles with consistent quality are available to be used as long lasting roofing material. As the popularity of clay roofing tiles grew, transport and production were expanded.
Due to the increase in demand the method of delivery was changed. The use of clay roofing tile used to be limited to areas were horse drawn wagons could deliver them. This limited their distribution. This all changed with the introduction of motor vehicles.
Further easing of the work load was achieved with the introduction of early loading and crating systems.
In the early 1960s the mining of the raw clay was switched over to machinery. This was in part to the rise in demand for clay roofing tiles.
Europe has a long lasting clay roof tile history, that is highly visible if one looks at the roofs of major European cities. Now in the 21st century, the quality and durability of building materials is becoming increasingly important for the value minded home owner that can appreciate the superiority of clay roofing products.
The first Composite Shingle
The first composite roofing was used in New England in the 1840s. These roofs were usually made of a felted or woven fabric that was covered with a tar-like substance like pine tar and sand. Later improvements included saturating the fabric with asphalt and a mixture of materials like talc, sand, or powdered gravel or limestone. The first true composition roofing was credited to the S.M and C.M Warren Company.
This roofing was made of coal tar, which was a byproduct of the gas lighting industry, and rolled felt that was saturated with the tar and fine gravel. Roll roofing emerged in the last part of the nineteenth century and became commonplace at the beginning of the twentieth century. Roll roofing was soon replaced by asphalt shingles.
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 by 16 inch 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.
Asphalt shingles were initially cut into 8 by 12 ½ inch pieces that were meant to imitate the wood shingles. Originally, the surfacing materials were natural materials like black or green slate. Several varieties of patterns were produced and attachment systems were introduced. Shingle sizes eventually became more varied.
The greatest innovation in the asphalt shingle industry was the introduction of the multitab strip shingle. Bird and Son introduced the Neposet twin, which was a 12 ½ by 20 inch shingle with a slot tab that divided the piece to look like two shingles. Larger pieces made the price of installation decrease while the tab pieces imitated wood shingles.
Prepared Roofing Manufacturers Association was later formed as a means to promote asphalt products as well as improve material quality. Also, asphalt shingles had a higher flame-resistance rating than wood shingles and were promoted by the manufacturers because of this fact. Pattern and size variety reached its highest point in the 1920s.
Shingles could be diamonds, appear thatched, or even have scalloped edges. The use of different felt sizes and granule coatings helped to create a shadowed effect. The variations of tabs and interlocking shingles made it easy to install pieces in a straight line and protect against the pieces being lifted by strong winds.
By the early 1930s, experimentation in sizes and shaped seemed to dwindle due to the upcoming Great Depression. Manufacturers had to cut their production and the building industry saw a dramatic decrease. Soon, a standard in shingle size was developed as being 12 by 36 inches, which was a multitab shingle and is still the industry standard today.
Though there was a dramatic decrease in size and shape variety, the amount of available colors seemed to grow exponentially. Colors were originally slate colored, which evolved to a variety of colors and blends. Decorative effects were available made from a wide variety of colors. Special rollers made it possible to put a texture on the top surface.
The Ruberoid Company was the first manufacturer to offer asphalt shingles with a rolled wood-grain texture. At the end of the 1950s, 12-by-36 inch, multitab, blue shingles were the most popular roofing material.
In the 1970s, a glass fiber-reinforced felt was introduced. This material had increased tensile strength and was thinner and more light-weight. Several layers of these felts were laminated together to give a dramatic shading effect.
Felt, which is the primary ingredient in asphalt roofing, was made originally of wool rags, cotton, or paper. Wood fibers later became the main ingredient. Felt is produced in a roll and then saturated with asphalt flux. Asphalt flux is a distilled crude oil. The saturated felt is then passed through a pan where the coating is applied.
The coatings may have included mineral fillers like slate flour or powdered oyster shell. These materials helped to stabilize the mixture. The sheet was then passed under a shower of mineral or ceramic granules. Water was sprayed to cool the material, which was then rolled with a pattern to imprint either texture or patterns. The material was the cut with a rotary knife and possibly dusted with talc to keep the pieces from sticking to each other. Color could be created by adding fillers and granules in the desired colors.
Colors varied depending on the fashion or regional preference as well as the available technology. Ceramic-fired granules were introduced around 1930 and produced colors of natural stones. Asbestos was added to some shingles to increase fire resistance.
Uses and Installation
Asphalt shingles were used in replacement of wood shingles due to affordability. The asphalt and fiberglass shingles dominated the residential roofing market since their introduction. Shingles should be installed in an overlapping method to help move water downward. Shingles have several small pieces and joints but depend on the overlapping installation to keep water from penetrating these spots.
The amount of shingle exposed varied on every row. It was suggested that two layers of felt be used on low-sloped roofs. Shingles could also be fastened in a variety of ways. Originally, most shingles were nailed to the roof with the use of a tern-plate disk. The disks were made of a thick felt or cork. Large-headed galvanized roofing nails soon dominated the market as a method of fastening shingles. Spot cement could be applied after the shingles had been fastened, usually using a putty knife or caulking gun.
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.
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.
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.
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.
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.
—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.
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.