Classes are in session at college campuses throughout the United States. Every year, new students arrive with aspirations of becoming an asphalt doctor, asphalt lawyer or asphalt engineer. Some will choose the natural sciences like asphalt chemistry. Others may choose to study asphalt business or asphalt marketing. The psychology of asphalt technologists who write magazine articles , however, seems to be a potential growth area.
I know my wife would gladly offer a yearly scholarship to this field of study. Regardless of which field of study a student wishes to pursue in the broad area of asphalt, they have to start off with the basics. That being said, it seems an appropriate time to look at the basics of asphalt used in roofing applications, such as shingle manufacture.
What I remember from my school days was that we usually started a new course or textbook with a little history. Early people were generally limited to whatever roofing materials could be found naturally in their environment. In tropical areas, palm fronds were a practical and lightweight choice that remains popular even today.
The Plains Indians made their tipis out of the skins of animals like buffalo and the deer that they hunted. Mud and straw roofs were also frequently used in many areas of ancient Africa. Wood was also an option, but it was usually in conjunction with another material like mud or woven fibers that were placed over it to fill in the gaps.
Primitive houses like wattles and daub huts were frequently made in this way. China has a long history of advanced architectural techniques, and reportedly they had been using clay tiles as far back as 3, BC. Northern Europeans preferred locally available slate or wooden tiles, with wood being particularly popular for the roofs of Nordic churches. Slate is still dominant in Northern Europe and nearby countries like France. By AD thatch became common in Britain, but was also used in many equatorial countries, like Hawaii, Bali and Fiji.
Also used in Africa, in Kenya, thatch was made from sugar cane leaf. Thatching remained popular in the 18 th and 19 th centuries among the American pioneers as the materials were easy to find and install. They used thatching with a layer of sod underneath to insulate their rudimentary prairie houses, but these roofs risked frequent leaking and even collapse during a heavy rain.
Southern Europeans typically used baked clay for their roofs, resulting in the signature Terra-cotta look of Spanish and Mediterranean architecture.
By the early s concrete tiles painted red were being used as a lower cost alternative. The surface was covered with a protective layer of sand or ground shell. Nobody expected this invention to evolve into one of the most successful product developments in the building materials history. Right at the outset, this "composite" waterproofing material proved to be so reliable and affordable, it attracted the interest of major distributors and property developers.
Sears, Roebuck and Co. Henry M. Reynolds of Grand Rapids, Michigan, started hand cutting individual shingles in , making the manipulation and installation of the product easier and increasing its versatility and visual appeal. The Flintkote Company introduced crushed slate granules as the surfacing material. In , continuous roll die-cutting was brought into the manufacturing process. In the s, the performance of asphalt shingles was improved by the development of a diamond cut shape to increase resistance to wind uplift.
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