The Sparrow of Shingles: Asphalt
Asphalt shingles are ubiquitous. Although cold hard statistics are unavailable, roofers agree that Asphalt shingles are the most commonly used material for roof covering. This is probably because asphalt shingles are easy to come by, affordable, and simple to install.
History of Asphalt Shingles
The genesis of Asphalt shingles can be traced back to the widespread practice of Asphalt roll roofing. This is essentially un-rolling a carpet like asphalt roll over the surface of a roof. Asphalt roll roofing is actually still used today in some commercial buildings where the roof cannot be seen. The use of Asphalt slates for shingling became popular in the early 1900’s, when it was discovered that adding granules to the composition of the shingle drastically increased the durability of the shingle. The low cost, accessibility, and ease at which asphalt shingles could be installed lead to an explosion of asphalt shingle installations throughout the United States.
Composition of Asphalt Shingles
All shingles were originally organic, utilizing felt for its composition, which is essentially cotton rag. But in the 1920’s, cotton rag became more expensive and alternative materials were used: wool, jute, manila and wood pulp. As time rolled on, fiberglass was added to the composition of asphalt in order to increase wind and rain resistance. Asphalt shingles split into two categories: organic and fiberglass. The former is a base mat made with materials like paper, cellulose, and wood fiber. Said materials are saturated with asphalt to make them waterproof, and then a top coating of an adhesive is applied to hold the material together. Organic shingles are prone to fire damage, and are therefore utilized less frequently. Fiberglass asphalt shingles are comprised of a base layer of glass fiber, bonded with resin to produce a mat. This mat is then coated with asphalt, packaged, shipped to roofers, and then layered upon the roofs of American homes.