Definition of Asphalt Shingles
In the United States, fiberglass-based asphalt shingles are by far the most common roofing material used for residential roofing applications. They are easy to install, relatively affordable, last 20 to 50 years and are recyclable in some areas. Asphalt shingles come in a large number of styles and colors.
The protective nature of paper and fiberglass asphalt shingles primarily comes from the long-chain petroleum hydrocarbons, while wood shingles are protected by natural oils in the cellulose structure. Over time in the hot sun, these oils soften and when rain falls the oils are gradually washed out of the shingles. During rain, more water is channeled along eaves and complex roof lines, and these are subsequently more prone to erosion than other areas.
Eventually the loss of the oils causes asphalt shingle fibers to shrink and wood shingles to rot, exposing the nail heads under the shingles. Once the nail heads are exposed, water running down the roof can seep into the building around the nail shank, resulting in rotting of underlying roof building materials and causing moisture damage to ceilings and paint inside.