Composite roofing, better known as asphalt shingles, is the most common choice of homeowners when doing roofing project. It is fairly inexpensive, durable, comes in many different colors, and numerous designs. Asphalt shingles are very easy to install, and require little maintenance. Asphalt shingles come in two basic types: fiber glass and organic.
Organic shingles consist of an organic felt material which is generally paper saturated with asphalt to make it waterproof. A top coating of adhesive asphalt is then applied and the ceramic granules are then embedded. Organic shingles contain around 40% more asphalt per square (100 sq. ft.) than their fiber glass counterpart which makes them weigh more and gives them excellent durability and blow-off resistance.
Fiber glass shingles have a glass fiber reinforcing mat manufactured to the shape of the shingle. This mat is then coated with asphalt which contains mineral fillers. The glass fiber mat is not waterproof by itself. It's purpose is for reinforcement. What makes the fiber glass shingle waterproof is the asphalt. However, the asphalt itself will not stick to the mat. For this reason, "fillers" are used. The fillers in the asphalt cling to the glass fibers in the mat. The asphalt then encapsulates the glass fibers, fills all of the little holes and voids in the mat rendering it waterproof. After this cools a bit, an adhesive asphalt is used to cover the mat and the ceramic granules are then embedded.
The ceramic granules are there for two reasons. The primary reason is to protect the shingles from the sun. The sun's UV rays are very damaging to asphalt and cause it to deteriorate prematurely. The second and more obvious reason for the granules is aesthetics. Asphalt shingles are available in a wide variety of colors to match almost any home or landscape.
So which type is better? By far, the more popular shingles are the fiber glass ones. This may be attributed to the fact that they are cheaper and easier to manufacturer than organic shingles making them more cost effective to the homeowner, it may be that they are easier to work with, or they may simply be a personal preference of the roofing contractor.