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The Anatomy of a Shingle


By Alex Pecora on February 14th, 2022

We use the finest raw materials in our asphalt shingles to make them durable. At the core of our asphalt roofing shingles are three basic components: a tough fiberglass base mat, waterproofing asphalt, and high-performing surface granules.

To make shingles, fiberglass mat is fed into a fabrication line. The material passes through a saturator tank filled with hot asphalt, which coats the fibers. Various colors of ceramic coated mineral granules are used as a topcoat on the shingles to protect them from the sun’s ultraviolet rays, and to add an attractive finish.

The back surface of the shingles is then coated with sand or slag fines to keep the shingles from sticking together during storage.

What is a shingle fiberglass mat?

Fiberglass mat is produced from very fine glass fibers and a binder that holds them together. It is the structural base of the shingle that carries the shingle through the manufacturing process and provides the majority of reinforcement properties needed for good performance and long life.

What is the role of asphalt in a shingle?

Asphalt’s primary purpose in shingles is to serve as a waterproofing agent. Asphalt also holds the granules in place and adds to the overall strength of the shingle.


Asphalt and fiberglass mat are made into long rolls that are later coated with granules and cut into individual shingles.

What are shingle granules?

Granules are fine grain, opaque, crushed rock particles that are pressed into the surface of the asphalt. They block ultraviolet (UV) light from reaching the asphalt in the shingle.

UV rays, if allowed to reach unprotected asphalt, will age the asphalt prematurely. The best granules are colored by a ceramic coating and do not allow light to pass through them.


Roofing granules come in different hues that are combined to create a shingle’s color blend.

What is shingle backsurfacing?

Shingle backsurfacing is usually a fine mineral material, such as sand or slag fines, applied to the back of the shingle. It’s purpose is to prevent asphalt shingles from sticking to each other in storage.

What are asphalt sealant strips?

Asphalt self-sealing strips are continuous or intermittent lines of asphalt designed to bond the shingles together to resist wind uplift. Our CertaSeal™ shingle adhesive technology can protect shingles from winds up to 130 MPH*.

Quality assurance & independent testing

Our shingles are made with a strip of clear polyester film on the back that is imprinted with numbered codes to monitor product quality, as well as track the date and location of its manufacture.

The method used for testing shingle toughness and tear resistance is the ASTM D3462 performance standard. Underwriters Laboratories (UL)  conducts independent testing on CertainTeed shingles.

When you see the UL label on the packaging of shingles, you can have confidence that they meet this standard.

  • CertainTeed shingles are UL-listed prepared roofing material shingles — Class A
  • Degree of resistance to external fire and flammability limits in accordance with UL standard 790
  • Degree of wind resistance in accordance with UL standard 997 (when applied in accordance with instructions included with the roofing product)
  • Classified in accordance with ASTM D3462, including tear resistance

Copies of our UL certificate of compliance are available at, where you can also find out about all of our products and systems.

*Wind rating dependent upon shingle type and roof system configuration, for more information on our wind ratings please review our asphalt shingle warranty.