While roofing shingles are usually referred to as asphalt shingles, they are not entirely made of asphalt. The composition can vary by manufacturer, but asphalt shingles usually consist of mineral fiber and cementitious fillers.

Let’s take a look at what roofing shingles are made from.

Fiberglass

Asphalt roofing shingles have a fiberglass foundation. Fiberglass is used as the backing material for shingles and is the base of a shingle.

Large fiber glass rolls are unwound when the roofing shingle production process starts and the other materials are bonded to the backing.

Asphalt

Asphalt is the basic water-resistant ingredient in asphalt shingles. The type of asphalt used in roofing shingles is a particularly hard material that requires a specialized refining process to achieve the hardness necessary.

The asphalt is then oxidized by blowing art through the hot asphalt, increasing its viscosity.

A fine mineral powder is then mixed into the asphalt which enables the roofing shingle to be tire and weather resistant. This asphalt “coating” is then pressed on the top and bottom of the fiberglass mat.

Granules

The most visible ingredient of asphalt shingles is the stone granule surfacing. Hard rock is crushed to a precise, granular size. Then the granules are applied to the part of the shingle that is not exposed.

The granules are then processed into various colors using ceramic firing to give them lasting colors on the exposed part. Some shingles can also include an algae-resistant granule that helps prevent discoloration caused by blue-green algae. Also, special “reflective” granules can be used to make shingles that are able to reflect a higher percentage of the sun’s energy. 

Sealant

A thermally-activated asphalt sealant is applied to the shingles to connect the shingles on the roof. A material called laminate is used on multi-layer shingles to bond the shingle layers together at the time of production. 

These adhesives are specially made to ensure that they activate at particular temperature ranges, holding the bond through the installation process and during winds and other stresses.