What Are Asphalt Shingles and What Are They Made Of?

by Dalton Kelly Marketing

Asphalt roofing shingles have been around for over a century. But lately, high-end composite shingles have gained tremendous popularity among homeowners. These shingles are made of three main materials - each having its own set of properties and benefits. Also known as architectural shingles, these shingles are created to prevent water damage, look beautiful, and stand the test of time.

How to Determine If You Have a Composite Shingle Roof?

If your roof is not made of natural roofing material, such as slate or cedar shingles, there are high chances that you have a composite roofing system. Composite shingles are installed in rows or courses in such a way that every shingle row overlaps the lower row to achieve watertight protection. These shingles need a slope or pitch to perform optimally. For this reason, flat roofs or low-slope roofs are commonly made of different materials.

To be an ideal candidate for composite shingles, your roof should have a pitch greater than 3:12. If your roof doesn’t have a waterproof underlayment, which is suitable for low-slope roofs, a pitch of 3:12 means that your roof has a vertical height or rise of 3 inches for every one foot or 12 inches. Composite shingle roofs are commonly available in pitches ranging between 4:12 and 12:12. The most common one is 6:12.

Fiberglass Asphalt Shingles:

Fiberglass asphalt shingles also have three layers: a fiberglass layer in the center consists of interwoven fiberglass strands, which are coated with asphalt layers on both sides and have protective granules on the exterior layer. Thanks to this special design, fiberglass asphalt shingles are durable, flexible, and have a low manufacturing cost. Let’s look at each of these layers in detail:

Fiberglass Strands

Most composite shingles, even high-end ones that are made to imitate other materials, are constructed using fine fiberglass strands. These flexible yet extremely resilient fiberglass strands provide each shingle with excellent tear resistance, crack resistance, and impact resistance properties.

Asphalt

The interwoven fiberglass is made into a mat that is coated with asphalt, or some other materials depending on the product. The asphalt layer provides each shingle with good flexibility and makes sure that each shingle maintains a strong bond with the shingles underneath it. Asphalt provides waterproofing properties to the shingles and plays a vital role in preventing leaks.

Granules

Each composite shingle is covered with protective granules on the exposed side. The granule layer is commonly made from a mixture of crushed stone particles, such as basalt, granite, or volcanic rock. This layer provides additional durability, impact resistance, and aesthetic appeal to the exposed part of the shingles for optimum protection against the elements.

Organic Composite Shingles

Organic shingles are not in production anymore. But they were renowned for their excellent protection against cold weather damage. These shingles were more popular in colder regions because they used to come with a thicker mat and two asphalt layers for protection against extreme cold.

However, one of their major drawbacks was that the volatile materials in these shingles tended to escape over time. And in absence of these materials, organic shingles started to lose their strength, durability, and flexibility over time. No wonder, older roofs made of organic shingles have become extremely vulnerable to weather elements after a few years.

Moreover, the leaching process accelerates even further in warmer climates. This usually leads to frequent repairs. In such cases, the thick mat in these shingles works against them because it allows them to absorb more moisture, resulting in serious water damage.

These shingles did not come with a fiberglass mat. Instead, the mat layer in these shingles was made from organic materials like wood, paper, and cardboard. The asphalt layer and granules were largely responsible for their water-resistant properties.

For more information, contact Watkins Construction and Roofing at 251-299-8151 in Gulf Shores, Spanish Fort, Foley, Fairhope, Robertsdale, and Orange Beach, AL.