What Are Shingles Made Of? (Homeowner’s Guide)

Posted By: Chrissie Litenski

The majority of homeowners across the United States have asphalt shingle roofing, which means you likely do too. The reason behind the popularity of asphalt shingles is that they’re versatile, cost-effective, and widely available. They’ll also last between 20 and 30 years on average, making them a worthwhile investment.

But what are shingles made of, exactly?

If you’ve ever wondered about what your roofing shingles are made of, you’ve come to the right place. Below we’ll explain everything you need to know about the raw materials that go into the most popular type of roofing — so that when the time comes for a roof replacement, you’ll know whether or not you’re making the right decision.

Asphalt Roofing Shingles: The Material Breakdown

Choosing the right type of roof shingles can go a long way in preventing early deterioration and other common roofing issues. While asphalt shingles aren’t you’re only option, they’re the most common and the most affordable — and there are several types you can choose from:

3-tab shingles
Architectural (or dimensional) shingles
Luxury shingles

While each type of asphalt roofing shingle is a bit more durable and aesthetically pleasing than the next, the biggest thing they have in common is that they’re made of the same stuff. Here’s what goes into these different types of asphalt shingles:

1) Fiberglass

The manufacturing process for these roofing shingles works like a continuous web (or sheet) to provide a stable foundation on which the raw materials can be applied to. The first material in this sheet is a thin, fiberglass mat that is made from glass fibers of a specific length and diameter.

The glass fibers are first bound together using stable resins and other binders, creating the fiberglass.
The fiberglass is then wound into large rolls that can be sent directly to the shingle manufacturer.
The shingle manufacturer “unwinds” the roll at the beginning of the manufacturing process — hence the stable foundation.

Essentially, the fiberglass mat with its binders and resins is designed to not only provide a foundation but reinforce the asphalt shingles once they’re complete.

2) Asphalt

As the name implies, asphalt is the primary component of asphalt rofing shingles. It’s what makes them water-resistant as asphalt itself is a byproduct of oil refining that’s processed to the highest degree of toughness.

Roofing asphalt must first be oxidized, which is done by blowing air through hot asphalt to increase viscosity.
A fine mineral powder is then mixed with the thickened asphalt to increase its weather resistance and fire resistance.
This mixture creates what is referred to as a “mineral-fortified asphalt coating”, which gets applied to the top and bottom of the fiberglass mat.

Despite their rugged texture, the blowing process for asphalt roofing shingles is delicate. Too much air blown through the asphalt will cause the shingles to turn out too brittle. Too little and the shingles will turn out soft and prone to damage.

3) Granules

The little stone granules are the most visible component of asphalt roof shingles. They’re essentially made from hard rocks that have certain physical properties that allow them to be crushed and screened to a specific size while still maintaining the strength to protect the shingles.

Granules are applied in a two-step process:

In the part of the roof shingles that are not exposed, the granules are applied in their natural state — meaning that their natural stone color remains. Of course, they’re still ground and screened into equally sized pieces.
In the part of the roof shingles that are exposed, the granules — also referred to as grit — are processed into a variety of colors. This is done with the help of ceramic firing, which is what gives these granules their long-lasting colors.
Depending on the shingle type, you can opt for algae-resistant granules that inhibit the discoloration that occurs due to blue-green algae growth.
There are also special reflective granules that are designed to reflect more of the sun’s UV rays and heat energy for better temperature regulation and durability.

Granules also act as a first line of protection against not only the elements but weather events. In most cases of significant storm damage, you’ll notice that your granules are the first to go.

4) Sealant

In order to bond the asphalt shingles roof together from start to finish, there’s a thermally-activated sealant that’s applied. First, the sealant is applied to the various shingle layers to ensure the bonds of each component are protected and that the desired temperature range remains consistent throughout.

This sealant is also applied to certain areas of each shingle upon installation, depending on where they’re being placed.

The shingles that are installed closer to the roofs’ ridges and eaves will have the sealant applied on the bottom.
The shingles that are getting installed closer to the roof’s peak will have the sealant applied to both the bottom and top surfaces to help them adhere to the underlying roof building materials and each other as they’re layered.

Generally speaking, asphalt coating material is going to be sticky. The sealant also provides support known as “back surfacing”, which is essential to prevent the asphalt rolls from sticking during the manufacturing process.

5) Release Film

The final component of all asphalt shingles is the release film. As mentioned above, the sealant used for bonding is thermally activated, which means that all it takes is a sufficient amount of solar heat for the asphalt rolls to become a sticky mess. The release film is what prevents this from happening while the asphalt shingle rolls are being stored.

Release film looks like a type of shiny plastic tape or backing that’s roughly an inch wide, and it’s applied to the back of the asphalt shingles.
The release film works only while the shingles are still in their package as it’s designed to keep them from bonding with one another prematurely.
Once the asphalt shingles are installed onto the roof, the film simply sits on the back of the shingle.
The release film is not meant to be peeled off, and it’s incredibly difficult to do so — but, it’s a mistake that many rookie roofers make!

Thinking About New Roofing Shingles?

While asphalt roofing shingles aren’t your only option, it does tend to have the most components involved in its making. Now that you know what asphalt roofing shingles are made of, it’ll be much easier to understand what your roofing contractor is explaining to you when they’re talking about various types of asphalt shingle roofs.

Whether you want to stick with asphalt roofing shingles or want to learn more about your other roofing material options, the experts at Distinctive Roofing can walk you through all of the available options and help you make the right choice. Get started by booking your free roof inspection today!