What Are Roof Shingles Made Of?
Modern roof shingles are more than just a covering; they’re an essential part of your home’s weather protection system. If you’ve ever wondered what roof shingles are made of, the answer is both simple and surprisingly high-tech. While many materials exist, like wood shakes, slate, metal, and synthetic blends, the most common roofing shingles across the U.S. are made from asphalt. But there’s a lot more going on beneath the surface.
Let’s take a closer look at how these shingles are made and what materials go into creating this lightweight, durable, and weather-resistant roofing solution.
How Are Asphalt Roof Shingles Made?
Asphalt shingles are the most widely used roofing material in the United States, covering over 70% of residential roofs. They’re affordable, durable, fire-resistant, and effective in all kinds of weather, which is critical in a climate like Toledo’s with its freezing winters and hot, humid summers.
The typical asphalt shingle is made using a continuous, multi-layer manufacturing process designed for both strength and weather protection.
1. Fiberglass Mat
At the core of every asphalt shingle is a fiberglass mat, which provides structural integrity and flexibility. This mat is made by weaving together tiny glass fibers into a strong, flat sheet.
- These fibers are bound with resins and binders.
- The resulting mat is lightweight but incredibly strong.
- It resists moisture, rot, and warping over time.
Large rolls of fiberglass mat are prepared at mills, then unrolled at the start of the shingle production line to serve as the foundation layer.
2. Asphalt Coating
The next ingredient is asphalt — a waterproofing agent derived from refined petroleum.
But this isn’t the same asphalt used in roads. Roofing-grade asphalt is treated by blowing hot air through it. This:
- Thickens its consistency (increases viscosity)
- Makes it tougher and more durable
- Allows it to bond effectively with granules and fiberglass
A mineral stabilizer (usually limestone powder) is mixed into the asphalt to make it more resistant to UV rays, fire, and weathering. Then, it’s applied to both the top and bottom sides of the fiberglass mat.
3. Granules
If you’ve ever seen the textured surface of a roofing shingle, those are mineral granules, small, colored stones crushed from hard rock.
These granules serve several purposes:
- Protect the asphalt from sun damage and wear
- Add colour and style options
- Improve fire resistance
They’re often ceramic-coated through a high-temperature firing process, which locks in colour and enhances durability.
Some shingles even feature:
- Algae-resistant granules: Prevent blue-green algae stains, especially in humid areas.
- Cool roof granules: Designed to reflect sunlight and reduce heat absorption, required in some energy-efficient building codes.
4. Sealant
A thermally activated sealant strip is applied to the shingles, typically on the underside. This sealant:
- Activates under the sun’s heat once installed on a roof
- Bonds shingles together to resist wind uplift
- Adds a watertight seal between layers
For multi-layered laminated shingles (also called architectural shingles), a laminate adhesive is used during production to hold the layers together permanently.
5. Back-Surfacing
Asphalt shingles are naturally sticky due to the asphalt coating. To prevent them from sticking together during production or storage, a fine layer of mineral powder is applied to the back of the shingle. This is typically made from:
- Fine sand
- Crushed limestone
- Other rock-based powders
This back-surfacing is important during manufacturing and packaging, but does not affect the shingle’s performance once installed.
6. Release Film
To prevent the shingles from bonding inside the bundle before installation, manufacturers apply a thin plastic release film over the sealant strip.
- It prevents premature activation during storage and shipping.
- Once installed and exposed to the sun, the film serves no further function and remains on the back of the shingles.
Roofing Shingle Composition at a Glance
| Material | Purpose |
|---|---|
| Fiberglass Mat | Strength and shape |
| Asphalt | Waterproofing and fire resistance |
| Mineral Granules | UV protection and colour |
| Sealant Strip | Wind resistance and bonding |
| Back-Surfacing | Prevents sticking in packaging |
| Release Film | Prevents early sealant activation |
Why Every Material Matters
While asphalt shingles might appear simple, every component is chosen and engineered to work together. The result is a roofing material that is:
- Waterproof
- Fire-resistant
- Lightweight
- Durable under extreme weather
- Cost-effective for homeowners
The combination of fiberglass strength, asphalt waterproofing, protective granules, and intelligent sealing makes today’s shingles more advanced than ever before.
Why It Matters for Toledo Homeowners
Toledo weather can be rough – snow, wind, sun, and ice all take a toll on your roof. Knowing what shingles are made of helps you:
- Choose longer-lasting materials
- Know when a roof replacement is worth it
- Understand if the damage is cosmetic or structural
Frequently Asked Questions
Q: Are asphalt shingles waterproof?
Yes, the asphalt layer creates a strong water-resistant barrier.
Q: Do shingles contain fiberglass?
Most modern shingles are built on a fiberglass mat for strength and flexibility.
Q: What are the granules on shingles for?
They protect against UV rays, enhance fire resistance, and add colour.
Final Thoughts
In short, modern asphalt roof shingles are engineered systems, not just simple layers of tar and rock. Each layer and material plays a key role in making sure your roof stands up to rain, wind, heat, and time.
Understanding what goes into these shingles can help you make better decisions when choosing materials, hiring contractors, or planning a replacement.
Need a Roof Repair or New Installation in Toledo?
At ProCraft Home Products, we’ve built a trusted reputation in the Toledo area by combining:
- High-quality roofing materials
- Experienced local installers
- Honest, no-pressure inspections
Call us at 419-475-9600 or visit our office at 1622 Coining Dr, Toledo, OH 43612 for a free estimate. We’ll help you choose the right shingles and make sure they’re installed to last.
