Can I Place a New Roof on Top of my Existing Shingle Roof?

Types of Roofing Shingles: Asphalt vs. Fiberglass

When it comes to residential roofing in Arizona, most homeowners choose between two main types of shingles: asphalt and fiberglass. Both options are widely used, but each has its own pros, cons, and ideal applications—especially in hot, dry climates like Phoenix. Below, we break down the key differences to help you make an informed decision for your next roof installation or replacement.

1. Asphalt Shingles

Asphalt shingles are the most common roofing material used in the United States. Known for their affordability and versatility, they offer reliable protection for homes in a range of climates—including the desert Southwest.

• • More Affordable: Asphalt shingles are budget-friendly and accessible, making them a go-to option for homeowners looking for a cost-effective roofing solution.
  • Variety of Colors and Styles: These shingles come in a wide range of colors, textures, and patterns, allowing you to match your roof to your home’s aesthetic.
  • Long-Lasting: Standard three-tab asphalt shingles typically last 20 to 30 years. With proper maintenance and professional installation, they can endure Phoenix’s harsh sun and monsoon seasons.
  • Architectural Upgrades Available: For those looking for a more high-end appearance, architectural asphalt shingles (also known as dimensional shingles) offer a layered look with enhanced thickness and depth.

Asphalt shingles are lightweight and relatively easy to install or replace. They’re also compatible with a wide range of roof slopes and home styles. While they may not offer the same performance as higher-end materials, their value and versatility make them a strong contender for most residential applications.

2. Fiberglass Shingles

Fiberglass shingles are a subtype of asphalt shingles but constructed with a fiberglass base mat instead of an organic one. This design upgrade gives them increased strength, longer lifespan, and improved fire and moisture resistance—key factors for homes in extreme environments like the Arizona desert.

• • Superior Durability: The fiberglass mat adds reinforcement that helps prevent warping, cracking, and curling over time.
  • Fire Resistance: Fiberglass shingles typically earn a Class A fire resistance rating, the highest rating available. This makes them one of the safest options for homes in high-temperature regions like Phoenix.
  • Moisture and Mold Resistance: Thanks to their non-organic core, fiberglass shingles are less prone to water absorption, which helps prevent mold and mildew buildup.
  • Lightweight: Despite their added strength, fiberglass shingles are lighter than traditional asphalt, which places less strain on your roof’s structure over time.

Although fiberglass shingles tend to cost more upfront than basic asphalt options, the long-term savings often offset the initial investment. Their resistance to extreme heat and UV rays makes them particularly effective in Arizona, where standard materials often deteriorate quickly under constant exposure to the sun.

3. What About Organic Shingles?

While not as commonly used today, organic shingles—like wood or paper-based shingles—were once a popular choice. However, they come with several drawbacks, especially in desert climates:

• • Lower Fire Resistance: Organic shingles are typically rated Class B or C for fire resistance, which is significantly less protective than fiberglass shingles.
  • More Prone to Rot: Organic materials can absorb moisture, leading to faster decay, mold growth, and structural damage over time.
  • Higher Maintenance: These shingles often require more frequent inspections and repairs to stay effective.

While wood shingles may offer a unique and rustic appearance, they’re not recommended for homes in Phoenix or other fire-prone, high-heat regions. For safety and performance, asphalt and fiberglass shingles remain the top choices.

4. Which Shingle Type Is Right for You?

Choosing between asphalt and fiberglass comes down to your budget, goals, and the specific demands of your home’s location. At KY-KO Roofing, we help homeowners navigate these decisions every day, offering expert recommendations tailored to their property and preferences.

Placing new shingles over your existing ones is possible. Remember that this is only recommended for certain roof damage. If you have significant signs of aging or water damage, your roofing contractor will likely advise a roof replacement.
You can save time and money on minimal roof damage by adding a second layer of shingles. Why? Most roof repairs require pulling off the old shingles and replacing them with new ones.
This increases labor-intensive costs and the price of disposing of the old materials. In most cases, this process is only done one time. If you experience damage in an area where the second layer of asphalt shingles was placed, you will likely need to remove and replace the old shingles.