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Can you install a metal roof over asphalt shingles?

Yes, you can install a metal roof over asphalt shingles. Check local codes and assess your home’s structure first. Consult experts for moisture risks before proceeding.

Key Factors to Consider When Installing a Metal Roof Over Asphalt Shingles

person drilling nails on a metal roof

Before you install a metal roof over your existing asphalt shingles, it’s crucial to evaluate various factors that could impact the project’s success and long-term viability. From local regulations to structural considerations, here are the essential elements you need to consider:

  • Local Building Codes: Check your local laws and regulations, as some areas may require the removal of old shingles before installing a new roof.
  • Structural Integrity: Ensure your home has the structural capacity to support the additional weight of a metal roof.
  • Condition of Existing Shingles: Assess the condition of your current asphalt shingles; damaged or rotting shingles could compromise the new metal roof.
  • Moisture Barriers: Determine if a moisture barrier or underlayment is necessary to prevent water from getting trapped between the old and new roofing materials.
  • Ventilation: Verify that there is adequate ventilation in the attic or beneath the roof to prevent condensation and other moisture-related issues.
  • Cost Analysis: Weigh the financial pros and cons, considering the costs of removing old shingles versus installing the new metal roof directly over them.
  • Aesthetic Factors: Understand that the appearance of your new metal roof may differ based on the installation method and whether it’s layered over existing shingles.
  • Warranty Concerns: Research whether installing a metal roof over existing shingles will void any warranties you may have or intend to secure.
  • Environmental Considerations: Take into account the environmental benefits of installing over existing shingles, such as reducing waste that would otherwise go to a landfill.

How Does Roof Size Influence the Cost of Metal Roof Installation Over Asphalt Shingle?

drone view of roofs

The size of your roof significantly impacts the cost of installing a metal roof over asphalt shingles. Larger roofs require more materials and labor, increasing the overall cost. However, the cost per square foot may decrease for larger projects due to economies of scale. Always get a detailed estimate based on your specific roof size. You can use our Roof Cost Calculator for free.

Advantages of a Metal Roof On Top of Existing Asphalt

Installing a metal roof over existing asphalt shingles offers several advantages that can make this option appealing to homeowners. Not only can it be a cost-effective and time-saving solution, but it also has environmental and durability benefits. We wrote a more in-depth blog post on metal roofs being better. Because in many ways they are! Here is a brief summary of their advantages.

Durability and Lifespan

Metal roofs outshine asphalt shingles in both durability and lifespan. While asphalt may last up to 30 years, a metal roof can last from 40 to 70 years. Metal is also more resilient, holding up well against harsh weather conditions like hail and high winds. This means fewer repairs and greater peace of mind for homeowners.

Energy Efficiency

Metal roofs are more energy-efficient than asphalt, reflecting heat and lowering cooling costs. In the blazing heat of Arizona and Florida, these roofing materials prove invaluable. Similarly, the unpredictable weather in Oklahoma often means homeowners find themselves in need of roof replacement in Oklahoma expertise more often than in other states. Always check local codes and needs.

Noise Levels

One often overlooked advantage of installing a metal roof over asphalt shingles is noise reduction. Many people assume metal roofs are louder, especially during rain or hail. However, when properly insulated, a metal roof can actually be quieter than its asphalt counterpart. The existing layer of asphalt shingles can also act as an additional sound barrier, further reducing noise levels in your home.

Disadvantages and Risks

Though initial costs and moisture risks exist, installing a metal roof over asphalt shingles can be a wise long-term investment. The durability and energy savings often outweigh the upfront expenses, making it a financially sound choice in the long run.

Potential Moisture Issues

When installing a metal roof over asphalt shingles, moisture control is crucial. Poor installation can trap water between the layers, leading to issues like mold, rot, and rust. These problems not only compromise your roof’s integrity but can also lead to costly future repairs and reduced energy efficiency. Therefore, proper moisture barriers and installation techniques are essential.

Increased Costs

Another downside of installing a metal roof over asphalt shingles is the potential for increased costs. While you may save on shingle removal, metal roofing materials can be more expensive upfront. Additionally, installing a metal roof often requires specialized labor, which can further elevate the initial expenses. Therefore, it’s crucial to weigh these costs against the long-term benefits.

When to Consult a Professional

person inspecting roof

Consulting a professional is advisable at several stages when considering the installation of a metal roof over existing asphalt shingles. Here are some key moments:

  • Initial Assessment: Before making any decisions, have a professional evaluate the condition of your current asphalt shingles and the structural integrity of your home.
  • Code Compliance: A roofing expert can guide you through local building codes and regulations, helping you understand what is allowed in your area.
  • Cost Estimates: Professionals can provide detailed cost analyses, allowing you to weigh the financial pros and cons effectively.
  • Material Selection: An expert can help you choose the right type of metal roofing material that fits both your needs and your budget, offering insights into metal roofing costs.
  • Installation: The actual installation should be performed by professionals, especially since metal roofing requires specialized skills and tools for proper fitting.
  • Final Inspection: After the installation, a professional can conduct a thorough inspection to ensure everything has been done correctly and that the new roof is secure.


In conclusion, installing a metal roof over existing asphalt shingles can be a smart choice for long-term durability and energy efficiency. Yet, it’s crucial to consider the upfront costs and potential moisture issues.

Consulting with professionals and adhering to local building codes will help mitigate risks and ensure a successful project. Doing your due diligence upfront can lead to years of peace of mind and a sound investment in your home’s future.

Fact checked by Christinne Somo – 9/22/23