5 Problems With Installing a Metal Roof Over Shingles

5 Problems With Installing a Metal Roof Over Shingles

Installing a metal roof over shingles may seem like a cost-effective and time-saving solution for homeowners looking to upgrade their roofing system. While this method can work in some cases, it also comes with significant drawbacks that could lead to long-term issues. Before making a decision, it’s essential to understand the potential risks and challenges involved in layering a metal roof over an existing shingle roof.

At S&K Construction and Remodeling LLC, we provide expert roofing services across Youngstown, Ohio, and surrounding areas, including Twinsburg, Lakewood, Medina, Wickliffe, Cleveland, Cleveland Heights, Euclid, Willoughby, Beachwood, Chagrin Falls, Chardon, Concord, Gates Mills, Kirtland Hills, Madison, Mayfield Heights, Pepper Pike, Walton Hills, and Lyndhurst. As an Owens Corning Preferred Contractor, we believe in educating homeowners about the best roofing practices to ensure long-lasting protection and performance.

1. Potential Structural Issues

One of the biggest concerns with installing a metal roof over shingles is the additional weight. While metal roofing is relatively lightweight, adding a second roofing layer can still put excessive stress on the home’s structure, especially if the existing roof is already aging or has underlying damage.

Why It’s a Problem:

• If the roof structure cannot handle the extra weight, it may cause sagging or structural failure over time.
• Hidden issues such as rotting wood, weakened decking, or water damage may remain undetected under the new roof.
• Building codes in some areas limit the number of roof layers allowed before a full tear-off is required.

2. Trapped Moisture and Condensation Risks

Metal roofs are highly durable and resistant to harsh weather, but when installed over shingles, they can trap moisture between the layers, leading to mold, mildew, and rot. Shingles naturally hold moisture, and without proper ventilation, this can cause problems beneath the metal roof.

Common Moisture-Related Problems:

• Condensation buildup between the shingle and metal layers, leading to corrosion or water damage.
• Shingle deterioration due to lack of airflow and excessive heat retention.
• Mold growth that can spread to the home’s insulation and interior spaces.

A properly installed metal roof requires adequate ventilation to prevent moisture buildup and extend the lifespan of the roofing system.

3. Uneven Surface and Installation Challenges

Shingles are not a perfectly smooth surface, and layering metal panels over them can lead to an uneven and unstable installation. Over time, this can cause fastening issues and structural weaknesses.

Installation Issues to Consider:

• Shingles warp and curl over time, creating an irregular surface for the metal roof.
• Without a solid, smooth underlayment, the metal roofing panels may not secure properly, leading to loose panels, leaks, or premature failure.
• Some manufacturers may void warranties if metal roofs are installed over existing shingles without the proper preparation.

4. Reduced Energy Efficiency

Metal roofs are known for their energy efficiency due to their reflective properties, which help deflect sunlight and reduce heat absorption. However, when installed over shingles, the benefits can be compromised due to poor ventilation and trapped heat.

Energy Efficiency Concerns:

• The existing shingles absorb heat, causing the attic space to retain warmth rather than dissipate it efficiently.
• Without a proper radiant barrier or insulation layer, homeowners may lose out on the cooling benefits that metal roofing provides.
• Higher attic temperatures can lead to increased energy costs in the summer months.

A well-installed metal roof should include a breathable underlayment and proper ventilation to maximize its energy-saving benefits.

5. Voided Warranties and Code Compliance Issues

Many roofing manufacturers and local building codes have specific guidelines on how metal roofs should be installed. Placing a metal roof over an existing shingle layer can sometimes void the manufacturer’s warranty and create compliance issues with local regulations.

Potential Consequences:

• Voided warranties: Many manufacturers require proper tear-off and underlayment installation to maintain coverage.
• Insurance concerns: Some insurance companies may not cover damage if a metal roof was installed over shingles in a way that violates building codes.
• Code violations: Certain municipalities and counties restrict multiple roofing layers due to weight, safety, and ventilation concerns.

Before proceeding with a metal roof installation, always check local building codes and consult with experienced professionals like S&K Construction and Remodeling LLC to ensure compliance and warranty protection.

Why Choose S&K Construction and Remodeling LLC for Your Roofing Needs?

At S&K Construction and Remodeling LLC, we prioritize quality craftsmanship, safety, and long-term performance. Here’s why homeowners across Northeast Ohio trust us for their roofing projects:

✅ Expert Roof Inspections – We thoroughly assess your existing roof’s condition to determine the best installation approach.

✅ Professional Metal Roofing Installation – We follow industry best practices to ensure your metal roof is installed correctly, safely, and in compliance with local building codes.

✅ Owens Corning Preferred Contractor – Our team meets the highest standards in the industry, providing homeowners with peace of mind.

✅ Comprehensive Roofing Solutions – Whether you need a tear-off and replacement or a professional second-layer installation, we provide the best recommendations for your home’s long-term health.

Areas We Serve

We proudly provide expert roofing services in:

• Twinsburg
• Lakewood
• Medina
• Wickliffe
• Cleveland
• Cleveland Heights
• Euclid
• Willoughby
• Beachwood
• Chagrin Falls
• Chardon
• Concord
• Gates Mills
• Kirtland Hills
• Madison
• Mayfield Heights
• Pepper Pike
• Walton Hills
• Lyndhurst

Final Thoughts: Is Installing a Metal Roof Over Shingles a Good Idea?

While installing a metal roof over shingles can be done, it comes with several potential issues that homeowners should consider before moving forward. Trapped moisture, structural concerns, energy efficiency loss, uneven surfaces, and warranty complications can all impact the long-term performance of your roof.

For the best results, working with a trusted, professional roofing contractor is essential. At S&K Construction and Remodeling LLC, we ensure that every roof installation—whether metal or asphalt—is done with precision, compliance, and long-term durability in mind.

📞 Contact us today for a free consultation and expert advice on your next roofing project!