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5 Common Issues With Metal Roofs Over Shingles

Posted on February 15, 2024

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5 Common Issues With Metal Roofs Over Shingles

Today, many homeowners admire metal roofs for their durable and stylish features. However, homeowners are also well aware that the cost of replacing a roof is quite high, causing them to search for alternatives that will reduce the cost of their roofing project. This is where many get the idea to simply install a metal roof over their old shingle one.  

However, we’re here to tell you that if you are replacing your asphalt shingles with a metal roof, it’s best to discard the old and damaged shingles before installation. An experienced and ethical roofing professional will not recommend homeowners install metal roofs over shingles as it can cause multiple problems. In this blog post, we’ll discuss these problems, their consequences, and the right ways to proceed with your project.

Installing A Metal Roof Over Shingles: Problems and Consequences For Homeowners

Roofing isn’t just about creating a strong and appealing shelter. It’s also about keeping the house comfortable and energy efficient throughout the year. For that matter, metal roofs are one of the most energy-efficient and durable materials for homes. Moreover, they make your home look unique and offer much better protection than asphalt shingles.

However, if the installation is not right, problems can arise after some time that are expensive to fix. Here are some common issues with installing a new metal roof over old roofing shingles:

Metal Roof Over Shingles

Problem #1 Improper Ventilation

Having multiple layers of different roofing materials hinders the roof’s ability to ventilate hot air from the home. It will also be hard to consider the ventilation needs of your home when there is an additional layer of roofing material. 


Improper ventilation puts an extra load on your heating and cooling units to maintain the desired, consistent atmosphere inside. When compromised, it leads to increased energy bills, uncomfortable temperatures, and high humidity inside the house.

Problem #2 Rust and Corrosion

Since asphalt shingles are designed to breathe and release moisture, covering them with metal roofing can inhibit this process, leading to moisture accumulation. Metal roofing panels begin to rust at the bottom due to trapped moisture between the shingles and panels. This compromises the strength of the panels and reduces the expected lifespan of the metal roof.


Rust and corrosion compromise the roof’s ability to withstand the elements, increasing the risk of leaks and damage during severe weather conditions. Moreover, if your metal roof expires way before its average lifespan, the overall purpose of durable roofing has failed. You will need a new roof once again, which is an expense that could have been avoided.

Problem #3 Warranty Voidance

Warranties act as a safety net, promising protection against unforeseen problems. However, if you have installed a metal roof over shingles, it most likely does not align with the terms of the warranty for the roofing materials. Manufacturers often have specific guidelines, and deviating from these can render your warranty null and void, leaving you solely liable for any future issues.


In the absence of warranty coverage, you are left financially responsible for the repairs and replacements of your new roofing materials. Even if you find a manufacturing defect, it’s possible that the company may hold you accountable for the improper handling and installation of the roofing materials.

Problem #4 Insurance Claim Complications

Insurance policies often have specific clauses related to roofing materials and installation methods. Installing a metal roof over damaged shingles does not align with the preferences of most insurance companies. Failure to adhere to their requirements results in complications when filing claims for roof damage.


If your insurance company does not provide partial, or any coverage for the damage, you will need to repair or install an all-new roof out of your own pocket. This can put you in an unexpected financial burden. Fortunately, you may have the option to discuss roof financing plans with a reliable contractor in your area.

Problem #5 Excessive Weight

Putting a metal roof over shingles creates a thicker layer of roofing material that adds weight that may weaken the wooden structure of your roof and attic walls. If your roof is not able to handle the weight of the shingles and metal panels together, it can become damaged, develop leaks, and even collapse unexpectedly.


Roof collapse is a risky accident that can damage your property and threaten the safety of your family. Heavy wooden beams and decking boards can fall down in the attic and damage the floor. If this happens during a storm, roofing materials can even cut through the ceiling!

The Right Way To Replace Shingles With A Metal Roof

Follow these expert tips to ensure your roof replacement is successful and your new metal roof is perfectly fine:

Proper Installation

Homeowners should prioritize hiring licensed and experienced metal roofing professionals for the installation of a new metal roof. Make sure the contractor is well-established and has a good reputation in your area. 

Prioritize the complete removal of your asphalt shingles before installing the metal roof. Also, choose an underlayment and insulation that is compatible with your metal roof. This ensures a clean, even surface for the metal panels and prevents issues we’ve discussed above.

Improve Attic and Roof Insulation

Consult a metal roofing professional to ensure the right balance of insulation and ventilation, creating a comfortable and energy-efficient attic space. Install vents and ventilation products designed for metal roofs. These include ridge vents, gable vents, and other options that facilitate efficient airflow and cooling.

Installing a metal roof correctly and making sure the attic gets enough air helps fix current problems and makes the roof last longer. It’s all about doing things right from the start to avoid issues and the need to spend more money later. 

If you need a metal roof installation or asphalt shingle replacement in Southeastern Pennsylvania, you can trust your local experts at North Star Roofing.

Schedule A Free Consultation With Our Shingle and Metal Roofing Experts!

At North Star Roofing, we’re proud to be owned and operated right here in Pennsylvania, which is why we know the importance of a strong and durable roof. The weather here is demanding, and proper installation is necessary to keep your roof protective and beautiful for years to come. If you want to replace your old asphalt shingles, we’re here to help you out. 

North Star Roofing is proud to be among the most reliable and experienced metal roof installers in Lansdale and surrounding areas of PA, and we’d be excited to upgrade your roof with your chosen metal roofing panels. Plus, we’re able to suggest the best roofing materials for your home, whether it’s metal or premium shingles from DECRA Metal Roofing or DaVinci. So, call us at (484)-302-7663 to schedule a free consultation with one of our experts and learn more.

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