Can You Put A Metal Roof Over Shingles?

A roof replacement is a significant investment that involves labor-intensive work, and this single project can cost thousands of dollars. Because of this, homeowners often look for ways to reduce the cost of a roof replacement. One way is to install a metal roof over existing shingles. If you are a homeowner thinking of installing a metal roof over shingles, you may have doubts regarding whether it is a good practice or just a temporary fix. 

The answer to the question, can you put a metal roof over shingles, is technically yes, but it isn’t a good idea. The expert roofers at Kickapoo Roofing don’t recommend installing a metal roof over shingles. Though metal roofs are lightweight and can be easily affixed on top of existing roof shingles, there are severe drawbacks that can trouble you later on. In this blog post, we discuss this topic in depth to help you make an informed decision.

Is It Okay To Install A Metal Roof Over Shingles? 

Though some homeowners install a metal roof over shingles, this isn’t a good practice for many reasons. Installing a metal roof over shingles can be an appealing solution to cut through the labor cost involved in removing old shingles and disposing of them, but it isn’t a healthy choice for your roof and can cost you more in the long run. Here are some potential drawbacks of installing a metal roof over a shingles roof.

Challenges of Installing a Metal Roof Over Shingles

If you choose to install a metal roof over a shingle roof, you may face the following disadvantages. Consider these drawbacks before making any financial decision about your roof. 

1. Hides Potential Damage To The Roof Deck 

Installing a metal roof over shingles can hide any potential damages on the roofing deck, which if not fixed may even cost you more later on. It can be difficult to address these issues under two layers of roofing materials, making repairs more expensive and time consuming. 

2. It Can Trap Moisture 

One of the primary concerns when installing a metal roof over shingles is proper ventilation and moisture control. Moisture can get trapped between the two roofing materials, which can later pose potential problems to the roof and the occupants. 

In addition, the trapped moisture between the two roofing materials can accelerate mold and mildew growth —another concern for homeowners.

3. It May Void Your Roofing Warranty 

Homeowners choose to install a metal roof over shingles at the end of the existing roof’s lifespan, but it can impact the warranty coverage that you may receive when choosing a complete roof replacement or roof repair. Some metal roofing manufacturers may void warranties if their products are installed over multiple layers of roofing materials or if specific installation requirements are not met. 

It’s important to review the warranty terms and consult with the manufacturer or a roofing professional to understand any limitations or restrictions related to the installation process.

4. May Damage The Aesthetic Appeal Of Your Roof

The condition of the existing shingles can affect the final appearance and performance of the metal roof. If the shingles are uneven or damaged, they may create an uneven surface that compromises the installation of the metal panels. Moreover, any trapped heat between the shingles and the metal panels can cause a cupping effect that creates metal roof oil canning. Oil canning can severely damage the aesthetic appeal of your roof. Surface preparation, such as repairing or replacing damaged shingles and ensuring a smooth substrate, is essential to achieve a professional-looking and durable finish.

5. Added Weight On The Roofing Structure

Though asphalt shingles and metal roofs are lightweight, when combined together, they can add extra weight to the roofing structure. This added burden places stress on the roof’s framing and support system, potentially leading to structural issues if not adequately addressed. 

So, before contemplating installing a metal roof over existing shingles, it’s crucial to assess the structural integrity of the underlying roof. 

Final Thoughts

Installing a metal roof over shingles can offer several benefits, including cost savings. However, it’s important to carefully consider factors such as structural integrity, ventilation, compatibility of materials, building codes, warranty implications, and surface preparation before proceeding with the installation. By addressing these key considerations and working with a qualified roofing professional, homeowners can ensure a successful and long-lasting metal roofing system.

Should You Install A Metal Roof Over A Shingle Roof? Consult a Roofing Professional

Installing a metal roof over shingles can be a cost-effective choice, but as this blog post mentions, it can cause significant damage to both the roof structure and the home. Whether you can put a metal roof over shingles or not, this decision depends on many factors, including the current age of your roof, its load bearing capacity, your budget, and your financial goals. 

So, if you are ready to make this significant financial decision, schedule a professional roof inspection with the expert roofers at Kickapoo Roofing in La Crosse, WI. Contact us today at (608) 352-8688 and talk to a professional for your roofing needs. 

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