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Can You Install a Metal Roof Over Existing Shingles? Exploring the Pros and Cons

When it comes to roofing options, metal roofing has gained popularity for its durability,

Metal Roof Over Shingles

energy efficiency, and aesthetic appeal. If you're considering upgrading your roof to metal, you may be wondering whether you can install it over your existing shingles. In this blog post, we'll explore the pros and cons of installing metal roofing over shingles to help you make an informed decision.


Pros of Installing Metal Roofing Over Shingles:


1. Cost Savings:

One of the significant advantages of installing metal roofing over shingles is cost savings. Removing the existing shingles can be a labor-intensive process, requiring both time and money. By installing metal roofing over the shingles, you can eliminate the need for tearing off the old roof, saving on disposal costs and labor.


2. Time-Efficient Installation:

Metal roofing over shingles can be a quicker installation process compared to a full roof replacement. The existing shingles provide a stable base, and the metal panels can be installed directly over them, reducing the time and effort required for the project.


3. Insulation Benefits:

The layer of shingles underneath can provide an additional insulation barrier, enhancing the energy efficiency of your home. This added insulation can contribute to better temperature regulation and potentially lower energy bills.


4. Environmental Considerations:

Choosing not to remove the existing shingles means less material ending up in landfills. If you are environmentally conscious, installing metal roofing over shingles aligns with sustainable practices by reducing waste.


Cons of Installing Metal Roofing Over Shingles:


1. Warranties:

Some metal roofing manufacturers may void their warranties if the metal panels are installed directly over shingles with no barrier between the two systems. Before proceeding with this installation method, it's essential to check the warranty terms and conditions to avoid potential issues down the line.


2. Uneven Surface:

Shingles can deteriorate unevenly over time, leading to an uneven surface for the metal roofing installation. This unevenness can affect the appearance of the new roof and result in unsightly oil canning.


3. Hidden Issues:

Installing metal roofing over shingles may hide underlying issues such as rot, water damage, or structural problems. Addressing these issues may require a complete roof tear-off to assess and remedy any damage.


Frequently Asked Questions:


Q: If I decide to put my metal roof over existing shingles, do I need a barrier between them?

A: Yes. You should install a synthetic underlayment and consider furring strips to create a barrier between the rough surface of the shingles and the primer on the underside of your metal roofing panels. This will prevent the primer from being agitated by the shingles as your metal roof naturally expands and contracts. Popular barriers included furring strips, retro-ease spacers, or shingle re-cover systems that are compatible with some standing seam metal roofing systems.


Q: Will installing a metal roof over shingles add too much weight to my roof?

A: Metal roofing is about 1/3 of the weight of asphalt shingles. However, you should never consider installing a metal roof over more than one existing layer of shingles (this is typically always against code anyway).


Q: Will installing a metal roof over shingles make my house hot?

A: Metal roofing is extremely energy efficient and is highly effective at reflecting solar energy away from your home which helps keep it cool.


Conclusion

While installing metal roofing over shingles can offer cost savings and a faster installation process, it's essential to carefully consider the potential drawbacks. Assessing the condition of your existing roof, checking warranty implications, and consulting with roofing professionals are crucial steps in making an informed decision. Whether you choose to install metal roofing over shingles or opt for a complete tear-off, prioritizing the long-term health and performance of your roof is key to a successful metal roofing project.

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