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What are the Problems With Installing a Metal Roof Over Shingles?

Metal Roof Over Shingles problems

A new metal roof is a costly purchase, so it is evident that you want to save money wherever possible. Some homeowners achieve this by installing a new metal roof over shingles. Although this is feasible in certain situations, it has some problems.

This blog post will guide you through the pros and cons of installing a metal roof over shingles.

Can You Install a Metal Roof Over the Shingles?

Metal roof-overs have become an alternative roofing solution for homeowners looking to install new roofs. This innovative method involves installing a new metal roof directly over existing shingles, which provides several advantages over traditional roof replacement.

Pros of Installing a Metal Roof Over The Shingles

The main reasons why many homeowners consider installing metal roofs over their existing shingles are:

No Tear-Off Costs: One of the most significant advantages is that you don’t have to pay for the labor and disposal costs of removing the old shingles. This can save you several thousand dollars.

Lower Installation Costs: Because the process is quicker than a full tear-off and replacement, you’ll spend less on labor fees.

Faster Installation: The installation process is much quicker since you don’t need to remove the old shingles. This means your new roof will be ready sooner, causing less disruption to your daily life.

Better Energy Efficiency: The existing shingles add an extra layer of insulation. This can help keep your home warmer in winter and cooler in summer, potentially lowering your energy bills.

Environmental Benefits: By not tearing off the old shingles, you reduce the amount of waste being sent to landfills. This makes the project more environmentally friendly.

Cons of Installing a Metal Roof Over The Shingles

Though you may be considering the above reasons good enough to install a metal roof over your shingles, here are some problems that you may experience if you choose to do so: 

Structural Load: Adding a metal roof on top of shingles increases the weight of your roof. If your home’s structure isn’t designed to support this extra weight, it could cause problems like sagging or structural damage.

Unseen Issues: If your existing shingles have problems like rot, mold, or structural damage, these issues will remain hidden and unresolved. Over time, this can lead to more significant issues that can be costly.

Aesthetic Considerations: If the existing shingles are uneven or in poor condition, they can affect the new metal roof’s appearance. The metal roofing might need to be fixed, leading to a less attractive appearance.

Building Code Restrictions: Some local building codes do not allow installing a new roof over an existing one. If this is the case in your area, you would need to do a complete tear-off, regardless of the condition of your shingles.

Factors to Consider When Installing a Metal Roof Over Shingles

Metal Roof Over Shingles

When installing a metal roof over shingles, it is important to consider the following factors:

Building codes in your area

In each area, there are different building rules. Some require roofers to get licenses, and others have rules about roof layers.

Talk to your local building authority to ensure you follow the rules. There are often restrictions on the number of roof layers you can use. Most of the time, you can only have two pieces of roofing material.

You must remove one layer before adding another if there are already two. Some places require inspections for installation and cleanup to ensure legality.

State of the Roof

Hire a professional to scrutinize your current roof. Look for damage such as leaks, rot, mold, and structural issues. Fix these issues before adding another layer.

Make sure that the deck beneath the roof’s base layer is in good shape. A broken or weak deck might not support the new metal roof properly.

Roof Structure

Check to see if the structure you already have can support the extra weight of a metal roof. In this scenario, we will examine your home’s rafters, trusses, and overall structure.

If there are doubts about the building’s ability to hold the extra weight, you may need to strengthen the roof, making the job more difficult and expensive.


Make sure your roof has enough air flow to keep water from building up. This could mean adding or improving vents so that air can flow properly between the layers of the roof.

You might also want to put a moisture shield between the metal roof and the shingles to help stop condensation and other problems associated with it.

Aesthetic Preferences

Think about how the new metal roof will look on top of the shingles that are already there. When they aren’t level, the shingles can make the metal roof look wavy or bumpy. Metal roofs come in many styles and colors. Pick one that complements the exterior of your house and fits your style.

Costs Considerations

Considering materials, labor, permits, and possible upgrades, determine the total cost. Compare this to the cost of a full teardown to find the best deal.

Consider how much money you could save in the longer run by using less energy and possibly not having to fix your roof as often.

Challenges Faced while Installing a Metal Roof Over Shingles

Metal Roof Over Shingles

You may have heard it’s a good idea to put a metal roof over shingles. But it’s not really that great.

Problems with Permits

Collaborating with local building offices can be difficult. Obtaining the right permits usually requires a lot of paperwork and strict rules.

Setting up and passing inspections can slow down the job. Fixing any problems discovered during checks is necessary before the project can proceed, leading to increased time and cost.

Moisture buildup

Insufficient air flow can trap water between the metal roof and the shingles, forming fog. Over time, this can lead to mold, mildew, and rot. Adding or improving ventilation systems can be difficult, and you must plan carefully to ensure air flows well.

Structural Concerns

Adding a metal roof increases your home’s frame’s weight. If the framework wasn’t built to support this extra weight, it could damage the structure or even cause it to fall. Making the roof stronger can be expensive and may require major changes to your home.

Professional Installation

Some roofers don’t know how to put metal roofs over shingles. It’s important to find professionals who know how to deal with the unique problems that come with this type of work. Bad fitting can lead to leaks, poor ventilation, and structural issues.

Make sure the contractor has a history of successful installations and good recommendations.

Hidden Damages

If your roof has leaks, rot, or mold that you can’t see, they can get worse over time if you don’t fix them. We must find and fix these problems through a thorough inspection before installation.

Ignoring problems at their roots can cause significant damage that will cost more to fix in the future. Before putting on a new layer, it’s important to fix any problems with the old roof.

When Installing Metal Over Shingles, Will I Void My Metal Warranty?

You might be wondering if you would void your warranty if you put a metal roof over shingles. Like most things in life, the answer is “it depends.”

Some companies that make metal roofs will keep you from putting their products on top of shingles because that would void the guarantee. In some cases, the guarantee might not say anything about it. What should a homeowner do? It’s pretty easy.

Contact the metal roof company and ask about their guarantee. Also, check with the guarantee company to see if removing the old shingles is required. Always prioritize safety over regret. Make sure you know what you’re doing before you install a metal roof over shingles.

Can I Save Money Installing a Metal Roof Over Old Shingles?

There are different ways to look at it! Putting a metal roof over old shingles will save you money on labor and dump fees. On the other hand, it’s not always the best long-term answer. Also, remember how much it will cost to get rid of those old roofs.

Between $1,000 and $1,600 is how much it costs to get rid of your shingles and start over. That’s why you should think twice before switching from shingles to metal roofs.

Final Thoughts

Finally, having a metal roof over shingles might seem like a great idea, but it’s important to be aware of possible problems. You can get the most out of your metal roof if you stay alert, pay for proper installation and maintenance, and get professional help. Your house needs a strong, reliable roof that will last for a long time.

The best way to prepare for putting a metal roof over shingles is to remove the old shingles. Because of these issues, we don’t suggest people put a metal roof over shingles.

If you are sure a metal roof will work well, you might want to put one over a plain roof deck. We at Evoli Roofing have skilled, committed, and experienced metal roofers you can count on.



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