Can You Put A Metal Roof Over Shingles?

Tom Gaffey
by Tom Gaffey

Roofs come in all sorts of materials, and each type has a different method of installation and expiration date. If you are looking to change up your roof, you are likely painfully aware that the process can involve significant labor and lots of money.

So, if you are looking to change out an old shingled roof for a brand new metal roof, you might want to know if you can install the metal roof over the existing shingles.

In many cases, it is perfectly acceptable to install a new metal roof over your existing shingle roof. Before you install the roof, however, check your local building codes to make sure this type of project is permitted where you live.

Make sure there are no leaks, mold or other issues with your existing roof, as these problems will likely worsen if covered.

If you want to install a new metal roof on your existing roof, you might be able to skip the labor-intensive process of removing your existing shingle roof. This process can not only save you lots of time, but the monetary saving might also be significant.

Before you pursue this process, however, make sure you read this article so you understand the pros and cons of doing this. Because although this can be a time and money saver, it is not always a good idea. In fact, sometimes it isn’t even allowed.

Things To Consider Before Putting A Metal Roof Over Shingles

When you start to mentally prepare for a new metal roof, there are some steps you should take before beginning this project. This is especially true if you are planning on installing a metal roof over an existing shingle roof.

Take the following issues into consideration before you decide to install a new metal roof over your existing roof.

Check Your Current Or Future Warranty

Is your current roof insured? What about the metal roof you are about to install? Make sure you are aware of any and all roof warranties. If you install one roof over another, there is a chance that these warranties might be void.

So, before you start the installation, double check this, as you definitely want to maintain your roof’s warranty as long as possible.

Are There Any Problems With Your Shingle Roof?

Perhaps the most important factor to consider is whether or not your shingle roof is experiencing any issues. If, for example, it is leaking or shows other signs of wear and tear, it should be removed.

Mold and rot might have already formed. As you may or may not already know, rot and mold can not be left unchecked. It must be removed completely or it will continue to spread.

Make Sure The Home Can Take The Extra Weight

Metal roofs are light, which is one of their great benefits. But while they are lighter than shingles, they still have some weight to them. Make sure this added weight is not going to be an issue for your roof. Check to see how much of a load your roof can withstand and then plan accordingly.

Consult Local Building Codes Before Installing The Roof

In many areas, there is no issue when it comes to installing a new metal roof over existing shingles. But not all municipalities have the same rules. So, before you purchase any roofing materials or hire a roofer to help you with the installation, make sure it is all legal.

Failing to do so can result in some major fines. Not only will you have to pay these fines, but you will end up having to re-install your roofing as well.

Pros And Cons To Putting A Metal Roof Over Shingles

As you contemplate whether or not you should put a metal roof over your shingles, consider weighing both sides. There are reasons it is a great idea. There are also some reasons you might want to think twice, or at least gather more information before moving forward. Below we have listed the pros and cons of putting a new metal roof over shingles.

Pros To Installing Metal Roof Over Shingles

Less Labor Intensive Than Shingles

One of the biggest perks to installing a metal roof over your shingles is the fact that it greatly cuts down on your labor and potential labor costs. If you need a new roof and decide metal is the way to go, then you have two choices — either completely replace the roof, or try to install the metal roof on top of the one you have.

Clearly, the first choice is less appealing because it involves a lot of manual labor. Not just any labor either. Removing shingles from your roof is a job best left to a professional.

If you were to add a new shingle roof, it would take all sorts of time, energy and resources, especially compared to metal roofing. It is also difficult and dangerous work. After all, you shouldn’t be working on top of a roof unless you have all the protective gear a professional has.

Cheaper Than Replacing Your Roof

In addition to being less labor intensive, it can also save you money. The cost of ripping a roof apart, installing all new insulation and its layers can rack up. The materials, labor and time all start costing more and more money.

If you can just install a metal roof over the existing roofing, you save most of that money, and end up with the same final product.

Can Reduce Energy Costs

It is also important to think about the benefits of metal roofs in general. One great perk to a metal roof is the fact that it can be great at insulating the home. Many people think that metal roofs will cook your house and make it very hot. In reality, metal roofs are fantastic at insulating your home. They are energy and money savers in that regard.

Visually Appealing

If when you picture a metal roof you are thinking of a tin roof in a shanty town, you need to expand your mind. Metal roofs have come a long way. In fact, some metal roofs look very sleek and stylish and you can choose between many different painted metal roofs these days.

Others are designed in patterns that mimic other types of roof, like clay tile roofs for example. So, if your shingle roof is looking shabby and outdated, a metal roof can really give your home a face lift.

Even if your shingle roof isn’t ugly, it might just not match your aesthetic. If you want a more modern look or minimalist color scheme, adding a metal roof over your shingles can go a long way at transforming your home’s look.

Adds Longevity To The Lifespan Of Your Roof

Another major perk to adding a new metal roof on top of your shingle roof is the fact that it adds significant longevity to your roof. Metal roofs are incredibly durable and long lasting. In fact, that is one of the biggest reasons people opt for metal roofing over other roof types.

Where some roofs only last 10 to a maximum of 20 years, metal roofs last anywhere from 40 to 70 years. That means if it is installed over your existing roof properly, it may last you for the rest of your life. That is certainly a perk for your bank account.

Cons To Installing A Metal Roof Over Shingles

Not Always Permitted

One obviously potential drawback to installing a metal roof over your shingles is the fact that it might not be allowed where you live. There are some locations that do not allow this type of roof installation. There are several reasons why building codes might forbid this type of installation.

Regardless of the reasoning, you need to respect your local building codes. If you build a metal roof and it is against code, you can incur a major fine. Worst of all, the municipality might even force you to disassemble the roof and do the work to code. That could be quite a hefty bill when all is considered.

The Added Weight Might Put Stress On Your Home

Another downside to stacking one roof on top of another roof is the weight. Metal roofs are not nearly as heavy as shingle or slate roofs, but they still carry plenty of weight. After all, metal is not a material you associate with being very light.

Since you will only be adding weight, not subtracting any, you need to make sure that your roof and the structure in general can withstand the added weight. Also factor in whether or not you get heavy snowfall, or other instances when there might be even more weight on top of your roof. In some cases, it might not be a good idea to add this additional weight.

Could Void Your Roof’s Warranty

Another reason you might not want to install a metal roof right on top of a shingled roof is due to your warranty. Your existing roof and the metal roof might come with a long-lasting warranty. This is a great thing to have. It acts as an extra bit of assurance that your roof will be in great condition for years to come.

Unfortunately, your warranty might not allow for this kind of installation. Some warranties are void if a roof is installed over another roof. Make sure you check your warranty before you proceed.

Might Trap Moisture

Metal roofs are durable and great at keeping water out. Unfortunately, that means they also do a good job at locking moisture in. If for some reason your current roof has a moisture problem, the metal roof might lock all that moisture in. While in most cases this insulation is a good thing, with moisture it can cause damage. This moisture can lead to damage in the roof like mold and rot.

Problems With Your Old Roof Might Get Worse

If you are looking to install a metal roof over your shingles because the roof is leaking or there are other issues, think again. You should never install a metal roof over a roof that is having major issues. Mold and rot, for example, will only get worse over time.

If there was any sagging, missing shingles or an unidentified leak, you should also not move forward. These are all warning signs of potentially bigger issues. You need to resolve these issues before you add the new metal roof.

Final Thoughts On Putting A Metal Roof Over Shingles

You might wonder if you can install a new metal roof over your existing shingles. The answer is usually yes, but not always. Check your building codes, as there may be rules that prohibit this type of project.

You should also never install a new metal roof over a roof with mold, rot or leaking issues. These problems will only continue to grow. Also make sure that this additional roof does not void any current warranty on your home. Lastly, make sure the roof can withstand this added weight before starting the installation.

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Tom Gaffey
Tom Gaffey

Tom Gaffey is an expert writer who currently resides in Washington D.C. Tom has a passion for real estate and home improvement writing, as well as travel and lifestyle writing. He lived the last twelve years in Hawaii where he worked closely with luxury resorts and event planners, mastering his knowledge of aesthetics and luxury products. This is where he found his passion for home improvement and a keen interest in DIY projects. Currently, Tom resides in Washington D.C, and also working on his debut fiction novel.

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