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The short answer: Yes you can.
But it’s not as simple as installing another layer on top of your shingle roof.
There are still factors, such as local building codes, your roof’s weight, structure, and how much you’re willing to spend.
Don’t worry!
We’ll explain everything about installing a metal roof over shingles in this article. Let’s get started!
The First Step to Install Metal Roofing Over Shingles
So you already know you can install metal roofing over a shingle roof. But with an existing roof system in place, it’s worth diving into a little more detail before making a decision.
The next question is, “Do you have to tear off your shingle roof?”
Not necessarily.
Tearing off a shingle roof will only lead to double the costs in labor and installation.
What matters is to check with your local building code whether your local building department will allow the installation of metal roofing over shingles.
Your building department might only allow you to re-roof over one layer of shingles on your existing roof while some allow you to re-roof over two layers of shingles.
So, What Next?
Typically, a standing seam metal roof panel system is recommended, but it always helps to check with your local department if there are additional requirements.
That being said, let’s dive into other factors to consider before you install a metal roof over a shingle roof.
Factors to Consider Before Installing a New Metal Roof Over Asphalt Shingles
We’ll go over 4 crucial factors to consider before you perform a metal roofing installation over your shingle roof.
Inspect Your Roof Deck
Your roofing system plays an important role during the installation: stability.
A weak foundation will only lead to poor longevity – you’re practically burning cash this way.
So what should you look out for?
Primarily the house trusses and any signs of sagging in your roof decking are key areas to watch out for.
If you notice these during a roof inspection, you should have these repaired before installing a new metal roof.
Check for Any Signs of Water Leaks
What’s the point of installing metal roofing to improve your roof’s condition if there are existing leaks and holes?
You don’t install good over bad. That would only lead to a disaster or worse, your roof structure falling apart.
Additionally, if you find any signs of rotting, make sure to have these fixed.
Choose a Quality Roofing Company
Among other things, many might think a cheaper roofing quote will help save on costs.
This may be a good idea in some cases. After all,high labor costs, expensive roofing material/s, and a hefty overall cost are a few of the many worries most homeowners face.
But remember: the purpose of performing a re-roof or installing a new roof is a long-term investment meant to protect you and your family from strong winds, hail, rain, and the occasional afternoon thunderstorms.
Don't Forget About Building Codes
Building codes go far beyond simply abiding by the law.
The primary objective of building codes is to ensure safety when installing a new roof.
If you install too many layers of roofing material, this could cause the truss or deck to collapse from the heavy weight.
This is one of the many reasons why certain states or counties will advise the removal of roofing materials before installing layers of roofing materials.
Whether your decking structure is OSB or plywood, one should still verify the building code to ensure the longevity and stability of the roof.
How to Install a Metal Roof Over Shingles
There are 2 installation methods when installing a metal roof over a shingle roof.
The first installation method involves using new underlayment over the existing roof. The underlayment serves 2 benefits:
- Protects your metal roof from water leaks.
- Acts as a buffer between the metal roof and shingles. Without a buffer, the shingle granules can wear out against the back of metal roofing panels.
The second method involves using purlins or battens for installing metal roofing on top of an asphalt shingle roof.
This method also depends on how a metal roofing manufacturer designs the metal roofing panels.
The second method follows a process where the purlins are screwed to the roof deck followed by the metal roofing panels being installed on the purlins.
A benefit of this method is it gives a clean, flat surface to make it easier when installing the metal panels without any shingle irregularities and grooves.
Before You Install
Use Screws Instead of Nails
It’s best to use screws instead of nails since screws fasten the metal roofing in place better.
This also ensures fewer holes in your metal roof and overall, better protection and security from rain, hail, and strong winds.
Don't Overlook the Warranty
A warranty that will last you 40 or 50 years sounds appealing, but at the same time, it might be difficult to track your roofing contractor 40 years later.
As a result, make sure you choose the best product you can early on to extend the stability of your metal roof.
Pay Attention to the Trim
All of the edges in your roof must be wrapped in flashing to provide better curb appeal for your home and above all, provide better resistance against any weathering element.
Ensure Safety Above All
Always follow safety protocols when installing metal roofing for your home. This applies to all types of roofs including asphalt shingle roofing.
Wearing gloves, protective gear, and ensuring the working conditions are stable (no strong winds) are vital to a successful install.
Should You Choose Metal Roofing Over Asphalt Roofing?
If you have an old roof and have plans of re-roofing or installing a new one, metal roofs offer a huge advantage for your home long-term.
Here are a few benefits worth mentioning:
- Metal roofs can withstand strong winds much better than asphalt roofs, meaning it’s less likely for a metal roof to tear off.
- Metal roofs, when properly installed & maintained, can last up to 50 years .1k
- Due to the durability of metal roofs, it requires less maintenance than an asphalt type.
- Metal roofs reflect and block heat instead of absorbing it. Since it is able to reflect heat, you can save on cooling costs in the summer.
- Metal roofs hold up better than an asphalt-type roof against harsh weather conditions and intense heat.
Overall, choosing metal roofs for your home will give you a higher value in return, protect you from intense heat, and help you save on any associated cost/s in the long run.
Although metal roofing is a top-notch choice for your home, it’s also quite expensive and not everyone will have the budget for it.
But think of it this way: investing in top-grade or a good quality metal roof will most likely lead to never needing to purchase another roof again.
Finally, remember that before you install your new metal roof, make sure the plywood structure under your roof is stable enough to handle a new metal roof, not to mention the building code.
We hope this article was able to give you the best answer to installing new metal roofing over shingles!
