Everyone at some point has heard of the saying “out with the old, in with the new.” But when it comes to roofing, a new roofing material does not necessarily mean you have to get rid of the old one. A home that removed asphalt shingles and installed a standing seam metal roof If you’re getting ready to make a big roofing change from asphalt shingles to metal, you’ll have to first make a decision on what to do with your old shingle roof. One option is that your old shingles can be removed prior to the new metal roof being installed, but that is not your only choice. It may come as a surprise that a metal roof can actually be installed over your existing shingle roof. But just because something can be done, does that mean you should do it? At Western States Metal Roofing, we have over two decades of experience with customers upgrading from asphalt shingles to a metal roof that are faced with this exact decision. We believe that this choice should be made on a case by case basis. It depends on different factors and every roof is going to be different from the next. In this article, you’ll learn more about re-roofing (installing your new roof over an existing roof). We will also go over 4 factors to consider when deciding if you should remove your asphalt shingle roof before you install a metal roof.
Everyone at some point has heard of the saying “out with the old, in with the new.” But when it comes to roofing, a new roofing material does not necessarily mean you have to get rid of the old one.
A home that removed asphalt shingles and installed a standing seam metal roof
If you’re getting ready to make a big roofing change from asphalt shingles to metal, you’ll have to first make a decision on what to do with your old shingle roof. One option is that your old shingles can be removed prior to the new metal roof being installed, but that is not your only choice. It may come as a surprise that a metal roof can actually be installed over your existing shingle roof.
But just because something can be done, does that mean you should do it?
At Western States Metal Roofing, we have over two decades of experience with customers upgrading from asphalt shingles to a metal roof that are faced with this exact decision. We believe that this choice should be made on a case by case basis. It depends on different factors and every roof is going to be different from the next.
In this article, you’ll learn more about re-roofing (installing your new roof over an existing roof). We will also go over 4 factors to consider when deciding if you should remove your asphalt shingle roof before you install a metal roof.
Installing Metal Roof Over Shingles Pros And Cons
There are many advantages to putting your new roof over the old roof, which is a process that can be known as either overlaying, or re-roofing.
Pros Of Putting A Metal Roof Over Shingles
- You’ll save on labor costs. Not removing the asphalt roof first results in less work for the contractor.
- Added insulation protection to your home by having extra roofing layers.
- Faster installation as less labor is required.
- Eco-friendly because the old asphalt shingles will not have to be thrown away.
Metal is an easy material to use when re-roofing because it’s a lightweight material. It weighs less than one pound per square foot. A new metal roof won’t put a lot of extra stress on your home, even with your old asphalt shingle roof also still attached underneath.
Cons Of Putting A Metal Roof Over Shingles
- It Is Restricted By Some Building Code
- Problems With Shingles May Affect The New Roofing
- Moisture Can Become Trapped
- May Void Your Warranty
We go into detail on each of these issues and the questions you should consider before deciding if you should put a metal roof over your shingle roof.
1. Does The Building Code Allow For A Metal Roof To Be Placed Over Shingles?
The choice is easy when there isn’t a decision to be made. Local building code can make your decision simple if it specifies that the existing shingles have to be removed first.
It’s common to find building codes that will allow for two layers of roofing on a structure, but that is not always the case. Check your local building codes to see what is allowed in your area. Not complying with building codes can result in expensive fines.
2. Are There Problems With Your Previous Roof?
If there are problems with your old roof, putting a new roof on is not going to fix them. In fact, it will eventually make them worse.
If your previous roof weighs more than the structure of your home can adequately handle, adding the additional weight of the metal roof will cause a bigger problem. Some warning signs of problems from the weight of your roof may include buckling trusses or sagging roof decking. Prior to installing a metal roof over an existing shingle roof fix any rotten wood sheeting or rafters.
If your asphalt shingle roof has leaks, those problems need to be addressed. Parts of the roofing system may have water damage, and these issues would have to be repaired or replaced. You may have already noticed water damage issues that led you to determine you need a new roof in the first place. Ignoring these issues will lead to a shorter lifespan for your new roof and more expenses in the future.
3. Can Moisture Get Trapped Between The Metal And Asphalt Shingles?
One of the benefits of a metal roof is that it is resistant to rotting and mildew. However, this benefit is cancelled out if moisture is able to get in between the new metal roofing panels and the old asphalt shingle roof.
Moisture between these surfaces can result in mold and rotting which will ultimately lead to costly repairs.
Here are two ways to eliminate trapped water vapor:
- Ridge vents are designed to create constant air flow along the horizontal ridge of your house. They create a space for airflow that allows moisture to escape.
- Furring strips will raise the metal roofing and allow for ventilating air pockets between the metal and shingles.
Every roof is different and must be analyzed by the roofing contractor to determine what’s best for your specific roof. However, all metal roofs should have roofing underlayment regardless of whether it’s a new installation or being installed on top of an existing shingle roof. Roofing underlayment creates an added layer of protection from moisture.
To learn more about how roofing underlayment helps block moisture, we suggest reading:
Does Metal Roofing Need Underlayment? A Guide For Homeowners
To learn more about how ridge vents will increase airflow and lower energy costs, we suggest reading:
Ridge Vents For Metal Roofs. Everything You Need To Know
4. Will The Warranty On The Metal Roof Be Void If Installed Over Shingles?
The specifications of your metal roof warranty will vary depending on the manufacturer. You, or your installer, must check the metal roof warranty to make sure that you aren’t breaching the warranty terms by installing it over asphalt shingles. Doing so will leave you without any coverage on your brand new roof.
Is It OK To Put A Metal Roof Over Shingles?
Depending on the situation, it may be fine to put a metal roof on top of shingles. It’s important to take the specific factors of your roof replacement into consideration when deciding what to do about removing your old roof or not.
You should remove your old asphalt shingle roof before installing a metal roof when:
- There are signs of structural issues from the weight of your roof.
- There is leaking or other damage caused by your current roof.
- Your metal roof warranty will be void by installing over asphalt shingles.
- You have to in order to comply with local building codes.
You may decide to install a metal roofing material over old asphalt shingle roof when:
- It’s in compliance with your local building code.
- You are using roofing underlayment and vented ridge cap to prevent moisture buildup.
- You are looking to save money in the short term by saving on labor costs.
- You will still be eligible for warranty coverage.
No matter which way you decide to go, avoiding errors during installation is crucial to the longevity of your metal roof. The installation of your new metal roof requires a different set of skills than installing a shingle roof. It’s important to hire a qualified metal roofing contractor to do your installation.
Haven't decided on a color or style for your new metal roof? Download our free guide to choosing the right metal roof color!
Corrugated metal roof or standing seam? If you're not sure which type of metal roof you're interested in, watch our video below to learn the differences between these roofing systems.
Thanks to the metal's lightweight nature, you can almost always install metal roofing over existing shingles.Can you put metal roof directly on top of shingles? ›
In almost every case, the answer is yes, you can lay down a new metal roof over an existing shingle roof. This is one of the many reasons metal roofs keep growing in popularity – their installation doesn't require completely tearing off the existing roof, which is a time-consuming and expensive job.What is the best way to install a metal roof over shingles? ›
The first is to apply an approved underlayment over the old shingles. This is the fastest way to install but it doesn't provide the flattest surface for metal roofing installation. The second way is to install 1×4 purlins over the shingles. This is more expensive but will also be higher quality.Should you take shingles off before putting on a metal roof? ›
Metal roofs can be installed over your existing roof without tearing off shingles, provided local building codes allow it.Do I need underlayment for metal roof over shingles? ›
Do You Need Underlayment for Metal Roofing Over Shingles? Underlayment is not required when installing metal roofing over shingles but is a definite plus. This extra layer ensures the previous shingles are not under continued stress which could lead to an increased risk of roof damage.Can you put metal roof over shingles without furring strips? ›
It is not recommended to install metal roofing over shingles without furring strips. The thermal expansion and contraction of the metal will rub against the shingle granules and the metal will corrode from the underside. The gaps introduced by furring strips also allow air venting which can reduce moisture.Does a metal roof need to be vented? ›
A metal roof typically does not increase nor decrease the need for ventilation. Ventilation that meets code requirements is adequate for any type of roofing material, including metal.Are metal roofs loud in rain? ›
This is one of the most frequently asked questions we hear from homeowners interested in metal roofing. We'll get right to the point–no, metal roofs are not loud in the rain. Preventing sounds from hitting hard, flat surfaces is key to noise reduction.How much more expensive is a metal roof compared to shingles? ›
Shingle roofs are cheaper up front.
Metal roofs generally can run from $120 to $900 per 100 square feet (one 10-foot by 10-foot area, or a “square” of material), while asphalt shingles will be between $100 and $200 per 100 square feet.
As mentioned earlier, metal roofs do not attract lightning. In fact, a metal roof can actually make a lightning strike much less dangerous.
While there are cheaper options on the market, metal roofing offers performance, protection, and profitability. Today, a metal roof can increase a home's resale value up to 6% when compared to asphalt.Does a metal roof need a vapor barrier? ›
Metal roofs and buildings require specific insulation and vapor barrier to meet the demands of condensation and breath-ability. Depending on whether your building is sheeted or not, or if you require insulation, we have it all, including the necessary tapes for installation.Do metal roofs need ice and water shield? ›
For most roofing projects, two types of underlayment are needed, the first being an ice and water shield. This underlayment is made of either a rubberized-asphalt or butyl-based adhesive with a polyethylene carrier sheet, and it has an adhesive backing with a peel and stick feature.Are metal roofs hotter than shingles? ›
Metal Roofs Make Homes No Hotter Than Any Other Roof
Any dark colored material, including asphalt shingles, ceramic tiles, wood, etc., will absorb heat when exposed to direct sunlight for prolonged periods of time. Metal roofing is no different.
One to two shingle layers can rest safely and securely under a metal roof. Any more than two layers could reduce the stability of your roof. Many building safety codes will not allow more than two layers, so check your local areas before making an installation.Do you need underlayment on a metal roof? ›
Some might choose to skip using underlayment to save money. However, the metal roof underlayment acts as an added layer of protection. You can save money by using underlayment because it will help you avoid problems that would need to be fixed. The short answer is yes, your metal roof does need underlayment .Will a metal roof cause mold? ›
It is important to reiterate that metal roofs themselves do not cause mold in your home. It is simply a case of proper installation and insulation. When installed correctly, a metal roof will be able to protect your home for many years and will provide the perfect barrier against the elements.How do you vent a metal roof over shingles? ›
To vent the roof, holes are cut in the old roof (Detail 1) above the soffit, which pulls air through the soffit vents underneath. Cool outside air then travels under the shingles to the vented ridge (Detail 2), pulling out moisture and heat.Do metal roofs require a ridge vent? ›
A metal roof is intrinsically durable and energy-efficient, but it needs proper ventilation to live up to its expectations. If the existing roof is properly vented, then a ridge vent is in order. The roof will need to be evaluated to determine what venting is needed, if at all.How do I stop my metal roof from sweating? ›
- Use Proper Insulation. Insulation that regulates the temperature inside of a metal building helps reduce condensation. ...
- Install Vapor Barriers. ...
- Ventilate The Interior. ...
- Look Up For Condensation Troubles. ...
- Prevent Water From Seeping Below.
Most metal roofing is considered to be Assembly-Rated Class A, meaning the covering and underlying materials provide additional fire protection. This makes metal roofs one of the most fire-resistant options on the market for roofing materials.Do metal roofs need gutters? ›
Strictly speaking, metal roofs do not require gutters because metal roofs themselves are resistant to the damage gutters are designed to prevent. However, gutters do play a significant role in protecting other parts of your property.What is the lifespan of a metal roof? ›
The average metal roof will last between 40-70 years. Some materials, like copper roofing, will last even longer — with some copper roofs dating back over 100 years. There are also a number of factors that can increase the longevity of your roof, as well as decrease it.Do metal roofs leak? ›
Few Roofing Products offer the durability, strength, and performance of metal roofing. That being said metal roofs aren't indestructible and they can leak. Here are 5 common reasons even properly installed metal roofs can leak. Roofing screws are responsible for the majority of leaks on metal roofs.Do metal roofs rust? ›
With advances in paint systems, finishes, and other technologies, metal roofs will withstand oxidation and rusting for most of its lifetime. However, there can be factors that affect whether or not your roof rusts. If you have plain, bare steel for example, it will rust.Is metal roof worth the money? ›
If price is your sole consideration, again, a metal roof is not worth it. You'll pay more for a metal roof than most other material options, and the pay-off is a great-looking, high-performing roof that likely won't require repairs or replacement for upward of 50 years.How much more does a metal roof cost over asphalt shingles? ›
Metal roofs generally can run from $120 to $900 per 100 square feet (one 10-foot by 10-foot area, or a “square” of material), while asphalt shingles will be between $100 and $200 per 100 square feet. Its installation will also run you more for metal since it's a more specialized job.What do you put down under metal roofing? ›
The traditional and most common material used for roof underlayment on a steep-slope metal roof is non-perforated, asphalt-impregnated felt underlayment. There are several types of felt underlayment including both organic reinforced and inorganic reinforced.