One question that comes up a lot when homeowners research materials for their roof replacement is: “Can you put a metal roof over shingles?”
Deciding to put a metal roof on top of the existing shingles involves a number of elements that should be carefully considered, but in general, the answer is yes.
To assist you in making an informed decision for your house, this thorough blog post will examine the benefits and drawbacks of this strategy and help you understand if you should put a metal roof over shingles.
The Main Question: Can You Put A Metal Roof Over Asphalt Shingles?
While not recommended in most cases, yes, you can usually install a metal roof over existing shingles. This choice, called roof overlay, saves on labor and disposal costs as the old roof stays in place. You can typically place metal panels over one layer of shingles. However, if there are two or more layers, the shingles must be removed first.
Before you choose this roofing method, check your local building codes, as some areas limit the number of roof layers allowed. Generally, you can’t have more than two layers on one structure. If your home already has two layers of shingles, you’ll need to remove them to ensure your new metal roof is installed properly and lasts longer.
Pros of Installing a Metal Roof Over Shingles
A metal roof is a durable and stylish choice, but can it go over existing shingles? To help you make the right choice, let’s dive in to understand the pros of metal roof overlay:
1. Cost Savings
One of the main benefits of installing a metal roof over shingles is cost savings. Skipping the labor-intensive process of tearing off the old roof can save you 15-20% of the total project cost by avoiding disposal fees.
2. Time Efficiency
A roof-over installation can speed up your project significantly. Without the need to remove old shingles, the installation process is much faster, allowing you to enjoy your new roof sooner.
Cons of Installing a Metal Roof Over Shingles
While convenient, putting a metal roof over shingles has some downsides to be aware of:
1. Hidden Problems
Keeping old shingles may hide issues like rot or leaks. If not fixed early, these problems can lead to costly repairs later.
2. Weight Concerns
Metal roofs are heavier than asphalt shingles. Adding extra weight to an already stressed structure could lead to problems later, especially if the roof deck is weakened.
3. Trapped Moisture
Installing metal over shingles can create a space that traps moisture, leading to premature deterioration of both the shingles and the new metal roof, potentially causing leaks.
4. Warranty Issues
Many manufacturers might void warranties if a metal roof is installed over shingles. Homeowners should check warranty conditions before proceeding.
5. Aesthetic Concerns
The bumps from old shingles can create an uneven surface for the new metal roof. This may lead to visual imperfections.
Key Considerations for Installing a Metal Roof Over Shingles
If you’re set on installing a metal roof over shingles, there are a few key considerations to keep in mind:
Weight
When adding a metal roof over shingles, weight is an important consideration. Metal roofs typically weigh 1 to 1.5 pounds per square foot, so it’s essential to make sure your structure can handle the weight of both layers, especially in snowy regions. Local building codes may set weight limits, so it’s wise to check these requirements.
How Much Weight Does A Metal Roof Add?
Depending on the style, a metal roof typically adds 1 to 3 pounds per square foot. Steel weighs roughly 1.5 pounds per square foot, whereas aluminum weighs about 1 pound. Compared to heavier materials like concrete tiles, metal roofs are easier on your home’s structure because of their lightweight nature.
Metal roofs are a robust and effective choice for homeowners because they frequently don’t require additional support. However, the existing weight of the shingles plus the new metal roof can lead to stress on the rafters and roof deck.
Condition of Existing Roof
The condition of the shingle roof also plays a role. Building codes usually allow up to two shingle layers, so if there are already two, you may need to remove them. The shingles should be flat and in good shape to provide a stable base. Proper drainage and ventilation are also necessary to prevent issues like water pooling or moisture buildup. If the existing roof is not in pristine condition, removing the shingles is usually recommended to ensure a long-lasting new roof.
Climate
Your local climate affects how a metal roof is installed. Areas with strong winds, heavy snowfall, or extreme temperatures require extra strength and durability. Snow and ice add weight, and temperature changes can cause materials to expand and contract. Moisture and humidity also need attention to avoid condensation or other long-term issues. In regions with these conditions, completely tearing off the old roof can provide a flat, durable base for the new metal panels.
Alternatives to Consider
When deciding whether to install a metal roof over existing shingles, it’s important to know that most roofing contractors do not recommend it. As alternatives, you can consider two main options: a partial tear-off or a complete tear-off, each with its own benefits and drawbacks.
Partial Tear-off
A partial tear-off removes only the damaged areas of your roof. This option is helpful if most of your roof is still in good shape but has specific issues, like leaks or missing shingles. It’s budget-friendly and less disruptive since only problem areas are fixed. However, there’s a risk of hidden damage that could cause issues later, and the roof’s surface may not be completely even for metal installation.
Complete Tear-off
A complete tear-off takes off all the shingles, giving you a fresh start. It’s a good choice if your roof has a lot of damage or if you’re planning to stay in your home for a long time. This option allows for a full inspection of the deck, letting you fix any hidden problems like rot. Although this is more costly and takes more time, it provides a smooth, clean surface for the new metal roof, which can help it last longer.
Conclusion
Installing a metal roof over shingles can be tempting for the time and cost savings, but it’s essential to consider the possible risks. To make the best choice for your home, consult a qualified roofing professional. They can evaluate your roof’s condition, explain your options, and give you a detailed estimate for both tear-off and overlay installations.
Are you in need of a dependable roofing company in Minnesota? Clear Cut Xteriors is here to help! Whether you’re interested in traditional shingle roof services or long-lasting metal roofing services, our team of roofers will help you find the best match for your home and budget. With the best quality materials and skilled installation, repair, and replacement services, we will always ensure lasting results. Click here for an instant roof quote, and for more information, give us a call at (651) 340-3410!
