Asphalt shingles are by far the most common type of roofing across America. They’re easy to install, affordable, and get the job done decently—yet metal roofing is far superior in durability and longevity.
So why don’t more Americans opt for metal roofing? Many believe they must rip out their asphalt shingles in order to transition to a metal roof, which could double the cost of the whole ordeal. Since metal roofing is already more expensive than shingles, many people shy away from the idea.
But we have a word of good news. It’s possible to install a metal roof over shingles, reducing costs, while giving all the benefits of a high-quality metal roof. Check out our guide to learn more about how to install metal roofing over shingles.
Benefits of Installing a Metal Roof Over Shingles
Before we get into the steps for installing a metal roof over shingles, let’s dive more into the pros and cons. Installing a roof is a big decision, and you want to make sure this option is right for your needs. After all, once your metal roof is installed, it will be there for decades to come. Here are some of the benefits of installing a metal roof over shingles.
While most roofing contractors discourage homeowners from installing a new asphalt roof over an old one, the circumstances are more favorable when installing metal over asphalt. Metal roofing is very lightweight, making it easy to install over the top of shingles.
2. Save Money
Of course, one of the most appealing aspects of installing a metal roof over an existing shingle roof is the fact that it will save you a lot of money. Hiring a contractor to remove a shingle roof means paying for hours and hours of labor, which significantly bumps up the price. And though metal roofing costs more than asphalt shingles upfront, it is usually more cost-effective in the long run, since it lasts decades longer than an asphalt roof.
3. Avoid the Mess
Removing an asphalt shingle roof isn’t just costly—it’s messy, too. Homeowners who want to avoid turning their property into a busy construction zone for days on end should consider the faster, cleaner route of installing the new roofing over the old one.
As we mentioned earlier, metal roofs are known for their impressive longevity. While an asphalt shingle roof usually needs to be replaced every 20 years (or even more often), a metal roof should last at least 50 years. In fact, some metal roofs are known to last over 60 years.
Metal roofs have been increasing in popularity for years, mainly for their extreme durability compared to asphalt shingles. They’re resistant to fire damage, rotting, and damage from termites and other insects. Snow will slide off the roof more quickly since the roof conducts heat efficiently. They’re even more energy-efficient than asphalt roofing.
Drawbacks of Installing a Metal Roof Over Shingles
After learning all the benefits of metal roofs, you may be ready to rush off and get yours installed right away. This is a no-brainer, right? And many of the supposed drawbacks about metal roofs aren’t actually true. For example, metal roofs aren’t any more likely than an asphalt roof to attract lightning. But there are a few drawbacks to consider, including the following.
1. Building Codes
A contractor can only install a metal roof over asphalt shingles if the building code allows. And unfortunately, some codes simply do not allow it. It’s important to check with local building codes before moving forward, because they may require full removal of the old roof before installation.
2. Hail Damage
Although metal roofing is more durable than asphalt shingles, these roofs can be damaged by some types of weather, like extreme hail. Larger hailstones may dent roofs made from aluminum and copper, so it’s important to choose a homeowner’s insurance plan that will cover this type of storm damage.
3. Professional Installation Required
Some homeowners choose to install asphalt shingle roofing themselves. But when it comes to installing a metal roof, this is a job best left to the professionals. Metal roofing installation and repair requires a unique skill set, so we advise homeowners to find a company experienced with this type of roofing.
What Kind of Metal Roof Can Be Used?
Many types of metal roofing can be installed over asphalt shingles. Each option has its own set of benefits. Here are a few of the most common options:
- Copper: Long-lasting, soft and quiet, low melting point.
- Aluminum: Durable, resistant to damage from saltwater.
- Zinc: Incredibly durable and long-lasting, resists corrosion, low melting point.
- Steel: One of the most durable and long-lasting options. Comes in variations of galvanized, Galvalume, and weathering.
Steps to Installing a Metal Roof Over Shingles
Though there are many ways to install a metal roof over shingles, we recommend this installation method, which provides the most durability over time.
1. Inspect Plywood
It’s important to first inspect the plywood under the asphalt shingles to make sure it is in good condition. If there is any rotting or corrosion, it’s important to resolve that issue before installing a new roof. If it is in good shape, then it’s okay to move forward.
2. Install Synthetic Underlayment
Installing underlayment will help to keep the asphalt shingle granules from running up against the new metal roof, which could cause damage over time. Though most underlayment is made from a felt-type material, we recommend using synthetic underlayment, which will not tear when the metal roof expands and contracts.
3. Add Insulation
Adding E-foil insulation to the top of the underlayment will provide a protective surface between the old asphalt roof and the metal roof. This layer can also increase energy efficiency by reflecting heat away from the roof in the summer.
4. Install Corrugated Metal Panels
Now it’s time for the final step: installing the metal roof. E-foil insulation is best paired with corrugated metal, which allows air to flow and creates a natural venting process.
Shop Metal Shingles Today
Ready to install a metal roof over shingles? Shop for high-quality metal shingles today at 1st Coast Metal Roofing Supply. Whether you’re a contractor or a homeowner, we have all the high-quality materials you need to properly install a metal roof over shingles. Check out our shingles, metal roof panels, and metal roof tools and accessories now.