How To Install Metal Roofing Over Asphalt Shingles?

Metal roofing is an increasingly popular choice for homeowners due to its durability, energy efficiency, and aesthetic appeal. If you have an existing asphalt shingle roof, you may wonder if installing a metal roof over the shingles is possible. Yes, it is possible, but it requires careful planning and execution. 

This article will discuss the steps involved in installing metal roofing over asphalt shingles.

Step 1: Evaluate the Condition of the Existing Roof

Before installing a metal roof over asphalt shingles, evaluating the existing roof’s condition is essential. Removing the shingles before installing the metal roofing is best if the shingles are severely damaged, curled, or missing. If the shingles are in good condition, you can proceed with the installation.

Step 2: Prepare the Roof Surface

Once you’ve evaluated the existing roof’s condition, it’s time to prepare the surface for the metal roofing. The roof should be cleaned, and any debris, such as leaves and branches, should be removed. 

On top of that, any loose or damaged shingles should be secured or replaced. Finally, the roof should be checked for protrusions or irregularities that could interfere with installing a metal roof.

Step 3: Install Furring Strips

To ensure a smooth and even surface for the metal roofing, it’s recommended to install furring strips over the existing shingles. Furring strips are typically made of wood and are installed horizontally over the roof. 

The strips provide a solid base for the metal roofing and help to prevent moisture buildup between the metal and asphalt layers.

Step 4: Install the Metal Roofing

Once the furring strips are installed, it’s time to install the metal roofing. The roofing panels should be installed starting at the eave and working upwards towards the ridge. The panels should be secured to the furring strips using screws and neoprene washers. 

It’s essential to ensure that the panels are aligned and that the screws are tightened enough to hold the panels securely in place but not so tight that they damage the metal.

Step 5: Finish the Edges and Seams

Do you want to ensure a watertight seal? The edges and seams of the metal roofing should be finished using appropriate flashing and sealant. This includes installing drip edges along the eaves and rakes and ridge caps at the roof’s peak. 

Flashing should also be installed around protrusions, such as chimneys or vents, and sealed with a high-quality silicone sealant.

Step 6: Inspect and Maintain the Roof

Once the metal roofing is installed, it’s essential to inspect it regularly and perform any necessary maintenance. This includes checking for damage or corrosion, cleaning the roof to remove debris and prevent algae growth, and ensuring the flashing and sealant are intact and functioning correctly. 

Proper maintenance can help extend the lifespan of your metal roofing and prevent costly repairs.

How Long Does It Take to Install Metal Roofing Over Asphalt Shingles?

The amount of time it takes to install metal roofing over asphalt shingles can depend on several factors, including the roof’s size and complexity, the roofing contractor’s experience, and any unforeseen issues that may arise during the installation process. However, completing the installation process can generally take a few days to a week.

The first step in the installation process is to inspect the existing roof to ensure it’s suitable for metal roofing installation. Any issues, such as leaks or damage, must be addressed before the installation can begin.

Next, the old shingles must be removed from the roof to create a clean and smooth surface for the metal roofing panels to be installed. Once the old shingles are removed, any damaged or rotted decking must be replaced or repaired.

After the roof surface is prepared, the metal roofing panels can be installed. This involves measuring and cutting the panels to fit the roof, then securing them using screws or other fasteners. Flashing and trim must also be installed around the roof’s edges to ensure a watertight seal.

Finally, the roofing contractor will conduct a final inspection of the roof to ensure that everything has been installed correctly and that there are no leaks or other issues. The entire installation process can take anywhere from a few days to a week, depending on the size and complexity of the roof and the weather conditions.


Can I install metal roofing over multiple layers of shingles?

No, installing metal roofing over multiple layers of shingles is not recommended, as it can compromise the roof’s structural integrity. It’s best to remove all the layers of shingles before installing the metal roofing.

How much does it cost to install metal roofing over asphalt shingles?

The cost of installing metal roofing over asphalt shingles can vary depending on factors such as the size of the roof, the type of metal roofing, and the labor costs in your area. It can cost anywhere from $6 to $12 per square foot.

Can I install metal roofing over a flat roof?

Yes, installing metal roofing over a flat roof is possible. Still, additional steps may be necessary to ensure proper drainage and prevent moisture buildup. It’s best to consult with a roofing contractor with experience with flat roof installations.

What are the benefits of installing metal roofing over asphalt shingles?

  • Durability: Metal roofing is much more durable than asphalt shingles and can withstand extreme weather conditions like high winds, heavy rain, and hail. It’s also resistant to fire and pests, making it an excellent long-term investment.
  • Energy efficiency: Metal roofing can help to reduce energy costs by reflecting heat and keeping the interior of the building cooler in the summer. This can also help to extend the lifespan of the roofing system.
  • Longer lifespan: Metal roofing can last up to 50 years or more, significantly longer than traditional asphalt shingles, typically around 20 years. This means fewer replacements and less maintenance over time.
  • Improved aesthetics: Metal roofing comes in various colors and styles, which can add to the overall aesthetic appeal of the building. It can also increase property value and curb appeal.
  • Environmentally friendly: Metal roofing is a sustainable choice because it’s recyclable and can be made from recycled materials. This makes it an eco-friendly option for homeowners and building owners looking to reduce their environmental impact.


Installing metal roofing over asphalt shingles can be a great way to upgrade the look and durability of your roof without the expense and hassle of a complete tear-off and replacement. 

However, it’s essential to ensure that the existing roof is in good condition and that the installation is done correctly to avoid any issues down the line. 

By following these steps and working with an experienced roofing contractor, you can enjoy the benefits of a beautiful, long-lasting metal roof.