Can You Put a Metal Roof Over Shingles?

Installing a metal roof over existing shingles, sometimes called a “roof-over,” is an alternative to roof replacement that’s become more common in recent years, but is it a good idea? It depends. For some homes, this type of roof installation can save a lot in roofing costs and help your home be more energy efficient, but it’s not advised in all cases. Our guide will explore the pros and cons of installing a metal roof over shingles to help you plan your roofing project.

How Are Metal Roofs Installed?

If you’re deciding between a metal roof and shingles, it’s important to understand the installation process. Metal roofs can either be installed after removing the existing roofing material or directly over the existing roof. Removing the existing roofing, also called a tear-off, is the most common way to install a metal roof, but installing a new roof over the current roof—a roof-over—is becoming a popular option.

Whether you’re installing a standing seam or a screw down metal roof, you may have the choice between a tear-off and a roof-over.

Over Existing Shingles

When installing a metal roof over existing shingles, a roofer will inspect the current roof, make any necessary repairs, and confirm that the roof is in good shape and can handle the additional weight of the new roof. They’ll then install an underlayment layer, use furring strips between the metal and shingles, or use special fasteners to create space for airflow between the old shingles and new roofing. Metal panels or shingles are affixed to the current roof, allowing for proper ventilation and room for the old roof to expand and contract without damaging the new roof.

Tear-Off

With a tear-off, the roofer will remove all existing roofing materials down to the decking, measure for a metal roof, determine how much overhang the metal roof should have, and install the new roof. A tear-off is a total roof replacement ideal for homes with older roofs, extensively damaged shingles or decking, or roof weight limitations. Tear-off installations take longer than roof-overs and require removal and disposal of old roofing material, but allow roofers to assess and repair any underlying damage before installation.

Pros of Installing a Metal Roof Over Shingles

Installing a metal roof over shingles has a number of benefits, especially for budget-conscious homeowners. Pros include:

• Lower installation costs

• Shorter installation time

• Additional insulating properties

• Added energy efficiency

Cons of Installing a Metal Roof Over Shingles

If you’re deciding if a roof-over is right for your home, consider the following drawbacks as well:

• May be prohibited by local building codes

• Adds significant weight to roof structure

• May hide damaged or deteriorating roofing materials

• Can allow for moisture damage if not properly ventilated

DIY vs. Hiring a Pro to Install a Metal Roof Over Shingles

Roofing projects can be dangerous, and installing a new roof is a project you want to be sure is done safely and correctly. Hire a roofer with experience installing metal roofs over shingles—they can assess the current state of your roof and advise you if a roof-over is an option. In some cases, local building codes or homeowners insurance may require that a licensed professional perform all roof installation work.

A local metal roof installer will ensure your new roof is structurally sound, properly ventilated, securely installed, and meets all local building codes. A new metal roof can cost between $5,700 and $17,700 on average, so it’s important that your new investment is installed correctly.