One thing in life is for certain – trends are ever-changing. When something becomes popular, and everyone has to have it, a new fad comes along, leaving the old one in the dust.
If you wait long enough, some trends come back in style. Wide-leg pants. Scrunchies. Aviators, bomber jackets, and mustaches (thank you, Top Gun). To name a few comebacks that we’ve witnessed in the last year.
But not all trends are fashion-related. The post-frame construction industry is no exception.
More stick-built homes are moving from asphalt shingles to metal roofing. This number has reached 15 percent since 2020. (Source: McElroy Metal)
Not only do metal panels look sleek on a residential dwelling or pole barn, but they’re durable and energy-efficient. Longevity and cost savings (ka-ching!) are two appealing factors to homeowners.
This article outlines how to transition from a shingle roof to a metal roof in four steps. But first, you must decide if you’ll keep or remove the asphalt shingles.
Can You Install Metal Roofing Over Shingles?
In most cases, you can install metal panels over a shingle roof. However, we highly recommend checking with your local building and zoning department to confirm that they allow metal-over-shingle installations.
Below, we detail the key benefits you’ll enjoy if you install metal roofing over asphalt shingles:
1) Reduced Installation Time
Placing metal panels on top of a shingle roof will reduce the installation time. Construction crews don’t have to worry about removing the existing building material. Instead, they can focus on laying furring strips and securing the new metal roofing.
2) Significant Cost Savings
Because a metal roof can be easily retrofitted over your old shingles, you’ll eliminate tear-off and extra labor costs.
Since you’re not discarding the old shingles, you don’t have to rent a dumpster (reducing landfill waste). Per Recycle Nation, 11 million tons of asphalt shingle waste is generated in the U.S. each year. Who wouldn’t like to save money and the planet?
3) Additional Roof Insulation
Next, the dead air space between the metal panels and a shingle roof can act as insulation. This trapped air is an excellent insulator. It reduces conduction and convection (i.e., heat loss).
However, dead air space shouldn’t be your only source of roof insulation. For more information about popular insulating materials, we recommend downloading our FREE “Ultimate Guide to Pole Barn Insulation.”
What Issues May Arise If You Install Metal Roofing Over Shingles?
If you choose to install metal panels over a shingle roof, there are potential issues worth considering and looking into before starting your renovation project:
1) Unanticipated Structural Loads
Let’s go back to when your house was first designed, shall we? The stick-built construction company designed your home to withstand anticipated structural loads (e.g., shingles as the roofing material).
Fast forward X years later, you want to install a metal roof. While this building material is relatively lightweight, it will add approximately 2 pounds per square foot (psf) to the existing roof structure. If the trusses weren’t designed to support this extra weight, you might encounter long-term issues like sagging or breaking.
Editor's Note: Your post-frame builder must inspect the structural integrity of your shingle roof before installing metal panels.
2) Undesirable Oil Canning
According to the Metal Construction Association, oil canning is defined as the “visible waviness in the flat areas of metal roofing.” Technically speaking, oil canning is referred to as “elastic buckling” or “stress wrinkling.”
This visual phenomenon can occur with any metal used in construction: aluminum, copper, steel, or zinc. In other words, oil canning is an essential characteristic of metal roofing.
While hard to define to an untrained eye, oil canning can occur for several reasons:
- Stress during the production process (i.e., camber, full center, and wavy edge)
- Stress during the roll forming and coil slitting (cutting)
- Darker paint colors (show more defects than lighter hues)
- Improper usage and handling by inexperienced construction crews
- Restricted expansion and contraction during thermal movement
The best way to reduce oil canning is to select a skilled post-frame builder who knows how to install metal panels properly.
How Does FBi Buildings Transition from Shingles to Metal Roofing?
Depending on the structure being re-roofed, our Repair & Renovation Specialists take the following steps:
1) Assess the Situation & Take Measurements
Once you’ve contacted our Repair & Renovation Specialists about installing metal roofing, they’ll send an experienced construction crew to examine the shingle roof.
Then, our field employees will take the necessary measurements to ensure the proper lengths for the following building features: gutters, metal panels, ridge caps, and trim.
After the measurements are confirmed, the building materials will be ordered, cut, and ready to be installed over your shingle roof.
2) Prep the Shingles for Metal Roofing
The first day on the job site involves prepping your shingles for metal panels.
If you want to remove the asphalt shingles, our construction crews will discard the existing roofing material and inspect the underlayment for damage.
Roof underlayment is the layer beneath your roofing system that serves as a vapor barrier and prevents moisture damage. The three common underlayments are felt, self-adhering membrane, and synthetic sheet.
If you plan on keeping the existing shingles to save time and money, our field employees can move on to the next step.
3) Secure the Metal Panels to the Roofing System
Once the base of the roof is ready, our construction crews will secure the metal panels to furring strips, oriented strand board (OSB), or plywood.
If our construction crews retrofit a metal roof over old shingles, they’ll lay down furring in 1x3 or 2x4 strips. These thin pieces of wood are used to level or raise the surface of another building material.
Then, our field employees can screw the metal panels into the furring strips, through the asphalt shingles, and into the underlying OSB or plywood.
If the shingles were removed, our construction crews would attach the metal panels to the OSB or plywood directly (furring strips aren’t necessary in this case).
4) Add Final Touches to the Metal Roof
Lastly, our field employees will add the final touches to the metal roof to conclude this renovation project. This step consists of installing gutters, rake trims, and ridge caps. Gutters should be re-installed after the metal roof is properly flashed.
Will You Transition from Shingles to Metal Roofing?
Now that you know more about metal roof installation, will you ditch the shingles on your stick-built home? This trend in post-frame construction is long-lasting, and more homeowners are enjoying the energy savings that come with it.
Whenever you’re ready to make the switch, our Repair & Renovation Specialists will help you get started by answering questions and providing a FREE metal roofing quote. For more helpful information, we recommend downloading the Ultimate Guide to Pole Barn Repairs & Renovations.
Do you have more questions about metal roofing not covered in this article? If you need help designing and planning, please contact FBi Buildings at 800.552.2981 or click here to email us. If you're ready to get a price, click here to request a quote, and a member of our Customer Engagement Team will help you determine the next steps of your project.