As solar energy adoption continues to rise across the United States, rooftops are emerging as one of the most strategic assets in the transition to clean energy. For the roofing industry, this is not just a passing trend—it’s a long-term opportunity to grow alongside the solar sector, particularly in the retrofit and re-roofing market.
From a roofing perspective, the value of the rooftop has never been clearer. It serves its primary function—protecting the structure—but also offers an uncluttered, already-built platform ready to host solar photovoltaic (PV) systems without additional land or new infrastructure.
Rooftop solar is good for the environment and consumers alike. It helps reduce fossil fuel dependence, relieves stress on the electrical grid at a local level, and importantly—is a prudent investment that offsets the electrical bill for more than three decades (provided the roof lasts that long). For aging roofs, it presents a chance to upgrade the roof in tandem with a solar energy investment, delivering both immediate energy savings and a service life that far exceeds the 30-year objective stated.
The 20-year-old roof of the McIndoe Clinic, a purpose-built consultation and day surgery facility for oral and maxillofacial surgery in the Bay of Plenty region in New Zealand, was retrofitted with a trapezoidal metal roof and a 29.5-kilowatt rooftop solar array utilizing the S-5! PVKIT rail-less solar mount.
Diagram 1. Copyright S-5! Used with permission.
Diagram 2. Copyright S-5! Used with permission. For more information, videos, and webinars on solar mounting best practices on metal roofs, visit www.s-5.com.
Rooftop Solar Has Barely Scratched the Surface
Despite these advantages, rooftop solar is still in its infancy. According to Rooftop Solar on the Rise, a report by The Frontier Group and the Environment America Research & Policy Center, “America could produce the equivalent of 45% of the electricity we currently use from rooftop solar, yet, in 2022, rooftop solar provided only 1.5% of America’s electricity.”
The report also states that small-scale solar—most of which is installed on rooftops—generated only 61 terawatt-hours of electricity out of a possible 1,745 terawatt-hours based on available rooftop space. That’s just 3.5% utilization.
Much of this untapped potential lies with existing buildings, many of which are overdue for re-roofing. This positions the metal roofing community for significant growth in retrofits that replace aging roofs with solar-ready systems, enabling solar installation at the time of re-roofing.
Metal Roofing: The Ideal Platform for Retrofits + Solar
Over the past four decades, well over 2 billion square feet of metal roofing has been installed in the U.S. annually, and that number continues to grow. Metal roofs are known for their durability, longevity, and sustainability—and now they are also recognized as the most solar-compatible roofing type.
Metal roofing is a natural choice for mounting solar PV because it provides:
• An ideal mounting surface
• A long service life that outlasts the solar system itself
• Lower installation costs thanks to easier mounting methods
• Sustainability and recyclability unmatched by other roofing materials
In re-roofing scenarios, choosing a metal roof ensures that the building won’t require another re-roof halfway through the solar system’s life.
Matching Service Lives: Why Metal Makes Sense
In commercial and industrial markets, a field and laboratory study by the Metal Construction Association [https://www.metalconstruction.org] indicates that standing seam coated steel roofing systems have a service life of up to 70 years.
That greatly exceeds the average lifespan of a solar PV system, which ranges from 28 to 37 years, with a median around 32.5 years, according to a Berkeley study. This means a properly installed metal roof will outlive the solar array, avoiding costly and disruptive roof replacements during the lifetime of the solar PV system.
Most traditional roof types—like asphalt shingles or TPO—require replacement every 15 to 20 years. That’s often before the solar system reaches even the halfway point of its useful life. High-end tile may be the only exception, but it comes with a high price tag and is also much heavier (1.5 psf vs. 5 to 8). Mounting solar to tile is a bit complex and very tricky to do without breaking tiles so the cost is also much higher than mounting to metal.
Avoid the Cost of Mid-Life Re-Roofing
When solar is installed on a roof with a shorter life expectancy than the solar system itself, it creates an expensive problem mid-life: dismantling the system, re-roofing, and re-installing everything, significantly increasing overall costs. This is why metal is the best choice for any retrofit involving solar installation. (See diagram 1.)
A number of exorbitant costs associated with completing a PV system/re-roof for a traditional (non-metal) roof include:
• Removing PV modules and racking system
• Decommissioning and re-commissioning the system
• Re-roofing labor and materials
• Reinstallation of the PV system
• Risk of damage to components or wiring
• System downtime, loss of energy production
With a metal roof, these costs are avoided entirely because the roof will still be going strong long after the solar array reaches the end of its life. (See Diagram 2.)
Metal Makes Solar Installation Easier
Metal roofing also offers the easiest and most cost-effective mounting method available. Solar modules can be attached directly to the seams or ribs of the roof, which obviates the expensive “railed” systems required to mount PV modules on non-metal roofs.
Standing seam metal roofing provides a distinct advantage as it requires no roof penetrations. This protects the waterproofing integrity and warranty of the roof while eliminating the need for mounting rails or additional structural supports. Other benefits of metal solar mounting include:
• Fewer components
• Lightweight materials—important in retrofits where the structural capacity may be limited
• Better load distribution
• Fast, secure mechanical attachment
• Lower labor costs
Sustainability, ROI & Long-Term Value
Beyond performance, metal is the most sustainable roofing material available. With an average recycle rate of 98% according to Modern Steel Construction (EAF statistics, May 2023), steel is one of the most recycled materials in the construction industry. It’s also fire-resistant, low-maintenance, and can withstand extreme weather conditions. Pairing metal roofing with solar PV results in a system that is:
• More environmentally responsible
• Lower in lifecycle cost
• Higher return on investment
• Better aligned in service life and durability
The roof and the PV system should be treated as an integrated single asset that delivers the best financial and operational outcome.
A Shift Toward Durable Retrofit Solutions
Today’s building owners are increasingly aware of the pitfalls of short-term thinking. The old mentality of “buy it cheap and replace it later” is losing favor, particularly among younger generations, who now demand long-lasting, low-maintenance construction with durability, energy efficiency and sustainability as a priority.
These trends are especially evident in the re-roofing market, where metal roofing has a significantly larger share than in new construction (within the residential market). That’s because more building owners are now choosing durable, future-proof systems—and pairing them with solar.
As the cost of solar has decreased significantly over the past decade, and with additional momentum from federal and local incentives as well as public policy mandates, the combination of metal roofing and solar PV has become even more financially attractive. The breakeven point and long-term ROI improve every year—especially with solar on metal roofs due to lower initial costs—making this pairing a smart and economically sound choice for retrofit projects.
Main Takeaway: Retrofit The Right WayTM, the First Time
If a building needs a new roof and the owner is considering solar, retrofit it once and do it The Right Way. Installing a 30+ year solar system on a 15 or 20-year roof is like mounting a Ferrari engine on a Mini Cooper chassis. It’s simply not built to last, and the consequences are expensive.
Building owners and roofing professionals must consider both the roof and solar system as a unified investment. Metal roofing is the most solar-compatible, cost-effective, and sustainable option for retrofit and re-roofing projects. It simplifies installation, avoids future liabilities, and maximizes ROI. MR
About the Author
S-5! CEO and Founder Rob Haddock is a former contractor, an award-winning roof-forensics expert, author, lecturer and building envelope scientist who has worked in various aspects of metal roofing for nearly five decades. He began ground-breaking innovation of penetration-free ancillary S-5! attachment solutions in 1991 and holds 200+ U.S. and foreign patents. Together with his sons, they co-invented a rail-less direct-attach solar solution that provides a simple, secure method to “lay & play” PV modules with tested, engineered, cost-saving attachment to the only roof type that outlasts the solar—the metal roof.
