Over the past four decades, more than 2 billion square feet of metal roofing has been installed in the United States each year. That number continues to grow, and it’s more than any other type of roof except asphalt shingles.
The roots and technology of metal as a coating material go back over 3,000 years. It has always been coveted as a premium roofing option but, until more recent history, has been handicapped by higher upfront costs than alternatives. Beginning in the mid-1800s and continuing into the present day, production technologies and the use of aluminum and coated steel sheets began to narrow the premium price gap. Now it rivals other premium roof materials, but lasts two to four times longer.
Current trends tend to assess the long-term costs of owning a roof, as landfills are overloaded with old, discarded construction items due to short-term, budget-conscious construction goals. The life cycle costs and environmental appeal of metal provide many benefits. As a result, metal is becoming the roofing material of choice for both commercial and residential applications.
Metal roofing is known for its durability, durability and versatility and is gaining popularity in the solar energy market. The metal roof is the ideal host for mounting photovoltaic (PV) panels because it is the only type of roof whose lifespan actually exceeds the lifespan of a solar photovoltaic system.
In the commercial/industrial market sector, the field/laboratory study published by the Metal Construction Association indicates that the service life of coated (standing seam) steel is in the order of 70 years. Most alternative roof systems will expire well before the life of the PV system. This leads to costly disassembly of the photovoltaic generator, repair of the roof and reassembly.
The lifespan of solar PV is between 28 and 37 years with an average of 32.5 years, according to a Berkeley study. Aside from metal, there are no other types of roofs that live up to it without requiring replacement. High-end slate or tile may be the only exception, but it comes at a high price and is also much heavier (5-8 psf versus 1.5). Solar mounting on tiles or slate is a bit complex and very delicate to do without breaking so the cost is also much higher than mounting on metal.
Ease and cost of installation – “trackless”
It is easier and cheaper to mount solar energy on a metal roof than on any other type of roof.
The uniqueness of metal roofing is that the structural ribs or seams can be used as inherent (and free) “rails” for mounting solar PV panels via reliable mechanical fasteners, so the need for a rail system traditional is eliminated.
Direct attachment of solar modules to a metal roof can be accomplished with fewer components and lightweight materials, resulting in better load distribution and zero penetration, which both preserves the integrity of the roof and roof manufacturer’s warranty.
Because there are no rails, the hardware required for a mounting system is reduced in weight (up to 85%) and savings on durable goods (up to 35%).
The key to labor savings (30-50%) is the simplicity of trackless fastening: requiring 65-75% fewer components, the roof clamps are aligned and installed as the modules are installed “on the fly”.
Finally, shipping long lengths of rail to project sites and hauling them to a rooftop is expensive and often a logistical nightmare. With trackless accessories, mounting system shipping costs can be up to 60% lower than track mounting systems, with less logistical hassle to transport the product to distribution, then site, then inside the site and on the roof. A traditional 750 kW rail system would normally require a semi-truck for transportation; a trackless mounting solution could fit in a short bed van.
Whether tracked or trackless, the simplicity and cost savings of mounting to a metal roof is significant, and the future need for roof replacement is avoided.
Metal roofing is the most sustainable type of roofing (with an 85% recycling rate, steel is one of the most recycled building materials available). By installing solar power on metal roofs with reduced material, labor and shipping costs, the trackless mounting solution proves to be a “green” innovation in the energy industries. solar and roof.
Recyclable metal roofs have a proven lifespan many times longer than any other type of roof and are never destined for a landfill. Therefore, metal roof solar mounts allow installation on most old roofs without roof replacement. Producing trackless systems saves around 90% of the energy used to produce track supports and 85% of carbon emissions in transportation.
Once the decision has been made to install solar energy, a new roof is often necessary. Metal roofing has become a driver for roof type selection in many cases because not only is a metal/solar roof system initially cheaper than other roof system combinations, but it also leads to system return on investment (ROI) improvements. . Therefore, the photovoltaic generator and the roof should be considered as a single asset.
When calculating ROI in solar pro forma, inverter replacement is usually factored in at around 15 years – but what about the cost of replacing the roof? The solar panel must be completely disassembled and then reinstalled on the replacement roof. Often, even the initial cost of the solar + metal roof is lower than that of the solar + other roof type alternatives. Factor in the roof replacement and the cost benefits become grossly magnified.
A number of exorbitant expenses associated with retrofitting a photovoltaic system for a traditional (non-metal) roof could include: removal of solar modules; remove the mounting and shelving system; the decommissioning of the system during the repair of the roof; roof repair; reinstall the PV system; restore the system to service; the potential for damaged components during this process; possibly requiring new wiring and loss of power generation during downtime.
With metal, you can avoid roof replacement due to its long life. The roof will remain solid long after the life of the solar generator has expired.
The rise of metal roofing and solar
With the cost of solar power dropping dramatically over the past decade, in addition to federal and local incentives as well as public policy mandates driving solar power’s popularity, break-even and return on investment improves every year – which is even more evident with solar on metal roofs due to its lower installation costs, which makes even more financial sense.
Metal is the most solar friendly roof available and the PV contractor should know that.
Metal roofing is attractive, durable, non-flammable and requires almost no maintenance. The “buy it cheap and fix it later” mentality has steadily diminished over the past few decades and more and more building owners are choosing metal like never before.
The growing demand for more sustainable and environmentally friendly building materials, as well as methods that reduce maintenance and have a longer lifespan, is on the rise – as evidenced by statistics clearly indicating that metal occupies a much larger share of replacement roofing than it does in new roofing in the residential market.
Solar contractors need to know about roofing alternatives and their lifespan to add value to their customers. The long-term costs of the rooftop and solar PV should be assessed as one system. Advise mounting a solar panel with a lifespan of over 30 years on a TPO or asphalt shingle roof with a lifespan of 15 years is a bit like mounting a Ferrari engine on a Mini-Cooper chassis. Who would do that?
For more information, videos and webinars on this topic, please visit www.s-5.com and learn more about the key factors to consider when mounting solar on your metal roof.
Rob Haddock is CEO and Founder of S-5! is a former contractor, award-winning roofing forensics expert, author, speaker, and building envelope scientist who has worked on various aspects of metal roofing for five decades. He began the breakthrough innovation of non-penetrating auxiliary accessory solutions in 1991 and holds over 60 US and foreign patents. Together with his son, Dustin, they co-invented a trackless direct mount solar solution that provides a simple and secure method to “lay and play” photovoltaic modules with a tested, engineered, and cost-effective mounting on the only typical roof that lasts. longer than solar – metal roof.
The views and opinions expressed in this article are those of the author and do not necessarily reflect those of photo magazine.
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