Can solar panels be mounted on a metal roof?
Metal roofs are durable, low maintenance, and they look great. But can you mount solar panels on them?
The most common roofing material in the United States is asphalt shingles, and for good reason: they’re inexpensive, durable, and come in a wide variety of styles and colors. But while they’re less popular, metal roofs have a lot of advantages. If you’re a homeowner with a metal roof, you might wonder: can you install solar panels on them?
The answer is: yes! While the majority of solar homes have asphalt shingle roofs, metal roofs are actually a better choice if you’re planning to go solar. This is because one of the main concerns with a rooftop solar installation is ensuring there’s enough life left in the roof before putting panels on top of them. If a roof fails early, it’s an extra expense to remove the solar panels before the roof repair can proceed. But metal roofs last a really long time, making the age of the roof less of an issue.
How the solar panels are mounted will depend on the exact type of metal roof you have.
Types of metal roofs
There is a large variety of metal roof types that you’ll find on the market. This is the main complicating factor when installing solar on a metal roof in comparison to asphalt shingles. With shingles, the solar racking is attached with feet that are bolted through the shingles into the sheathing underneath. Flashing and sealants are used to make the connection waterproof.
With metal roofs, you might not need penetrations at all. Some mounts can clamp onto raised seams, while others are bolted through the metal. Which one you can use will depend on the geometry of the sheet metal. Below are some of the most common types.
Solar panel clamps for standing seam roofs
A standing seam metal roof is made of individual metal panels that are connected together with a crimped connection that stands vertical to the roof surface. This “standing seam” provides a handy mount point for solar racking.
Every manufacturer of solar racking will have a different design, but with a standing seam roof you can have a clamp that securely grips the seam without penetrating it. This is a great design because it means that you don’t have to worry about permanently modifying the roof and creating entry points for moisture.
Here’s an example of a clamp from the company S-5! (the exclamation point is actually part of their name).
Solar panel brackets for ribbed panels (r-panels)
A ribbed panel metal roof has raised trapezoidal ribs that can serve as attachment points for a solar mount. The mounts for this type of metal panel must be bolted, however. This means drilling through the r-panel and using an adhesive or sealant to ensure that the penetration remains watertight.
In the case of S-5 brackets (pictured below), there is a factory-applied EPDM rubber gasket seal on the footing, which automatically makes the penetration watertight. Other manufacturers may have different approaches.
One thing that you might notice with this system is that it’s railless. On a conventional shingle roof, footings are bolted to the roof, and then rails are attached to the footings. Finally, the solar panels are mounted to the rails.
However, with this S-5 system (and those from many other manufacturers) no rail is necessary because the mount point has a bracket for the panel. This saves both material and installation costs, which will help bring down the cost of your system.
Solar panel brackets for corrugated metal roofs
Corrugated steel roofs are the original type of metal roof. They’re what you might see on a barn or other industrial settings, but they’ve found use on residential homes for people who like the industrial aesthetic.
As is the case with r-panel mountings, solar mounts for corrugated roofs have to penetrate the roof. This means waterproofing is critical.
Below is an example from the manufacturer Solar Connections. Like the S-5 product above, this PowerMount mount includes an EPDM gasket on the base, but the manufacturer does recommend that you apply a bead of caulk as well.
Metal roofs are no problem for solar panels
As you can see, if you have a metal roof on your home or business, going solar is no problem. There are many products on the market that will allow you to mount solar panels.
In fact, metal roofs are the best type of roof to pair with solar panels. Because metal roofs have such long lifespans, there’s much less of a chance of developing a roof leak that will require you to pay the extra cost of removing and reinstalling the solar panels.
And if you have a standing seam metal roof, that’s the best situation of all because you can use a clamp system that doesn’t put holes into your nice roof. This also reduces the installation labor and your system costs.