Can you install solar on a flat roof?
When you imagine a solar installation, you may see one of two things: a utility-sized ground-mounted solar PV system or a rooftop solar panel system. If you have a flat roof, you may not realize that solar energy can also be a good fit for your type of property. Flat roof solar panel systems are actually more flexible in design than tilted roof installations, making it easier to take full advantage of solar panels.
There are different design considerations when you install flat roof solar panels on a sloped roof or have them ground mounted - and flat roof setups are no exception. When you're looking for a solar company, you may encounter installers who don't work on flat roofs, especially if you don't live in an area where they're common. Some of the larger national solar leasing companies won't install solar on flat roofs because they use a limited selection of equipment and standardize their system designs to minimize costs.
Challenges of Installing Solar on a Flat Roof
Whether you have a regular asphalt roof, a metal roof, or a flat roof, it's common to run into some challenges when installing a solar panel system, but they're usually easy to remedy (depending on your setup). However, when you install solar panels on a flat roof, there are some unique and common issues that can arise, including:
If you place solar panels flat on a flat roof, they will get dirtier over time because they are not mounted at an angle; dirt reduces the yield, so you'll need to clean the panels more often than before.
In the U.S. (and throughout the Northern Hemisphere), the sun crosses the southern part of the sky from east to west throughout the day. South-facing solar panels will have the best energy production - if you put them flat on a flat roof, you'll miss significant output.
Many manufacturers include clauses that void the warranty if the panels are mounted flat on a flat roof; there is an increased risk of water damage because water can collect on top of the panels and sit there. However, this is easily remedied by mounting the solar panels at an angle on a flat roof and letting the rain (or anything else) run off of them.
Some installers don't work on flat roofs to keep costs low - make sure to indicate that your roof is flat when shopping around for quotes to get in touch with an installer who will work on a roof like yours.
Fortunately, you should be able to avoid these challenges as long as you mount your solar panels at an angle on a flat roof and shop around.
Does it cost more to install solar on a flat roof?
Labor and installation costs typically account for about 10% of the total cost of a solar PV system. This is due in part to the logistics of climbing around on a steep roof to secure the solar panels and their mounts. In contrast, installing a solar panel system on a flat roof is a much simpler process - workers are free to move around on the roof without special equipment, and most roofing materials used on flat roofs can easily handle the wear and tear that occurs during installation. Typically, flat roof solar panel installation costs are competitive with standard sloped roof installations.
As an added benefit, your solar installer does not need to penetrate the roof to install flat-roof solar panels. Solar installations on sloped roofs typically use "penetration mounts," which are racks that secure the solar panels to the roof by drilling multiple holes. Flat roof systems typically use a weighted mounting system (called a "ballast system") that uses gravity to sit on the roof without drilling holes.
That said, solar panels mounted on flat roofs sometimes require specialized equipment to maximize their power production. Instead of laying flat solar panels on a sloped roof, your solar installer may use tilt brackets that tilt the solar panels upward so they are exposed to as much sunlight as possible during the day. This can sometimes result in a slightly higher price for your flat roof solar panel system.
When you imagine a solar installation, you may see one of two things: a utility-sized ground-mounted solar PV system or a rooftop solar panel system. If you have a flat roof, you may not realize that solar energy can also be a good fit for your type of property. Flat roof solar panel systems are actually more flexible in design than tilted roof installations, making it easier to take full advantage of solar panels.
There are different design considerations when you install flat roof solar panels on a sloped roof or have them ground mounted - and flat roof setups are no exception. When you're looking for a solar company, you may encounter installers who don't work on flat roofs, especially if you don't live in an area where they're common. Some of the larger national solar leasing companies won't install solar on flat roofs because they use a limited selection of equipment and standardize their system designs to minimize costs.
Challenges of Installing Solar on a Flat Roof
Whether you have a regular asphalt roof, a metal roof, or a flat roof, it's common to run into some challenges when installing a solar panel system, but they're usually easy to remedy (depending on your setup). However, when you install solar panels on a flat roof, there are some unique and common issues that can arise, including:
If you place solar panels flat on a flat roof, they will get dirtier over time because they are not mounted at an angle; dirt reduces the yield, so you'll need to clean the panels more often than before.
In the U.S. (and throughout the Northern Hemisphere), the sun crosses the southern part of the sky from east to west throughout the day. South-facing solar panels will have the best energy production - if you put them flat on a flat roof, you'll miss significant output.
Many manufacturers include clauses that void the warranty if the panels are mounted flat on a flat roof; there is an increased risk of water damage because water can collect on top of the panels and sit there. However, this is easily remedied by mounting the solar panels at an angle on a flat roof and letting the rain (or anything else) run off of them.
Some installers don't work on flat roofs to keep costs low - make sure to indicate that your roof is flat when shopping around for quotes to get in touch with an installer who will work on a roof like yours.
Fortunately, you should be able to avoid these challenges as long as you mount your solar panels at an angle on a flat roof and shop around.
Does it cost more to install solar on a flat roof?
Labor and installation costs typically account for about 10% of the total cost of a solar PV system. This is due in part to the logistics of climbing around on a steep roof to secure the solar panels and their mounts. In contrast, installing a solar panel system on a flat roof is a much simpler process - workers are free to move around on the roof without special equipment, and most roofing materials used on flat roofs can easily handle the wear and tear that occurs during installation. Typically, flat roof solar panel installation costs are competitive with standard sloped roof installations.
As an added benefit, your solar installer does not need to penetrate the roof to install flat-roof solar panels. Solar installations on sloped roofs typically use "penetration mounts," which are racks that secure the solar panels to the roof by drilling multiple holes. Flat roof systems typically use a weighted mounting system (called a "ballast system") that uses gravity to sit on the roof without drilling holes.
That said, solar panels mounted on flat roofs sometimes require specialized equipment to maximize their power production. Instead of laying flat solar panels on a sloped roof, your solar installer may use tilt brackets that tilt the solar panels upward so they are exposed to as much sunlight as possible during the day. This can sometimes result in a slightly higher price for your flat roof solar panel system.