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Can You Put Solar Panels on a Flat Roof?

Solar for Businesses | 3 min read
Installing solar panels on a flat roof

Yes, you can install solar panels on buildings with flat roofs. And they don’t just work; they can thrive. 

Flat roofs tend to appear on larger, commercial buildings. Whether they’re warehouses, manufacturing facilities or something else, these types of buildings tend to use a lot of electricity. And the more electricity used at these facilities, the more money their owners can save with solar energy.

If you’re in charge of a flat-roofed building and you’re looking to install solar panels, we’ve assembled this blog for you. Read on for all the need-to-know information for a successful solar installation.

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How Are Solar Panels Installed on Flat Roofs?

The most common method of installing solar panels on a flat roof is using the ballast mount method. 

This type of installation doesn’t typically require any roof penetrations. Instead, the solar panels are held in place with weights.

A metal racking system is laid on the flat roof, and the solar panels are screwed into place on the rack. Then, heavy concrete blocks are placed on the racking system to secure them to the roof.

When designing your system, your installer will calculate how much these blocks need to weigh to keep your system safe and secure, even in the heaviest winds. 

While ballast mount systems are often the preferred installation method for flat roofs because, in most cases, they do not require any roof penetrations, they won’t be suitable for all buildings.

Ballast-mounted solar systems are much heavier than other types due to the added concrete blocks. Your building will need to handle that added weight, and not all flat roofs are designed to do that. 

If this is the case, your solar installer can still install a solar panel system on your flat roof, but they will need to penetrate the roof to do so. Most times, a third-party roofing contractor will do these penetrations. 

Many may be wary of penetrating their roof, as issues with leaking can create big headaches and expensive repairs. However, solar systems installed on flat roofs shouldn’t have any issues. The attachment equipment is specifically designed to keep your roof safe and keep what lies beneath it dry.

How Much Does It Cost To Install Solar On A Flat Roof?

In most cases, installing solar panels on a flat roof will be comparable in price to a similarly sized system installed on a sloped roof. 

Paradise Energy installers working on a ballast mount solar systemYour solar installation team can install solar panels on a flat roof more efficiently and more safely than on a sloped roof. This goes a long way when transporting solar panels and other equipment up to and around the roof. Installation ease means your team can get the job done more quickly and efficiently, which can lead to lower costs. 

Overall, the cost works out to be about the same as a comparable system installed on a sloped roof.

Are Flat Roof Solar Systems As Efficient as Systems on Pitched Roofs?

Solar panels installed on a flat roof can be just as efficient as panels on a sloped roof, if not more so. 

The more sunlight your panels are exposed to, the more free electricity they’ll generate. The tilt and orientation of your panels can play a role in this.

With a sloped roof, the tilt and orientation are fixed variables set by the roof itself. With a flat roof, your panels can be installed at the optimal tilt and orientation. This can lead to a more efficient solar system. 

Ephrata-Business-Center_Ballast-Mount-Solar-SystemTilting your panels can be beneficial beyond just efficiency. Some manufacturers require at least a slight installation tilt for their warranty, as water can puddle and cause issues. Additionally, snow will clear off tilted panels more quickly than panels installed with no tilt. This angle helps snow slide off once the panels begin to warm, instead of waiting for the sun to melt all the snow. 

In addition, flat roofs are a great location to install bifacial solar panels. Many flat roofs are covered with material that has a reflective surface. Bifacial panels can take the reflected sunlight and turn it into energy. 

What Are the Risks of Solar Panels on Flat Roofs?

When it comes to a solar panel flat roof mounting system, there are relatively few risks. 

In most cases, solar panels can be installed without roof penetrations with a ballast solar mounting system. However, in some instances, especially with smaller flat roofs, penetrations may be necessary. That said, even if penetrations are required, you can rest assured your roof will be safe from leaks and other related issues. 

Another potential risk can be the additional weight of the solar system. Before your system is installed, a third-party structural engineer will analyze the system’s design and your roof’s structure. They’ll ensure that your roof can withstand the weight before signing off on the project.

One last thing to consider is the additional equipment that is on your flat roof. HVAC units and other mechanical equipment may already have their own space on the roof. Your solar panels will have to be installed around these additional machines and in a way that accessing this rooftop equipment is safe and easy. 

Solar Systems on Flat Roofs Can Save Businesses Money

Not only can solar panels be installed on flat roofs, but they can thrive. 

Depending on your specific roof, they can be installed with little to no roof penetrations, and they can be laid out in a manner that will optimize the production of free electricity. They’ll likely be out-of-sight from all but airplanes and birds, meaning you won’t have to worry about them impacting the aesthetics of your building.

By installing a solar system, you can dramatically reduce your electricity bill, cutting operating costs and freeing up more capital to enhance your business. Solar panels can also reduce your company’s environmental impact, which can go a long way with employees and customers. 

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