Most of the solar energy systems we see in our community are installed on pitched roofs or as a ground mount, but what about flat roofs? Unless you have a bird-eye view of the building, you can’t  tell what’s up on the roof.

This may make you wonder whether or not you can have solar panels on a flat roof. The answer to that is yes, and the way many solar panel systems are installed on a flat roof is by something known as a ballast mount. 

How are Ballast Mounted Solar Systems Installed?

Whereas most other roof mounts are secured to the roof beams of the building through penetrations in the roof, ballast mounts are secured with weight. 

The solar panels are attached to a solar racking system. That racking system has trays below the panels on which heavy, concrete blocks will be placed. The weight from these blocks keeps the solar panels in place on flat roofs.

While the system will sit on a flat roof, the solar panels themselves will be installed at an angle in most cases. Installing solar panels at an angle can increase the amount of sunlight they receive, which allows them to produce more electricity. Additionally, a slight angle can also make it easier for snow and rain to slide off instead of accumulating on the face of the panel. 

That said, installing solar panels at a tilt also means they’ll cast a shadow. If that shadow falls on other solar panels in your system, it can inhibit production.

Is Your Roof Right for Ballast-Mounted Solar?

Here are a few things to consider.

Small Roofs May Require Penetrations

The solar panels in a ballasted solar roof mount are secured to a racking system which is then held in place on the roof by weights. For most roofs, this means no penetrations are required to install the system. 

Because most people are wary of putting holes in their roofs, this is a popular selling point for ballast mount systems. However, depending on the size of your roof, penetrations may still be required. Small flat roofs may need additional roofing attachments that have to be secured in through the roof. These attachments will be installed by a third-party roofing company, and may or may not impact your roof’s warranty. 

But because most flat roofs in general top mid-to-large-sized commercial buildings, the vast majority are installed without these additional attachments and with no roof penetrations needed. 

All that said, it’s worth noting that a properly installed roof-mounted system should not leak or cause any issue, regardless of how it’s mounted or the roofing material. Thanks to specially designed attachments and properly installed flashing, no water damage will occur if the system is installed properly and with trusted, quality materials.