Solar Basics: Roof-Mounted vs. Ground-Mounted


When a business goes solar, one major decision is the type of system that is best for the site: roof-mounted or ground-mounted? In this blog, we will break down some of the major distinctions and discuss when one type would be better suited for certain sites.

What Is a Roof-Mounted System?

In a rooftop solar system, photovoltaic panels are mounted on the roof of a building, as the name suggests. This type of solar installation is ideal for flat roofs that are 100,000 square feet or more. Rooftop systems are lightweight, compatible with roof warranties and built to withstand wind, rain and even hail.

There are a few options for installing roof-mounted solar systems. To avoid penetrating the roof surface, some installations use a ballasted installation, a mechanism in which the panels are weighted down rather than physically attached to the roof. The roof must be able to hold the weight of the ballasts combined with the panels to allow this type of installation. For roofs with a lower weight limit, an attached system might be the preferred option. In some cases, a hybrid installation is used, combining ballasts with some attachments.

The benefits of a roof-mounted system include:

  • Fewer environmental permits are required
  • Utilizes unused space on roofs
  • Not easily accessible to unauthorized personnel

There are certain factors to consider for solar rooftop applications that include the structural capacity of the building, age of the roof and warranty, presence of roof-top units and accessibility for any maintenance purposes. An experienced solar developer can ensure that your roof warranty is not compromised during the installation.

What Is a Ground-Mounted System?

A ground-mounted system is an installation that can be mounted on rails anchored into the ground or ballasted with concrete anchors to avoid disturbing the soil (often an issue around brownfields and other sensitive sites). Ground-mounted solar systems may also have tracking capabilities that change the panel tilt throughout the day to maximize sun exposure. In certain locations, a ground-mounted system can be constructed as a parking canopy, providing shade or snow cover to parked cars while capturing valuable solar energy.

A ground-mounted system has a host of benefits, including:

  • Ease of access for repairs and cleaning
  • Making use of otherwise unusable land, such as environmentally sensitive sites including brownfields and parking areas
  • Tends to have fewer space constraints than roof and can therefore be larger

While these systems require large areas of land, it can be a great use of buffer land close to a facility, otherwise unusable land, such as brownfields, or parking area coverage. They can create eco-friendly habitats by incorporating solar grazing that uses sheep to maintain the grounds and pollinator-friendly installations that help support a healthy habitat for bees and butterflies.

Which System Is Right for Me?

The choice between a roof-mounted or ground-mounted solar system will depend on the logistics and available space at your specific installation site. If you have a large facility with ample roof space, rooftop panels may be the best choice for your business. Dimension Fabricators, a major supplier of concrete reinforcing steel products to the construction industry, installed a roof-mounted system at a facility that produces 99 percent of the site’s electricity needs. In New York City, Cornell Tech deployed an innovative canopy mount (in which the solar panels do not sit directly on the roof) that supplies electricity for two of the school's main buildings as part of its sustainability plan. The biopharmaceutical company, Regeneron, completed a solar system mounted on the roof of a new parking garage that provides energy at the company's headquarters at Tarrytown, NY.

If you have a large corporate campus with available land, it may make sense to choose a ground-mounted system. In Halfmoon, NY, Stewart's Shops installed an offsite ground-mounted system that provides energy to several of the chain's store locations, which lack the optimal conditions for onsite solar power. The reinsurance company, Swiss Re, installed a ground-mounted array on its scenic campus in Armonk, NY, offsetting their onsite energy consumption by 62 percent. Additionally, the imaging electronics and printing equipment company, Ricoh, is continuing to work towards its goal of 100 percent renewable energy use by 2050 by installing a ground-mounted solar system at their facility in West Caldwell, NJ.

Sometimes a site can support both kinds of installations. For instance, GIANT Food Store's support office in Carlisle, PA, deployed a rooftop solar system and is currently completing a pollinator-friendly, ground-mounted system that combined will offset 100% of the facility’s electricity needs.

No matter which system you choose, an experienced solar installation company will work to make the installation of your system as minimally invasive as possible so your business is not disrupted. For more than 10 years, PowerFlex has provided turnkey solar and energy storage solutions to clients such as Amazon, Target, and Bloomberg that help lower energy costs, increase property value and meet sustainability goals. We manage all aspects of the solar project, from development to execution and asset management, and work with real estate owners and tenants to make the process as simple and seamless as possible. Contact us today for a free solar assessment.