• Mark Forbes

Solar Panels and Commercial Roofs

Building owners are more frequently considering solar panel installation on their roofs, partially for the benefits to the environment and partially for the benefit of reducing utility expenses. However, there is more to consider than environmental benefit and expense reduction. Some factors that must be considered when investigating this option are roof design, type of installation, placement of the panels, and the energy consumption profile of your building.


The first thing that building owners should consider when thinking about solar panel installation is the design of the roof. Ideally, flat roofs are best suited for solar panel installation, though not all flat roofs can accommodate the added ballast weight. Some roofs are designed specifically with the intention of solar panel installation. However, if that is not the case for your flat roof, and your roof can handle the added weight, your building will first require an inspection to determine the type of load it can handle and if it will need to be replaced during the ”lifetime” of the solar panel system. United Materials has qualified roofing professionals to assist business owners with these inspections and assessments.


The primary method of installation is known as “ballasted racking,” which employs a mixture of “ballast” (often heavy concrete blocks) and penetrating anchors and has a straightforward installation process. It can have the advantages of few or no roof penetrations and less weight. Flat roofs are also easier to inspect. Some of the disadvantages of this method are that some local municipalities limit the use of this process, they may require advanced wind-load evaluations, and they run an increased risk of leaking.


The mounting technique for installation on sloped roofing is known as “attached racking.” This method requires penetration of the roof. There are different variations of this system, in that this type of installation depends on roof design and structure, load capability of the roof, the design of the solar panel system, and local building codes. Some advantages of this system are that they can be used on flat or sloped roofs, and more municipalities allow their usage than ballasted racking. Disadvantages of this method are that they can be more difficult to install and that any mistakes in roof penetration can negatively impact the roof’s structural integrity.



How the solar panels are positioned on your building’s roof will greatly affect how efficiently they perform for your building, and for your business’s bottom line. Solar panels need to be angled or tilted in ways that promote optimal absorption of the solar rays throughout the day. Solar panels also need to be free from shadows, so while commercial buildings are not often shaded by trees, the sun’s position and the shadows cast throughout the day should be considered in panel placement and installation.


Your building’s energy consumption profile is another important factor to consider when installing solar panels. This profile contributes to the process of placement and size of your solar panel array. If your system is too big, your business will rack up unnecessary costs. If it’s too small, your business will see only minimal financial benefit. Be sure to determine whether your business will be able to benefit from net metering through local utility companies, which is not available in some areas. If not, then your solar array should be designed to avoid overproduction. If net metering is available, then your solar array should be designed to maximize that benefit as well, keeping in mind that there are typically maximum credit limits for net metering. Don’t expect to get a utility bill for $0.00, however. Most power companies will roll over credits from month to month.


If your business is considering solar panel installation for your building, contact us at United Materials for a thorough inspection and assessment to assist you in making this decision. Let us help you ensure that your roof is ready for this type of work.



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