I recently sat down and talked with Shawn Schreiner from True South Solar of Ashland to learn more about the solar industry and how the installation of solar arrays impacts the structures they are supported on. Shawn has been working with Principal Owner Eric Hansen since the start of True South Solar 10 years ago. Shawn is currently the Sales and Operations Manager. He is responsible for getting projects online and approved for installation.
Typically, each solar project requires structural and electrical permits. DEI has had the pleasure of assisting Shawn and True South Solar with structural permitting on projects that require engineering. Typical residential projects in Oregon can be permitted using prescriptive methods that do not require engineering support. Commercial projects, ground mounted solar arrays, and non-conventional installations all require engineering.
Shawn described the typical solar installation connection for wood framed roofs as a mounting plate that lags to the roof framing, is then flashed and waterproofed, an L foot bracket is attached and this holds the rails that support the solar panels. The connections occur every 4 feet to meet prescriptive requirements and are usually staggered by 2 feet, at alternate framing supports, to distribute the load more evenly to the structure below. The ends of the rails are supported, with the connection described above, to the framing at 2 feet on center.
There are also ballasted systems that use weight to hold the solar arrays and framing support onto flat roofs with membrane-type roofing. These systems are generally used for commercial buildings and the installations require engineering review.
We also discussed some important things to consider if you want to plan for solar on your project, whether it is now or in the future. The most important item to consider is building orientation. South-facing roofs with ample space for panels are recommended. You should also plan for an additional dead load of 3.5 to 5 pounds per square foot in the roof framing design. If you are planning a new project and are interested in installing solar panels you will want to get your solar company involved early in your design process.