The live load on a roof is the weight of any temporary objects on the roof. Where snow isn’t a problem, the live load can come from people working on the roof and any equipment they take on to the roof with them.
Accurate solar panel roof load calculations can ensure that your investment will pay off. If you live in an area where winter weather is frequent, it’s important to account for the snow load when factoring in if solar will fall within the roof’s available capacity.
Ballasted, unattached PV systems on low-slope roofs have to meet seven conditions to comply with seismic load requirements in Section 13.6.12. For low-profile systems, the height of the center of mass of any panel above the roof surface must be less than half the least spacing in plan of the panel supports, but in no case greater than 3 feet.
The roof must be able to support the sum of its dead load and any anticipated live load, so the roof has to be designed with a load limit that takes into account both of these loads. A typical roof is expected to support a live load of 20 psf; this minimum live load is in addition to the dead load that the roof must bear.
If you live in an area where winter weather is frequent, it’s important to account for the snow load when factoring in if solar will fall within the roof’s available capacity. The blueprints of your house will typically list your snow load capacity, but structural engineers can also assess your roof’s snow load as well.
The point load represents the pressure applied to specific points where the solar panels and their mounting hardware attach to the roof. It’s like pinpointing exactly where your roof will need to support more weight to ensure those spots can handle it without any issues.