The solar rooftop structure array of a PV system can be mounted on rooftops, generally with a few inches gap and parallel to the surface of the roof. If the rooftop is horizontal, the array is mounted with each panel aligned at an angle. The installation of the solar panels can be undertaken by the crew responsible for installing the roof. For a small minority of roofs (often not built to code) that are designed so that it is capable of bearing only the weight of the roof, installing solar panels demands that the roof structure must be strengthened before-hand.

In all cases of retrofits particular consideration to weather sealing is necessary There are many low- weight designs for PV systems that can be used on either sloped or flat roofs Recently, tension- based PV racking solutions have been tested successfully that reduce weight and cost. The general practice for installation of rooftop-mounted solar panels include having a support bracket per hundred watts of panels.