The installation of a photovoltaic system on a flat roof is not limited by the slant imposed by the house design. The angle of inclination of the modules should be \( 15-20_{}^{o} \) in order to maximize the surface coverage and prevent wind effects. The system of mounting PV modules on a flat roof requires the use of a frame made mostly of aluminium profiles that allow adjusting the angle of inclination of the photovoltaic modules. Three types of flat roof mounts are possible:

• unballasted installation system,
• ballasted installation system,
• self-supporting installation system.

Systems of up to 10 kW can be installed on the roof, while larger systems should be installed on the ground. The steps for installing on the ground are similar to those for a flat roof without ballast. The exception is how to attach the support structure to the ground.