In most cases, installing solar panels on a flat roof does not require planning permission. However, it's important to note that building regulations and requirements may vary depending on your location. It is recommended to consult with your local authorities or a professional solar installation company to ensure compliance with any regulations or permits that may be necessary in your specific area.

While planning permission might not be required, it's still essential to consider other factors when installing solar panels on a flat roof. These include the structural integrity of the roof, the weight-bearing capacity, and the orientation and shading of the roof. Additionally, proper installation techniques should be to ensure the panels are securely attached and do not pose any risk to the roof, the building, or the occupants.

Overall, it's wise to consult with experts in solar installation and local building regulations to determine the specific requirements and considerations for installing PV panels on a flat roof in your area.