Most of the time no. Main requirements to avoid planning are; The new installation of panels does not excess 200mm of the existing roof. The panels must be over 1m from the edge of the roof. Areas of outstanding beauty or conservation areas require the panels do not face the road. The position of the panels should be positioned in the least visible place to minimise the appearance of the building (this typically isn’t a problem on the roof of commercial buildings. Listing buildings will require planning permission prior.