A roof assembly for attachment to reinforcement beams in a fixed roof of a vehicle comprises a frame surrounding at least a part of an opening and configured to be attached to at least the reinforcement beams of the vehicle. The frame is made primarily of plastic material. At least a first stationary panel is at least partly semi-transparent and is at least partly fixed to the frame. At least one movable panel is arranged adjacent the stationary panel. A reinforcement is integrated in the frame. The reinforcement extends at least around an area covered by the movable panel, and along at least a portion of the frame configured to be attached to the reinforcement beams of the vehicle.