A loader device is disclosed for moving cargo to and from a vehicle roof. The loader, attached to trailers or other vehicles includes a channel, a carriage and a winch. The carriage, powered by the winch, travels up the channel to raise cargo to the vehicle roof. The carriage travels down the channel to lower cargo from the vehicle roof. Rungs attached to the channel form a ladder for human access to the vehicle roof. When not in use, the carriage folds to assume a smaller profile.