I recently purchased my home and during an extremely heavy rainfall the roof in the sunroom to my 1919 Georgian Colonial began to leak. The roof was inspected. The roofer said that the airing deck was in good repair and that no replacing was necessary. A woodburning fireplace - original to the house - seperates the great room from the sunroom. How can I find the leak with their being no problems with the current roof without doing a total gutting of the plaster ceiling.