I have a house that is 50 years old. The previous owner added a section on the back half of it. However, the roof itself has a low angle and holds water during rain. Lately, the ceiling under the roof in the kitchen and bedroom have been leaking. I've been thinking of building up the roof, making it level with the highest point on the house, and then placing shingles on the top. I'm also thinking of adding a second story later on down the road once I get the roof fixed. Anybody have any suggestions about to go about this problem?