I am building a rooftop deck on top of my garage and need to have the roof repaired before I can start. There are spots where it leaks into the garage. I also need to have a gutter installed. It is a flat roof with a slight incline. I am not sure what type of roof would be best, but I would need it to last for a long time since there will be a deck built on top of it. The roof is 23ft by 13.5ft.