my garage roof was termite infested before i purchased the house. in the upcoming spring i want to tear off the old roof to put on a new roof. i had built a deck 2 years ago which is around level to the roof, planning on extending the deck ontop of the roof. instead of building a deck ontop of a surface that will be somewhat flat, what kind of roof surface can i put on so it will be walkable. i will be taking out the joists and all existing wood on the roof. sources tell me that there is no kind of roof that is walkable without fast deterioration. there has to be some kind of top i can put on the roof to make it a walkable, enjoyable space. the roof is around 15 by 25 feet.