We have a walk through basement. The deck coming off the main floor stands a good 8 to 10 feet. I want to use the area under the deck as a shed. Are there any disadvantages in doing this/ What is the best way to put a cover to allow water to drain off. What materials to use? How does one anchor the 'roof'" to the bottom of the deck boards. What slope one needs to incorporate? Please share your thoughts and experiences? Thanks