I currently have a poured concrete patio out my back door (sliding patio door). It is two steps down (24 inches) from the door to the patio. I'd like to build a deck that is at the height of the back door. Several questions. 1. Should the deck be a few inches below door level or level with the door. 2. Can I stand the 4x4 supports directly on the poured patio? The deck size will be the same size as the patio and the patio is solid and does not frost heave. 3. How should I leave access to get under the deck for clean out of leaves and debris? 4. Any pitfalls in doing this?