I have a sunken backyard concrete patio which is sloped for drainage. The slope reduces usability for sheds, BBQs, picnic tables, etc. The space is approx 15' x 25', with concrete walls on 3 sides. The 4th being the house (wood siding).
The back door opens out onto a concrete step/platform which then drops 7-1/4" down to the patio. The first step of the stairs on the other side is 7-1/4" up from the patio. The max depth from this level line is 10-1/4".
My plan is to use 2x6" joists 16" OC running from the house to the retaining wall (15'), attached to joist hangers on a ledger (bolted to concrete wall). The joists will support 2x6 or 5/4 deck boards (undecided). All joists/ledgers will be pressure treated.
Q: Can I run a single joist 15' from one side of the patio to the other, or do I need a beam half-way across, or maybe blocking between each joist?