deckframingstairs
I have a deck design where I want stairs coming down perpendicular to the joist starting at the end of the joist. You can see the picture as a generic not to scale drawing of what I mean.
I had an idea to have the end joist extend past the rim joist. I then want to attach the stair stringer to the very end of the joist. I am going to use USP's concealed stringer hanger.
Am I able to put a stair stringer like this, or is there a different/better way to get the stairs flush with the rim joist?
I guess I'm curious why you wouldn't simplify the layout like this:
Yellow = deck joists
Green = support beams
Your decking would run diagonally over the joists. If you use 2x boards for decking, that should be fine if the joists are 16" on center. If you want to use 5/4 decking, you should probably put the joists 12" on center so that the diagonal run is closer to 16".
If I understand your description correctly, you have a maximal load area of ~38 ft². If so, 4x4s are more than sufficient for the posts. (Check your trusted load tables; don't believe some random guy on the Internet.) If you replace some posts there is no harm in upgrading them to 6x6s, but I don't see a reason to sister onto the existing 4x4s.
However, it sounds like there is so much rot that it will be easier to tear down the entire deck and build a new one. If you do that, the new deck will of course need to meet current code requirements.
Best Answer
Double beam the ledger, Notch out a rail seat .65 inches, Set stringers in place, Pre drill 3/4" pocket hole horizontally from stringer into ledger (will need 12" to 14" auger bit), Use 1/2" structural screws to secure stringer to ledger, Plug hole with hole plugs or mix sawdust with sandable titebond glue and patch hole.
Additionally, stringer 14ga prebent metal underneath each stringer, stubby nailed to ledger will help support weight if it's high off the ground.