Looking for insight on how to replace posts in a 9.5" concrete patio. DIY
Info: located in the midwest, existing deck age unknown, possibly original at 34 y/o. The three posts are embedded in a 9.5 inch thick concrete patio. I assume the posts are on equally robust footers and concrete was poured around after. The posts are surprisingly solid at ground level w/ ~1/8 impression from screw driver test. The posts are twisted and one is badly bowed which (along with numerous other issues) makes the deck look off balance and about to fall over, which it is.
I plan to demo and rebuild the deck next month and won't be rebuilding the stairs due to added cost/complexity and b/c there are stairs off the adjacent screened porch. With the existing post spacing a fourth 6x6 post would be needed or else it'll be ~19" over-cantilevered with planned 3 2x12 beams. The new deck will be 12'x25' with 2x8 joists at 12 OC and trex decking.
Anyway, after a lot of searching and chats with AI I'm kind of stuck on the best way to replace the posts. I'd prefer to not have excavate and want to rely on existing footers if possible. Initially I planned to cut posts flush to the patio then drill/chisel to the footing where I'd put rebar pins into the footing and pour a sonotube extension of the footer to 8" above the patio. After discovering the patio depth that no longer seems feasible.
Other ideas are to cut the posts at ~12" off the ground (before the worst of the beam twists and bow) and use 18" or 24", 1/4" in thick metal straps on four sides attaching old and new posts.
I also wonder, to make the new posts symmetrical, if I couldn't just rely on this monolith of a patio to hold them and use Simpson E-Z bases bolted in new evenly spaced locations.
Are either of these realistic? Other ideas? Should I bite the bullet and plan to do new footers?
See deck pics (12 OC and 24 OC joists lol) and sketch of planned deck with existing post locations. Thanks for any feedback!
