Lumber ? ? ?

[charlie_the_tuna]

hey lumbo, my house is a spanish colonial built in the teens and i have a problem with my stairs. i have two sets of stairs, one to the basement and one to the second floor. they are on top of each other running parallel to each other.
i cut some 2x8's on a 45 and shored up the basement stairs because they started to sag on one side but the stairs leading to the second floor are not level. they seem to be, not caving in but just kinda sinking on one side. the side on the outside wall of the house seems to be ok but the side on the vestibule is just coming down. structurally, they seem fine but at some point my wife wants us to move upstairs and i figure i should try to fix before it gets too bad.

what do you do in a situation like this?

jack them up somehow?

i installed replacement windows and siding for years but saving an old house is beyond my know how.