Floor leveling question

Is the house or room 3/4" out because the foundation setttled? Is this

There are some "no shrink" grouts out there that I have used in the concrete trade. I've set 50 ton concrete walls on a 2" pad placed on a regular footing. As far as nailing the oak down, we had simular situations. We would drill a 1/4" inch hole and fill in with a 1/4" dowel, mark the hole and then place the wood and nail into the dowel. One trick is to keep the hole at a certain distance (off of the previuos piece) so you dont have to "hunt for it.

If you are stating that one of the 14' long joists has sagged you could do a few things. If it is not load bearing you could cut it and sister in a new straight joist. Not the most fun task but if the goal is to get a dip out I bet it is less work that tearing up the old floor, leveling and trying to install a damaged old floor. All those nails get in the way of flipping a new joist in. I replaced a few joists at a friend's house after a fire. Termites had destroyed a few. Even after the house was gutted from drywall and cabinets flipping a new joist in was a pain. Actually we tore the old carboard joist out and replaced it. If you have seen a termite eaten board they leave nothing but air it seems.

So is this dip in the middle of the 4 foot hallway someplace or is it by a wall where a load was put on a joist where a double or triple joist should have been? Or was it just a joist that went a little wild as it dried out?

I did eng>The foundation has not settled. This is in the main hall about 4ft across &