I am in the Early stages of a Kitchen Face Lift, Its not a Complete tear out, But I do have a problem with my Floor, as it Sloops about 3.5" in an 8' area? I can get under the Kitchen Floor, I was woundering if I could Pour a Concret pad, and then use a Jack or post that would stay put? Or what are your Ideas.
Post some picture so we can see what your seeing under there.
Going to need several footings and a beam (doubled up 2 X 8's or 10"s) to span the whole area.
That's a huge drop so before doing anything I would be trying to figuure out what caused it.
Sunken old footings, insect damage, fungus, under sized and to long a span on the floor joist, failing main beam ECT.