Floors do not sag on their own. Something under them gave.

Sagging Floors: diagnosed and explained.

A sagging floor starts subtle. Furniture rocks slightly on legs that used to sit flat. A marble rolls toward the middle of the room. The floor bounces near the bed, or a hallway develops a dip you feel in your feet before you ever see it. Under a raised foundation home, all of that traces to the support system in the crawl space: wood posts standing on concrete pads or piers, carrying girder beams, which carry the joists and the floor you walk on. When any link in that chain weakens, the floor above it drops. The two usual culprits in our region are moisture and soil. Water from poor drainage keeps the crawl space damp, and damp wood posts rot from the bottom up until they crush or lean. Meanwhile the clay soil under the piers acts like a sponge, swelling when wet and shrinking when dry, so the supports sink and tilt a little more with each cycle. Some older homes add a third cause: supports spaced too far apart for the loads they carry, so girders deflect between them. Whatever the mix, sagging floors do not recover on their own, and the framing keeps adapting to the sag the longer it stands. What happens next depends on what failed below. Supports that settled or rotted are lifted back toward level with adjustable steel support jacks on stable footings, damaged posts and girders are repaired under our structural repair service, and the moisture that caused the damage gets corrected in the same project. Homes on raised foundations with widespread slope are covered on the pier and beam repair page. The first step is measurement: an elevation survey that maps exactly where the floor sits and which supports moved.

For the repair side of this, the crawl space repair solutions page lists every method Dalinghaus installs, including the ones that fix problems other than sagging floors.