Which way the floor slopes is diagnostic, and it is one of the most useful things a homeowner can notice.
Toward the Middle Means Look Underneath
If the floor falls toward the center of the house rather than toward an outside wall, the problem is almost certainly under the floor rather than around the perimeter.
In a pier-and-beam house — which covers most older Birmingham neighborhoods, including Homewood, Bessemer and the older parts of Irondale and Leeds — the outside walls sit on a continuous foundation, while the middle of the house is carried by a girder running down the center, supported by a line of interior piers.
Those interior piers are frequently the weakest part of the whole structure. Many were dry-stacked masonry with no mortar, set on inadequate footings or none at all, with wooden shims on top to make up height. The shims rot or crush. The piers settle into clay that softens when it gets wet. The girder drops, and the floor above it drops with it.
Why That Is Good News
Perimeter underpinning with steel piers is a major job. Rebuilding interior crawl space support is not. New footings sized properly, adjustable steel jacks or new piers, steel shims instead of wood, and sistering any girders or joists that have softened — it is a fraction of the cost, and it is what a large number of these houses actually need.
If a contractor looks at a floor sloping toward the center of an older Birmingham home and quotes perimeter piering, ask them to explain why, because that is not usually where the failure is.
Toward an Outside Wall Means Something Else
A floor falling toward an exterior wall points to perimeter settlement instead, and that is where piers come in. Check outside for stair-step cracking in the brick along that wall and for diagonal cracks above nearby windows.
Springy Is Different From Sloping
A floor that bounces underfoot without necessarily sloping is usually a joist problem — undersized, over-spanned, or weakened by moisture or termites — rather than a pier problem. The repair is sistering or adding intermediate support, not lifting.
What to Check Yourself
Put a marble down in several rooms and see which way it runs, and note whether the slope is consistent across the whole house or confined to one area. Then, if you can safely get into the crawl space, photograph the center girder line and the piers under it. Leaning piers, fallen shims and a visibly sagging girder are usually obvious in a photograph, and they answer the question before anyone visits.