Any bowing you can see means the wall has moved. The question is how much, because that decides how it can be fixed.
How to check it yourself
- Level. Hold a 4-foot level against the wall vertically at a few spots. A gap in the middle, or a gap at the top or bottom, means the wall is bowing or leaning.
- String line. Stretch a string tight along the wall from corner to corner, a few inches out. Measure from the string to the wall at the ends and in the middle. A smaller gap in the middle means the wall bulges in.
- Write it down with the date, and measure the same spots again in a few months.
What the movement means for the repair
There is no single cutoff for every wall. Each carbon fiber, brace and anchor system has its own limits set by the manufacturer, and a contractor measures the wall against them. In general:
- Small movement in a solid wall can often be held with carbon fiber straps.
- More movement usually needs steel I-beam braces or wall anchors.
- A lot of movement, a wall that is crumbling, or one that has slid at the bottom, usually has to be dug out and rebuilt.
The longer a wall keeps moving, the further down that list it goes.
When to call right away
- The wall is moving quickly, or a crack is opening month to month.
- Blocks are cracking through, not just along the mortar.
- The bottom of the wall has slid in.
- Doors upstairs started sticking at the same time.
See all the options on bowing basement walls.