Older home (1930’s). Foundation walls in basement had an additonal block wall built in front of original foundation walls that went approx. 3/4 of the way up and had about a 2’ ledge or “shelf” on top of this wall. All of these walls had horizontal cracks at the top course of block below this “shelf” on this “interior” wall, some significant. However, there was little movement, and walls were relatively plumb. Cracks were, in relation to the exterior grade, at or about 1’ below grade. There was minor moisture seepage through masonry at the bottom/efflorescence, typical with age of home (nothing major/out of the ordinary). Exterior conditions were o.k. (e.g. grading, gutters/downspouts, etc.) and the interior showed no signs of foundataion/structural concerns (e.g. plaster cracks, doors & windows, etc.)
Now, what would cause the cracks like this? Any ideas?
Thanks in advance. Any help/insight is always appreciated!