Basement foundation cracks

[Joshua L. Frederick]

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!

[Joshua L. Frederick]

O.K., maybe I'll simplify things a bit. What causes horizontal cracks high on a basement wall?

[Joshua L. Frederick]

Having difficulty sorting through all the replies.... I guess there must be some good football game on.

[Wayne B. Wilson]

It appears that it was a crawl space made to a basement, I would say just the inward pressure behind the wall is causing it. Was there any bowing or water issues?
Joshua if you want want replies add politics or religion in your post .
Something like this (The foundation of our country is crumbing .) lolol

[Wayne B. Wilson]

Did the inside wall Have a footing or did they just use the slab?

[James E. Braun, CMI]

This type of foundation is very common in my area. There is usually no footing under the outer wall. The inner wall just holds the soil in place under the outerwall. It will slowly get worse but it would take longer than my lifetime to see a complete failure. I have seen these inner walls lean in a good 30 degrees all ready without failing. I just note it and move one.

[Marcel R. Cyr]

Originally Posted by jfrederick

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!

I think Wayne was on the right course of questions on this one.
1930's home most likely had a stone foundation with either brick at the top two feet or all stone.
The unbalanced fill on the wall might have been too much and over the years started to give way to the interior or deteriorated to the point of collapes, why else would they build a new block wall on the interior that don't seem to support anything above that I can see?

Unless you can verify what is going on behind the block wall that caused this inward pressure to create that crack, I would defer it in a heartbeat to an engineer or Architect.

[Wayne B. Wilson]

Yep Marcel
I have seen this several times down here