Our block foundation has some spalling just above grade and an outside corner with additional damage just below the grade (see first photo). The downspout extension in this corner had been leaking water behind it with the previous owner (I suspect for quite a while).

Here's what we're seeing on this end of the house:
- Spalling above grade
- Horizontal cracks along joints
- Significant deterioration at corner, below grade
- This end of the house is vented crawlspace

Items we have done or plan to address:
- Achieve negative grade away from house
- Downspout extensions (5' long) no longer leak against house

I suspect the deteriorated corner is from the downspout extension leaking against the foundation for an extended period. Is it bad enough to require repair? Can it be cleaned and patched, or does the block need replaced?

What about the spalling above grade? Is there something we need to do with it?