What might be the cause of the lower level black brick staining, shown on the pictures? What is the remedy? I did not get up close to look at these, rather saw them when I was posting neighborhood notices for an association where I'm the board. These are north facing units that are part of a quad-unit building. I did not look on the south facing units to see if there was similar staining.

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  • With it being beside a garage and running an engine inside is not usually a good idea, wondering if the people warm up vehicles, just outside with exhaust pointed that way. Bare spot on driveway points to this idea, hot vehicle melting snow underneath.
    – crip659
    Commented Feb 17, 2021 at 23:46
  • North side, in the shade, good old natural mold. I would look on the same side of the trees and you can probably find some. VTC as this not about home improvement.
    – Ed Beal
    Commented Feb 18, 2021 at 0:05
  • 2
    I’m voting to close this question because it’s not home improvement.
    – Ed Beal
    Commented Feb 18, 2021 at 0:06
  • Looks like rising damp to me. Garage door indicates it's prone to damp & though you can't always spot a DPC by eye, it would be above the 2nd course on a UK build, so any damp/mould would only go 2 bricks high, not all the way up.
    – Tetsujin
    Commented Feb 18, 2021 at 7:42
  • 1
    Vt Leave open - we have ton of questions about mold, rot & staining, their causes and remediation.
    – FreeMan
    Commented Feb 18, 2021 at 14:47

1 Answer 1


Looks like mold/mildew due to rain splash from lack of (or clogged) gutters.

Generally, the staining is not uniform from top to bottom.

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