Sometimes it is worthwhile scrapping back to original brick, treating with Coprox into plastering mix when plastering is done. Normally need someone with the knowledge on doing this, like icing a cake.
Have resorted to using Mould Buster sold at certain hardware stores, or Makro, works reasonably well. Tried spirit vinegar with little lasting affect on a wall that really pissed me off, eventually took it down to the bricks and did first suggestion.
Mold that seeps up through the bricks may be structural, on-going nightmare we suffer on clay.
The spirit vinegar seems to be holding up pretty well, although as I said, our bedroom smells like a fish and chip shop for a day or two but it does work. I found a mold buster at Pick n Pay many years ago and although it did the job, the stuff was horribly toxic. I remember it falling into my eyes as I did the ceilings with a broom and not being able to breathe.
Mold Buster spray and run, very toxic. Found the vinegar did not work here. Well hope it clears up soon π
right? mold is a terrible thing. It can also be as toxic as the things we fight it with. For now, the vinegar seems to be holding steady and will improve as we head into warmer months. Perhaps once we have managed to get it under control and summer hits, we can repaint with an anti-mold paint.