My neighbors are constructing their house from ground up. We have concrete structures for almost all buildings here. When the walls are ready they need to water it so the concrete settles and get strengthened. This process absorbs a lot of water and thats where Osmosis kicks in with the neighbor's walls (also made of concrete) at the receiving end. So to cut it short all the walls in my house that run parallel to the neighboring newly constructed walls are sucking in water with salt deposits that have ruined the paint as well as making algae thrive over the walls' surface in moist weather.

Now there are cabinets built on these walls which contain everything that needs to be stored, and due to the hassle described above, algae climbs onto everything in its reach (clothes, food, utensils etc.).

Is there any way out of this? I have tried keeping fresh air passage open, but that only slows down the green goo. How to get rid of it and keep it from coming back?

  • This sounds like a real health hazard. Move at least the food to the other side of the room. Move the clothes too; if you have nothing else, stretch a wire between two points and hang your clothes from it. Get lots of fresh air in there. Do not sleep in a room where mould is growing.
    – RedSonja
    Dec 14, 2015 at 12:08
  • Do you currently run a dehumidifier? Dec 14, 2015 at 14:20
  • @RedSonja Thankfully the affected area is not where we would usually sleep, but it definitely is a health hazard and thats why I want to get rid of it.
    – Neoq
    Dec 15, 2015 at 9:13
  • @BrownRedHawk no havent tried that yet. Does it help eliminate mold and seepage deposits on walls as well?
    – Neoq
    Dec 15, 2015 at 9:14
  • 1
    For clarification, are you saying the neighbors are building a pourted concrete wall attached to your house's concrete wall? Where in the world is this happening?
    – DA01
    Dec 16, 2015 at 19:46

1 Answer 1


I don't know what part of the world you're in, but I'm going to figure this might be mold, not algae. Either way, a spray bottle filled with bleach solution will probably get rid of it. Mix a gallon of water and a cup of bleach, and use that mix to fill the spray bottle. Spray it on, wipe it, but don't rinse it off.

Keep in mind bleach is harsh stuff, keep the place well ventilated, use care not to get it on yourself, or anything else besides the wall.

edit: the original poster commented that they were concerned about bleach ruining the paint. This is a valid concern and a good reason to try this in a small and inconspicuous spot before doing the whole wall.

I was curious and found this page


which had some other similar suggestions, along with bleach - ammonia, vinegar, borax, baking soda, hydrogen peroxide, and others. If bleach turns out to harm the paint, maybe one of these would help.

  • But dont you think the bleach will further ruin the pain on the concrete wall? or may even wipe it out completely?
    – Neoq
    Dec 15, 2015 at 9:17
  • That's true - it would be smart to test it first on a small area to see. I don't know how far gone your paint is - it's possible just wiping it will make the paint worse. I'll edit my answer with some ideas that may do less damage. Dec 15, 2015 at 10:29
  • "ammonia, vinegar, borax, baking soda, hydrogen peroxide". Have you been reading my wife's cookbook? Dec 16, 2015 at 19:13
  • 1
    If moisture is already behind the paint, the paint is ruined as it is.
    – DA01
    Dec 16, 2015 at 19:45

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