What is this? Some kind of Rot or Fungus?

5 Aug 2023
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United Kingdom
Hi I have this seeping out of brick/cement plastered walls in my holiday home in sunnier climates.

Does anyone know what it is?

What is the treatment?



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Include something to show scale.

You say it is a wall. Is the wall made of concrete?

Show us the other side. Include all cracks, damage, fixings, pipes and drains

And the roof, gutter and pipes above.

What country is it in?
If it wasn't for the top bit, I'd say South America on a cloudy day.
Another pic attached showing the wall behind a dressing table. The wall is made of brick with a cement render which was then painted using water based emulsion paint.

It is a first floor room there is no drains or pipes on the other side although it is a gable wall. The apartment is in Lahore, Pakistan which has very hot summers and little rainfall in the year and is not located near the sea.

If I were to bring back a sample of the white growth is there somewhere in the UK I could get it analysed?


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OK, don't provide the scale, and don't photograph the other side of the wall, then.
I am not at the property which is overseas so can't measure it or provide the photo on the other side at the moment.
Going by the colour, it doesn't look like rot or fungus to me. I'd guess it's the result of a chemical reaction between the top layer and the substrate, possibly assisted by moisture.
It just looks like something water-soluble that's crystallising. It's getting wet, wicking out then drying, leaving whatever's dissolved behind.

Some call it "salts". It's basically any mineral, from the cement, concrete or plaster. But it indicates damp, water is carrying and depositing it.
The shape looks to me like a crack in the wall, with damp creeping through it.

I wonder how big it is.
The shape looks to me like a crack in the wall, with damp creeping through it.

I wonder how big it is.
I wonder what's on the other side of the wall?

Seriously, I think Ivor has it right. Looks like salt crystals.

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