www.ultimatehandyman.co.uk

Hi, I have this strange white 'stuff????' appearing on my wall. It is on the inside of an exterior wall which is made of stone ( not sure if this is relevant) it's an upstairs room so not sure about damp. The wall is well pointed and i do not think there is water coming through. i always thought that mould showed black but this is most definitely white.i have tried washing the wall with a bleach solution and also with household detergent but as soon as the wall dries the white comes back. I know i've waffled but hey! any ideas folks!

sorry, no idea what the fix is for this, but you would probably be better off posting the question in general diy.

No need to post in several forums Flatpack

Wonder if it is distemper?

the painters and decorators will know

Sounds like efflorescance, and wetting it makes it worse let it dry and brush off with a stiff broom NOT wire brush you may have to do this several times and there is no real cure for this. It's just the sulphates and salt in the stone being drawn out to the surface, and don't worry it's not damaging