u/SubstantialBuy1664

Hi All,

Firstly, apologies if this is not the right place to ask this question. I wasn't sure where best to take it.

I live on the top floor of a c.1970's two floor block of flats. I've noticed recently that this chalky white residue has begun to develop on the inner brickwork of my north facing balcony. It start off on just a couple of bricks but seems to be slowly spreading.

Does anyone know what this residue might be, if it's any cause for concern, and how best to manage/remove it?

Thanks