Blotches / Stains / Dark Patches appearing on White Tiles?

[Arsene]

Hi

I have noticed dark patches appearing on some of the white tiles in my shower / bathroom. The patches appear blueish/purpleish and are quite noticeable. Just wondering what the cause of this is likely to be, and what can be done to remediate? My initial thoughts are that there is water behind the tile (possibly from decayed grouting) but have never come across this before.

Any ideas welcome.

Thanks

 

[Qwerty]

It does kind of look thst way! On your bath too!!??

 

[Arsene]

No stains on the bath (might be a shadow that looks like a stain). So you reckon water is getting behind the tiles causing the discolouration?
Cheers

 

[Flintstone]

Strangely I have seen the exact same thing today for the first time in a shower, I’ll post a photo tomorrow. Exactly the same

 

[Qwerty]

From experience I have seen it before when mould had formed behind tiles where grout failed and it was very wet on plasterboard.

Do you have plastered or plasterboard walls?

 

[Arsene]

Thanks, yes its plasterboard. I tend to agree with you, I have to say the grouting job is pretty shoddy and some rot on adjacent wooden frame supporting shower. Never seen it before though! Thanks for your help

 

[Flintstone]

Here’s the one I’ve seen

 

[Qwerty]

That is almost certainly water. You can see where it is 'framing' the tile!