Efflorescence

[Gazzer]

Still havent answered if walls were painted ?
Did you use a new sponge ? see a few times when colour came out of spponge but then you should have noticed that when washing off.

 

[DHTiling]

So it shouldn't be a moisture problem..

You need to call weber and get a Rep out....before you do anything else..

 

[chelsway]

As i remember i think the walls were painted but around the shower area it was old unpainted plaster,one wall had been wall papered and paper removed.

 

[chelsway]

SO IT DOESNT SOUND LIKE A Efflorescence to you?

 

[DHTiling]

Efflorescence is salts and not yellowing.

 

[chelsway]

the sponge is nearly 2 years old and have never had any problems with it

 

[Gazzer]

SO IT DOESNT SOUND LIKE A Efflorescence to you?

Nope, some form of contamination. Either from the substrate, the grout itself or maybe they have been cleaned with something after grouted by client.
If it is 100% discoloured i would rule out the client as you usually miss unseen areas when cleaning.
Could be bad batch of grout ?

 

[Gazzer]

the sponge is nearly 2 years old and have never had any problems with it

:yikes::yikes::yikes::yikes::yikes: i wish i could get 2 weeks out of my sponges ??????

You sure its not rust 😉

 

[DHTiling]

2 years old....:lol:....well there you go..

 

[chelsway]

2 years old yeah but only used about 30 times!.