new tiles with white grout, have yellow staining in random places - Tile Advice

[tile89]

Hi there
Have been tiling for 4- 5 years now
Always used bal bucket adheshive (green or white star) for walls and Ardex grout
A while ago i had a job where there was white tiles with white ardex grout and yellow staining apeared (the next day after grouting) in a few areas, (this wasnt major as it was only me who picked up on it,) i scraped back re grouted and havent heard anything back so guess its fine.
I have just finished a job with same application, and the same thing has happened
I thought it could have been the yellow from sponges maybe bleeding through, but i used nicobond sponges on recent job and tilesources sponges on other job.
Also thought it could be colour in the wall bleeding through but there was slight discolouring on a brand new plasterboard wall i had built.
I used profix waterprooftanking behind tiles and there seemed to be a bit of staining here aswell.

I thoroughly clean out my grouting buckets, before grouting and floats, (i have seperate buckets just for white grout) and i always use new sponges on each job.

i have heard certain adheshive if not set can react with certain grouts, but i have used this combination before and only had the trouble on these 2 jobs

Any advice would be much appreciated
Thanks

 

[Rookery]

How soon did you grout after fixing?

 

[DHTiling]

Hi... This is due to grouting before the dispersion adhesive has dried, thus the moisture from the dispersion adhesive is leaching through the now grouted joints.

 

[tile89]

prob about 24 hours, u reckon the adhesive could be reacting with grout?

 

[DHTiling]

prob about 24 hours, u reckon the adhesive could be reacting with grout?

No, the adhesive is not dry and moisture from the adhesive is staining the grout...

 

[Rookery]

And how big are the tiles?

 

[tile89]

And how big are the tiles?

about 250 x 400 why ?

 

[Ian]

about 250 x 400 why ?

Dispersion adhesive is not recommended for tiles over 300x300, as the adhesive in the middle of the tile will struggle to get any air to enable it to dry out.