Why have white tiles turned blue?

tagz

We had our bathroom done about 5 years ago and rather than take the old tiles off the wal,l the tiler fitted the new white ones on top of the old. Now one and a half of the tiles in the bottom corner where they meet the top of the bath have turned blue. They still have white flecks on the them and the whole tile went first before the half tile gradually changed. We haven't used any different cleaners. Any thoughts?

Canucklehead

Hi...copper pipe corrosion (greeny blue colour) is one possibility.

HTH

Canucklehead

ktuludays

the tile is getting saturated with moisture

the grout must have failed somewhere.

allow the tile to dry out then run a thin bead of silicone sealant where you think it will be getting in