shower leaking behind wall

[dan_the_plumber]

Hello all.

I have a problem with a shower.

The tiles behind the shower all blew

Customer had them taken off and retiled.

Then they blew again and there was a discolouration of the ceiling in the kitchen below

Customer had tiles replaced a second time.

Then I was called in, I ran shower with cover off and found samll leak inside the shower which i PTFE taped which fixed the problem in the shower.

The wall was then retiled by the tiler.

I then camed back fully sealed where the electrical cable come through the wall with silicon.

I also covered the back of the shower unit in silicon and screwed back to the wall

All the tiles have now blown again!!!

I'm at a loss......Anyone suggest what the problem might be please?

Dan 🙂

 

[spanner]

Yes correct...a chemical reaction, where the pipe turns green (patina)