Hairline cracks in tiles

[PPM]

Can anyone help? I have surveyed a job in a local gym, there are a number of tiles in the showers that have hairline cracks running through them. The grout line between the tiles is very small (1mm). What would cause the hairline cracks? Would it be possible take out the grout and regrout without damaging tiles? Would a tile on tile option be suitable for such a humid area?

 

[paulmsd]

tiles don't crack on there own there is obviously a problem behind the tiles

re grouting the cracked grout joints won't solve anything that will just hide the real problem

 

[Turkish]

Maybe water ingress expanding the substrate behind if timber. Not much of a grout joint either, personally i wouldn`t like to go smaller than 3mm. Regrouting that small a grout line will be next to impossible i feel without damaging the other tiles and as already said a waste of time as you wouldn`t be solving an existing problem.

Turkish

 

[DHTiling]

You need to find out the cause of the problem first.....

1. how big is the floor area and what is the longest run of tiles.?
2. are there any expansions joints or perimeter joints.?
3. what type of substrate is it.?
4. A photo of the affected area would be good...