Repairing porcelain tiles

[martibab]

Hello

I have noticed some hairline cracks in my 5-year old porcelain kitchen floor tiles They are laid on a concrete floor. Can anyone suggest a way of repairing them?

Thanks.

Brian

 

[DHTiling]

Big hammer and new tiles

 

[andyb1]

As above.

 

[True Tiling]

Hi Martibab,

Hairline cracks on a concrete floor could suggest that the concrete floor underneath your tiles is unstable and is moving with differences in temperature. Some substrates can crack underneath tiles with movement, and this movement will be reflected in the floor covering (tiles in your case), causing hairline cracks in the tiles. Truly, the only guaranteed solution to this problem is to remove all floor covering (tiles) and isolate the floor using a membrane, and then tile over. The other (non-guaranteed solution) is to take up the tile with cracks in, find the "fault line" in the floor, use a patch repair cement of extremely high strength and then replace the tiles using an elastomeric adhesive and grout. If the cracks in the substrate continues to move in a pronounced way, the tiles will always crack, and the floor is unsuitable to be covered with tiles. Wooden flooring is a better option probably.

 

[Stef]

As said above
We have been back & repaired a floor 5 times now, wasn't us that fitted the tiles originally,
The cracks underneath the tiles on the concrete base are bad & the tiles just keep splitting.
We used Bal single part fast flex (elastomeric) on the last repair & GT1 (again) in the grout but honestly I don't think it will help.
The whole floor has to come up & get relaid on top of an anti-fracture membrane.
The cracks on this concrete base are really bad though.

 

[martibab]

Hi Martibab,

Hairline cracks on a concrete floor could suggest that the concrete floor underneath your tiles is unstable and is moving with differences in temperature. Some substrates can crack underneath tiles with movement, and this movement will be reflected in the floor covering (tiles in your case), causing hairline cracks in the tiles. Truly, the only guaranteed solution to this problem is to remove all floor covering (tiles) and isolate the floor using a membrane, and then tile over. The other (non-guaranteed solution) is to take up the tile with cracks in, find the "fault line" in the floor, use a patch repair cement of extremely high strength and then replace the tiles using an elastomeric adhesive and grout. If the cracks in the substrate continues to move in a pronounced way, the tiles will always crack, and the floor is unsuitable to be covered with tiles. Wooden flooring is a better option probably.

I think the concrete was in pretty good nick before th etiles were laid. I took up the previous Marley tiles myself. I'm mystified, but thanks for the generally good advice.

 

[martibab]

As said above
We have been back & repaired a floor 5 times now, wasn't us that fitted the tiles originally,
The cracks underneath the tiles on the concrete base are bad & the tiles just keep splitting.
We used Bal single part fast flex (elastomeric) on the last repair & GT1 (again) in the grout but honestly I don't think it will help.
The whole floor has to come up & get relaid on top of an anti-fracture membrane.
The cracks on this concrete base are really bad though.

That does sound pretty bad! In reality, I can't even see the (two or three) cracks without getting down on my hands and knees - they really are hairline. Also, the concrete base really did look sound when I took the previous Marley tiles up (no hammering - just lots of scraping!). But thanks for the warnings.