How do I keep the Hairline Cracks in my Ceramic Tiles from Getting Worse?


I just notice some hairline cracks running through a couple of ceramic tiles which are adjacent to each other. There is one hollow sounding tile next to them . The hollow one not cracked yet. I shutter at the idea of replacing this floor. I’m ok with ignoring the hairline cracks because the are hardly visible unless I get on hands and knees to look at cracks. Any advice on what I can do to keep them from getting worse and more noticeable. ??? And what do you feel is going on here. All of other tiles feel solid. Do you think that that 1 hollow tile caused all this. Will I have a bigger problem down the road if I just ignore? Help — don’t know where to turn. Any advice And education truly appreciated Thank u. Jackie


ANSWER - Normally when there are hairline cracks going continuously through a number of tiles including the grout joint, it suggests that there might be a crack i the substrate below it that is telegraphing up through the tile.  The hollow tile might be because there is a void under it or that it isn't bonded.  If the tile wasn't bonded to the substrate you should feel it being loose and the grout surrounding it will be cracked.

There isn't much you can do about it other than replace the tile if you have matching replacements.   The crack could get longer depending on what caused the crack.

23 thoughts on “How do I keep the Hairline Cracks in my Ceramic Tiles from Getting Worse?

  1. Jackie says:

    I’m ok with crack getting longer—-because it’s not noticeable . I can live with that. I AM concerned with it getting wider. Do u think that would happen. All of the tiles fill secure. None are loose So far.

  2. Jackie says:

    The floor is 5 years old. Do you think I will be seeing more hollow tiles in the future or if they were going to happen they would have already happened in more places than just the 2 tiles I have already found. And also—— do the hollow tiles have anything to do with tiles next to them having hairline cracks or do you think the cracks in other tiles just related to a crack in substrate directly below them.

    • Donato Pompo says:

      Whether you get more tiles that become hollow depends on what is causing them to be hollow. Without knowing the cause there is no way to predict the likely outcome. Unless you do the forensic investigation there is no way of knowing if the cracks and hollow tiles are related or independent of each other.

  3. Jackie says:

    Thanks for your patience. As you can probably tell— the last thing I want to do is pull up any tiles. I have decided to live with the hairline cracks for now and see if they get any worse. Do you recommend I fill them with anything like silicon caulk etc. If you do recommend — what product exactly should I use. I see alot of you tube videos recommending different things from silicon to wood glue and then matching paint to put over. Your thoughts on this??? I was thinking to possibly fill to keep moisture out or am I better off just LEAVing them alone right now since that are not noticeable to anyone but me. ???

    • Donato Pompo says:

      If it is a hairline crack I don’t see how you could fill it with anything or any benefit from trying to. If the crack is wide enough you could fill it with a silicone sealant that meets ASTM C920 as it will bond well and be resilient to mitigate and movement within the joint. Although the sealant might pick up dirt over time as people walk over it and it might accentuate the appearance of the crack.

  4. Phyllis Young says:

    We purchased a new home and notice a hairline crack that keeps spreading, which is coming from the outside crack running through the house. And notice several other places within the house with hairline cracks. What is a resolution, any ideas. Or what is a remedy? Any help would be appreciate.

    • Donato Pompo says:

      The only way to understand the cause of the crack and then determine if and how to remediate it is to perform intrusive testing. An expert needs to remove some of the tiles in inspect and document the underlying conditions to look for the evidence of what caused the problem. The crack is simply the symptom of the problem.

      If they cracks continue through multiple tiles and line up with crack in the concrete outside the house then it sounds like reflective cracking in the concrete telegraphing up through the time. But again that is the symptom of the problem. You need to find the cause of the problem so your repair will not reoccur.

  5. Mike Holt says:

    Greetings Donato, Our one story brick home is 8 years old and has a post tension foundation. We have 6 areas in different rooms where hair line cracks range between 4′ and 7′ in length. It’s the tiles that are cracked, there’s no cracks in the grout lines, There is no visible cracks in the walls and none of the doors or trim show any signs of settling. The exterior brick has no visible cracking. We are at a loss as to the cause and don’t want to retile the home not knowing if it will crack again. Any ideas as to the cause and remedy would be greatly appreciated. Thanks

    • Donato Pompo says:

      There are many reasons why a tile will crack. Often when the crack is continuous through multiple tiles they are reflection cracks. There could be cracks in the concrete slab that have telegraphed up through the tile. The installers might have installed the tiles over control joints in the concrete. If it was installed over a backer board then the backer board might not have been installed correctly and the cracks are reflections of the joints in the backer board. There are compression cracks when tiles with excessive voids below the tile are subjected to live loads that causes the cracks.

      The only way to determine the cause of the cracks, so you can make sure they don’t reoccur after fixing them is to remove some of the tiles under various conditions and look for the evidence that shows the cause. This normally requires experts like CTaSC to determine.

  6. Merita Mance says:

    I am having the same issue with hairline cracks all the way over 5 or 6 tiles.
    It happened after an earchquacke.
    What should I do? Should I be worried that the concret below is not safe ?
    please let me know. Realy appreciate it. Thanks

    • Donato Pompo says:

      Cracks might be reflective cracks from the concrete having shrinkage cracks, but that doesn’t mean the concrete slab isn’t safe.

      The only way to determine what has caused the cracking is by carefully removing the cracked tiles and look for evidence. It could be due to how the tile was installed or due to shrinkage cracks in the concrete.

      • Lisa Howes says:

        I just had a slab leak and I don’t recall having any cracks in my porcelain tile. The insurance company sent someone out and stated the cracks are old and the slab leak may have caused them to telegraph up. but it’s not the cause so they are not replacing the tile because they are just hairline cracks. What are your thoughts? It sounds like from what I’m reading, they can’t be sure of the cause without forensic investigating ?


        • Donato Pompo says:

          Normally the insurance company will provide coverage if the tiles were cracked as resultant damages from the water loss event. They will look at the cracks to try to discern if they were pre-existing or caused by the water loss event. Experienced investigators like ourselves can look a cracks and normally can tell if it was pre-existing or not. One clue is whether there is dirt imbedded into the crack indicating it had been there awhile.

          Regardless if whether the cracks pre-existed in the concrete slab, the key is whether the cracks developed as a result of the water loss event.

  7. Simon li says:

    I have vertical hairline cracks in all my 5 bathrooms wall. Some tiles have 2 or 3 vertical hairline cracks in one tiles. Do you think this is a huge foundation problem and what I can do about it. Thank you.

    • Donato Pompo says:

      The vertical hairline cracks could be caused by many things. Normally on a wall it is either due to too much deflection in the wall if it is over a framed wall. If so the spacing between the studs may be too much and it needs bracing or the substrate over the framing isn’t sturdy enough or wasn’t installed correctly. It isn’t likely to have anything to do with the foundation.

      It could also be due to shrinkage cracks in the substrate that are reflecting through the tile. That could be because of shrinkage in the mortar bed if there is one or due to excessively thick thinset adhering the tile that has excessive shrinkage.

      The only way to determine the cause of the cracking, which will then determine how to repair it, is to carefully remove some tiles under various conditions to look for evidence.

    • Maggie C says:

      Honestly, we had large format porcelain tiles on our wall in our master and two cracks were found to be due to foundation issues. I would get it checked to be safe.

      • Donato Pompo says:

        Have cracks in the tile on a wall is unlikely due to foundation issues. If it is a concrete foundation and there was expansive soil or there was settling it would have to be major movement to cause the wall tile to crack. Even if you had a raised wood subfloor with excessive deflection I don’t see how that would cause cracking in the wall.

        I have found that often contractors when confronted with problems will automatically blame it on the foundation or soil to avoid the responsibility for the problem. The only way to determine the true cause of the cracking is to have a tile expert remove the tile carefully to look for the underlying evidence.

  8. Fran says:

    Hello I live in arizona. I had a home built 4.5 years ago. Last Nov I heard a series of loud bangs. My dogs alerted me to where the sound came from and I found cracked tiles in a line from the front to the back of my home. I called my builder and he insisted that it is not foundation. Thoughts?

    • Donato Pompo says:

      Changes are you have a tile floor that doesn’t have any movement joints at the perimeters of the rooms where they butt up to adjacent restraining walls or within the field of tile every 20 to 25 feet in each direction or if near direct outdoor lighting then every 8 to 12 feet in each direction.

      As the tiles heat up or absorb moisture they expand. If there are no movement joints to mitigate this expected stress then it can result in what we call tile tenting. Probably your tiles started tenting and then when the grout gave way it released the stress that resulted in your cracked tiles.

      All you can do it replace those cracked and any loose tile by installing them over a crack isolation membrane and install movement joint as described above per TCNA EJ171 details.

  9. ANNA says:

    Hello, I have a newly construction home and I noticed one crack vertically on the concrete slab outside. So now I see inside my tiles are having cracks in them also like a whole line from one tile to the next. Like 3-5 tiles across. This is all happening on the side of my house which is the kitchen. My hooded vent that was supposedly install and stuck to the ceiling recently came loose on top of the ceiling. Is this a foundation problem? Who do I call? Foundation inspection person?

    • Donato Pompo says:

      I doubt that the hooded vent that came loose has anything to do with the cracks or foundation. More likely the hood was not properly fastened.

      If there are cracks in the concrete slab outside of the house adjacent to where there are cracks in the tile inside the house and running in the same direction, then it is probably reflective cracking. If it is actually a concrete slab control joint, then the installer should have either had a movement joint in the tile over that control joint, or they should have installed a special crack isolation membrane to preview in-plane shrinkage cracking.

      Call the person who installed the hood and call the tile person to fix the tile floor.

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