Should I be concerned about 2 Hollow Sounding Tiles?

QUESTION

We had our small kitchen concrete floor area fitted with large porcelain tiles in late November 2016, replacing the original glass tiles which had broken over the years
The company is reputable and registered and had fitted our bathroom in 2008 with no issues so we were confident of an equally professional job on the kitchen floor.

2 of the tiles now have a hollow sound if you tap on them compared to the rest. The grout is intact and there is no movement. The only issue so far is the sound. We are unsure how long this has been the case as we wear soft shoes indoors and it only became apparent when my son walked into the kitchen in his work shoes.
I rang the tiler and expressed my unease and asked him to come and check it out. I felt that he was unconcerned that there is a problem. He asked if I wanted the tiles lifted and re-fitted and said it would be a "messy job"
I said I was concerned about it but trust him and would be guided by his professional opinion. He said it was "just an air pocket" but agreed to call to the house next week to see it. He asked if the grout was still intact and if there was any movement. When I said there wasn't, he said it was simply an air pocket and was probably there from the start and he had seen that happen before many times.

I have searched for information on Google and I am of the belief that the affected tiles would be compromised should something fall on them. I am also convinced by various reports I have read, that these tiles were applied with the method of spot adhesive at the four corners and the centre and not on the entire tile area and that there are voids where the tiles are not making full contact with the mortar underneath.
I would welcome your observations in the matter or your assurance that the tiler is right and that there is no cause for concern. We would feel more equipped to put my case to him when he arrives, if I have some expert opinions.
I understand that any reply is merely an opinion and that I will need to deal with the matter when he comes out.
I know that we are covered legally by the Sales of Goods and Services Act but I am hoping for a favourable outcome without having to resort to litigation
Many thanks for your assistance

ANSWER

ANSWER - According to industry standards having hollow sounding tile is not a defect in itself.  Although a hollow sounding tile can be a symptom of a defect.


A tile having a hollow sound could be an indication that there is a void under those hollow sounding spots and/or the tile isn't bonded at those hollow sounding spots.  A hollow sound can be caused by the configuration of the tile assembly, it could be the result of having some sort of membrane under the tile.  It could be an indication that the underlying substrate has a condition that is causing the hollow sound.  The only way to determine what is causing the hollow sound is to carefully remove the tile and evaluate the underlying conditions.


If the hollow sound is the result of having a void under the tile that is larger than 2 square inches (about the size of a golf ball), then the tile could be susceptible to being damaged if a hard sharp object fell on that spot.  Residential floor tiles can have up to 20% voids as long as the voids are dispersed and not larger than 2 square inches, and that the corners and edges of the tile are adequately supported.


If only two tiles out of many sound hollow, then I would not expect that all tiles were installed in a spot bonded method.  If the grout joints are not cracked around the tile, then the tile is not likely loose.  It is not that difficult for a professional tile installer to replace two tiles.  Having a wet and dry vacuum and taking some simple precautions for dust control, it can be done within a couple of hours.  So if the 2 hollow sounding  tiles bother you, then you should consider having the installer replace them.

21 thoughts on “Should I be concerned about 2 Hollow Sounding Tiles?

  1. Anne Beirne says:

    Dear Donato

    Thank you so very much for your email . We are indebted to you for your comprehensive reply.
    Everything you wrote and advised makes sense .

    As you pointed out, any considerable void under the affected tiles could potentially cause problems should any weight be placed on them . We are planning to change our carpet next year and we are concerned that the weight of the furniture placed on the affected tiles during the fitting could cause them to crack or break . There is definitely more than a golf ball size void on the affected tiles .

    I am pleased to read that there is no assumption that all of the other tiles were adhered with the spot method so we are hoping that this matter can be rectified with our tiler as you described

    We will ask that the two tiles be lifted and re-fitted. We are so pleased to have the advantage of your timely advice on time for his inspection.

    Thank you Donato. We will let you know the outcome
    This is a truly wonderful service to ordinary people like us who accessed your website while searching hopefully for some advice .
    With warm regards
    Anne Beirne

  2. Donato Pompo says:

    The standards don’t recognize hollow sounding tile as a defect. Tiles can sound hollow because of what it is bonded over and to what it is bonded.

    If the hollow sound is proved to be voids under the tile, then for interior wet areas and exterior areas there should not be any more voids than 5% of the surface area. No void should be larger than 2 sq. inches, and all edges and corners of the tile should be fully supported.

    For residential interior dry areas you can have up to 20% voids under each tile, but all corners and edges are to be fully supported.

  3. Mick says:

    I have 1 hollow tile 600x 300 in my corner shower floor only been layed 4 weeks ago should it be repaired by the tiler at no charge ?

    • Donato Pompo says:

      Per the industry standards hollow sounding tiles per se are not considered a defect. A hollow sound can be a symptom of a defect, but there can be hollow sounds that are not defects.

      The hollow sound might be a reflection of the condition of the substrate beneath the tile. It could be from a void under the tile that is within allowable tolerances.

      If the tile in your shower is entirely hollow then I would expect it to be loose. If the tile is loose, then I would expect the grout joints to be cracked and the tile will move to some degree. On the other hand, the might be partially hollow because of an excessively large void. The standards say that for a shower application there should be at least 95% adhesive contact between the tile and its substrate. The 5% voids should be dispersed.

      A partially hollow sounding tile can be well bonded. If it has an excessively large portion of the tile with a void, then if something heavy impacts the portion of the tile where there is a void, then it can have a propensity to crack at that spot.

      If you replace the one tile then you have to have a matching replacement that blends in with the other tiles. The grout color will not match at first, even if you have the same grout left over, as it will dry differently and be new that results in a different color. Over tile as it gets soiled it will likely blend in.

    • Donato Pompo says:

      If you mean that there is one tile that is hollow sounding, then yes I would expect the installer should replace it at no charge.

  4. Anthony Houghton says:

    We have been in our new home for a year now. We have so many hollow sounding tile full 24 x 24 . The builder came out once and replaced 23 and found that they were put down with mastic. Now there telling us the industires standard allows for 65% of the tile to be hollow , so they wont fix our floor. I thought the standard was 20%.

    • Donato Pompo says:

      The industry standard for tiles installed in dry interior applications is that it has to have at least 80% continuous contact between the back of the tile and its substrate. The 20% of voids allowed have to be dispersed and no void should be larger than 2 square inches. All corners and edges of the tile have to be fully supported.

      The ANSI A108.5 standard does not mention hollow sounds because hollow sounds can be due to voids or due to other underlying conditions. The only way to determine if the tiles were installed with excessive voids is to remove some and document the underlying conditions.

  5. Mariam Noujaim says:

    Resurfacing my swimming pool with ceramic title to cover the ‘infinity edge’. The edge is 2 equal lines covered with ceramic tiles. The first 3 tiles on both rows (total 6 tiles) are very very hollow; the rest is fine. I brought it up to his attention; but he said it was nothing…?!!!
    Your thoughts?

    Thanking you in anticipation

    • Donato Pompo says:

      A hollow condition doesn’t automatically make it a defect, but often it is a symptom of a defect. That fact that some tiles sound solid and some sound hollow could be suspect, unless the underlying substrate is causing the hollow sound. If there is a pipe or a filter opening under those tiles it could cause a hollow sound. If all tiles are installed over the same substrate that has the same underlying configuration and materials, then I would want to remove a hollow sounding tile to determine if there are excessive voids or if it appears to be well attached. It normally isn’t that much work to remove and replace a tile for a qualified tile installer.

  6. Marisa says:

    Sounds like elephants and hammering above new apartment. They say a 2 year old running. 4 days a week and can’t stop them
    Any ideas
    I have many hollow tiles. And assume they do also mine some . Moves and. Makes a sound

    • Donato Pompo says:

      There are sound control systems that are installed with the tile, but obviously it is too late in your case. Also it is possible to fill the floor cavity between your ceiling and the apartment floor above with an acoustical foam to help deaden the sound.

      Tile can sound hollow depending on how they are installed. Sometimes it is a symptom of a defect in how they were installed. If the tile moves then that is a problem as they should not move.

  7. Andrew says:

    Where can I find the information that states how much area can be hollow, that there cant be more than 2 square inches of void, and that all edges and corners need to be firmly bonded?
    I have been fighting with a tile setting company who Supposedly follows all code and standards for over a month since I stopped them from working. I stopped them when i noticed a bunch of problems with what i have read and learned.
    I had 12 x 24 porcelain tiles installed and I have hundreds of tiles with edges and corners voided along the entire long edge. Many of them are up to 2 inches under the tiles and run 50 to 80% the length of the tile. You can tap on the tiles and the one edge is obviously hollow over the rest of the tile.
    I stopped them before they grouted and can actually shine a flashlight and see all the voids under the same edge on those 100+ tiles. I bent a paperclip and am able to stick it under most of those tiles about an inch and run it the length of the tile.
    They keep giving me the runaround and telling me I am just being picky. They said the grout would fill those voids.
    I contacted the AZ roc and will have them out to inspect the project, but I cant find this specific info about hollowness on their site and would like to be able to show it to them.
    Thank you in advance for any and all info you can give me.

    • Donato Pompo says:

      For 12×24 inch porcelain tiles in an interior dry area application, the industry standard ANSI A108.5 states that the tiles should have a minimum of 80% coverage that shall be sufficiently distributed to give full support to the tile with particular attention to the support under all corners of the tile.

      The TCNA 2021 Handbook says Average contact area for dry areas is 80% . Mortar coverage is to be evenly distributed to support edges and corners.

      We do have an inspector in Arizona as well and inspections there. Go to http://www.CTaSC.com for more info.

  8. Darren B says:

    Hi Donato,

    Do you know of any tests or recommendations for sand seed the last coat of an acrylic waterproof membrane before applying a sand/cement screed? The waterproofer did not sand seed the membrane as there was no requirement in the manufacturer’s literature; however, the owner, on completion of the tiling, said the tiles sound drummy in all 5 wet areas and is blain the waterproofer for not sand seeding. I understand that drumminess is not a defect unless there is movement.

    I would appreciate it if you could point me in the direction of any literature that agrees or disagrees with sand seeding.

    Thanks

    Darren

    • Donato Pompo says:

      Regular liquid applied waterproof/crack isolation membranes that meet ANSI A118.10 and A118.12 are a latex based membrane that can be an acrylic based product as an acrylic is a latex. These products do not require sand seeding. You can bond the tile directly to the membrane.

      Only epoxy or urethane based vapor barriers or waterproof membranes require a sand seeding in order to have a tile bond directly to it with a polymer modified thin-set mortar that meets ANSI A118.4 or ANSI A118.15.

      The TCNA handbook states that sometimes when tiles are installed over a membrane it can give a hollow sound. If the hollow sound is uniform throughout then it may be the membrane causing it. Although sometimes hollow sounds can indicate excessive voids under the tile or that the tile is not bonded. If the tile is not bonded then normally the grout will crack.

  9. Zacc says:

    I had about 20 ceramic tiles (10 in each row) (dimension: 300×300) that pop up last night. Do you think Fix-A-Floor would help to stop my other ceramic floor tile (living room) from popping up?
    Pop up due to hollow tiles and changes in weather.
    Thanks!

    • Donato Pompo says:

      If your tiles popped up, what we call tented, then the problem is that the tile floor has expanded, but it is constrained, so the only way to release that tension is to lift up. This could be due to the weather where you have more rain and humidity, where the tiles absorb moisture and expand.

      By those tiles coming loose may have relieved the stress in the other tiles. So the problem might not be that you have voids under the tile and that you need to try to inject Fix-A-Floor under the tiles through the grout joint.

      You may just need to add some movement joints at the perimeters where the tile butts up to a wall or within the field of tile every 20-25 feet for interior applications if there is no direct lighting, and if there is direct lighting then every 8 to 12 feet in each direction.

      A movement joint is either a open gap between the wall and tile that can be covered with a base or filled in with an ASTM C920 sealant caulking. Movement joints in the field of tile is the ASTM C920 traffic grade sealant caulking to fill in between tiles in lieu of a cementitious grout.

      The only way to determine what your condition is, is to remove some of the tiles in various conditions to see what underlying evidence there is to explain the resultant damages.

  10. Deborah J Rowe says:

    Have about 8 tiles sound hollow. Only have 4 replacement. Should we try something like fix a floor? Concerned as we have limited tiles throughtout. Plank type tiles (which resemble wood).

    Also, what type of contractors/handyman would I hire to do this?
    The grout is intact for 6 tiles. Noticing not intact for 2 hollow tiles

    • Donato Pompo says:

      Just because the tiles sound hollow doesn’t mean they are not adequately installed. It can me a symptom of problem or that they didn’t install the tiles per industry standards to get at least 80% dispersed contact and full support along the tile edges and corners.

      The fact that the grout is cracked at the two hollow tiles, might be an indication that they are loose and you should replace them. That will give you an idea of how the tile was installed and help you determine whether to remove the other tiles.

      Always best to hire a full time tile installer since they have the experience and are less likely to damage the adjacent tiles to the tiles that are removed. Although often licensed tile installers don’t like fixing someone else’s work as it could become a problem for them.

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