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Laying ceramic tiles over remmnants of contact cement

Dafna Kremer
January 22, 2019

We are in the middle of a large renovation project and are finally ready to lay ceramic tiles. Two of the rooms have remmnants of contact cement on the current floor. Do we need to remove this before before glueing on the new ceramic tiles?

Comments (25)

  • cat_ky

    You do, if you want good adhesion on your new tiles and want them to lay flat. What is your current floor made of?

  • Mr. Memes
    My question besides what you already have down as a subfloor is what do you mean glue down tiles?
  • Dafna Kremer

    We live in a mediterranean country where all floors are generally ceramic tiles. They are glued in place normally on a subfloor of cement but many remodels mean gluing new tiles over old.

    In this instance we will be glueing ceramic tiles over an area where we removed parket flooring which was laid over the original tile floor. When we removed the parket there was a layer of contact cement that stuck to the old tile. It's not everywhere but there is a film in many places.


  • Mr. Memes
    Well if you have every thing up and left with the original concrete floor then you can either grind the left over patches down to a consistent smooth surface. Or you can add a concrete leveler this can be done with thinset or concrete mixed very wet, this well cover the residue left over. Then once dried you can tile.
  • PRO
    The Kitchen Abode Ltd.

    It is difficult to make a proper recommendation due to the fact that it is not clear, maybe a terminology thing, as to exactly what residual product remains on the existing concrete. If it is actually "contact cement" then that will most likely need to be removed as it will impede the ability of most other tile setting materials from forming a proper bond. This would also be applicable if you just try to go over it with, what some have suggested, a watered down thinset or concrete. The contact cement will impede the bond and by over diluting the thinset or concrete you will have also undermined those products performance and certainly voided any warranty.


    There are specifically formulated products referred to as self-leveling cements. These cementitious based products however are also limited by the type of substrate that they will properly adhere to, you would need to check with the manufacturer. Also most of these require the application of a bonding agent to the existing substrate prior to the application of the self-leveling cement.

  • PRO
    Retro Steam Works

    I'd recommend to remove all old glue/cement before tiling over it; it takes time and effort but is better than having loose tiles in the future...

  • SJ McCarthy

    Do you mean "mortar" the tiles into place? Or are you using and actual "glue"? And when you say the old parquet was glued to the old tiles, what type of tiles are the original?

    Can you send photos of what you are trying to describe? I think we are getting a bit messed up with your use of the word "glue".

    And I second the idea of :remove all the old and get down to the original subfloor. Laying porcelain tile over old porcelain/ceramic tile is a difficult enough job. Laying new porcelain over CONTAMINATED old porcelain = really bad idea that can go wrong in so many ways that it would make your head spin.

    But first...how about some photos so everyone can get on the same page with what is already there and what you are trying to put over top.

  • Corrector

    "Or you can add a concrete leveler this can be done with thinset or concrete mixed very wet,"

    " this well cover the residue left over"

    More bad advice.

    Thinset is not to be mixed any wetter than the MFG spec sheet allows..Also not to be used to encapsulate glues or spalled/failed concrete as a patch. That is a sure way to a bond failure and future issues.. NTCA is working hard to educate the pubilc, DIYers and tradespeople that dont follow standards as to the proper use of thinset via ANSI and MFG instructions/standards..

    Thinset is used only to bond A tile to the proper substrate and adhere membranes. Always within MFG directions ANSI and TCNA standards. . Unless you are a risk taker, If you are A DIY-er no reason to skip proper methods and material applications unless you want to.


  • Mr. Memes
    Oh please! Stop hiding being what's on paper in your silly tcna handbook and actually do some tile installations. #therealworld!
  • PRO
    The Kitchen Abode Ltd.

    "Oh please! Stop hiding being what's on paper"


    No one is hiding. The facts stated by accredited associations such as NTCA are backed up by extensive product/system testing and evaluation of current and historical real world performance. This should not be taken lightly or ridiculed.


    Major manufacturers expend considerable time, monies and effort in the development of their products to ensure they will perform as stated when properly installed. They have much better things to do with their resources than fighting law suits.


    One can always take a very cynical position concerning their efforts but I can assure you that the majority of the involved persons are only concerned about providing users with the best available and substantiated information and guidance as possible.

  • Mr. Memes
    I have read the tcna guildlines read the books been on forums across the web. Installed hundreds of tile floors and walls. I can tell you the real word trade of tiling will never match what's in the handbooks. I know what works. I know what doesn't work. I know I can void warrentys and Know I will not get a call back.
    Every tiler does this trade differently. The reason I'm here is to tell you that selling tile out of a store or being a tcna rep does not make you a tiler installer.
    You can not expect to tell me The guildlines of any tile handbook but not the person doing the diy install. You can not learn tiling with out doing it more then 30times.
  • Corrector

    " I can tell you the real word trade of tiling will never match what's in the handbooks. I know what works. I know what doesn't work. "


    Simply not true.


    The NTCA is working very hard to educate the public, the DIY set and the cut corner tiler of proper APPROVED methods of tiling as well as product use with both MFG installation and ANSI specifications and TCNA methods..


    Unfortunately there are A lot of amatuers trying to ruin the tile trade out of shear disregard for the very standards that are in place for just this reason.


    Lets make tiling A respected trade again by doing things properly..

  • Mr. Memes
    Looks like we can agree to disagree.
  • PRO
    The Kitchen Abode Ltd.

    "Looks like we can agree to disagree"


    That has nothing to do with the premise of these discussion. Believing in something does not in itself make that belief factual no matter how many times it's perpetuated or how strongly the believer believes in it.


    That statement is typical when one can not substantiate or at least provide a reasonable explanation for their particular position. Just blanket trashing the NTCA without providing any supportive reasoning for doing so, other than broad generalities, is unethical and it undermines the credibility of the one doing so.


    No one says one must agree with everything, but a professional when disagreeing will always provide a respectful and reasonably detailed explanation to enable others to potentially understand the their position.

  • Mr. Memes
    SMH.... When do kitchen design people branch out and become tile setters.... Baffled just baffled.
  • PRO
    The Kitchen Abode Ltd.

    Mr. Memes


    Your response is exactly what I expected, just another derogatory generality. You have no knowledge whatsoever as to my background, experience or skill set. If you were to engage in a more conducive discussion you might be surprised at my depth of experience and knowledge concerning tile setting. I'm always open to the experiences of others and to evaluate the merits of their ideas.

  • Mr. Memes
    Wait a minute....is this Houzz site a Canadian site?.... I may have been had all along here:( lol
  • PRO
    GreenDesigns

    What is your CTI#? I know that there are several forum participants that have that accolade. I suspect Corrector knows several as well, that could chime in, since he is always on the money when attempting to set straight hack work practices. That is the whole purpose of the designation, and the handbook. It sets apart those who can do it correctly, and those who cannot.

    Bettering the industry by eliminating the hacks who do not follow industry standards is a very worthy goal. People do have the opportunity to learn and better their practices and their businesses, if they just make the effort. There's plenty of opportunity everywhere.

    Every single Schluter rep for instance used to set tile. They have no problem working along side you on a project to learn their system if you can't attend one of their many hands on classes. Schluter isn't the only company willing to help better skills. They can't create someone who wants to learn though.

    It's the ones who rest on imaginary accolades and who refuse to learn or adapt that won't make it.

  • ci_lantro

    In this instance we will be glueing ceramic tiles over an area where we removed parket flooring which was laid over the original tile floor. When we removed the parket there was a layer of contact cement that stuck to the old tile.


    I suspect that what you are calling contact cement is what we would call mastic on this side of the pond.


    Contact cement here is something that is brushed or rolled on with a paint roller. Mastic is spread with a notched trowel.


    Got pictures of the stuff?

  • Mr. Memes
    Buhahahaha..... Ahh they really need to make a laughing emoji on this site......that's funny.
    Certification is not required for installing tile.
    If you're asking if I had 2 year apprenticeship is correct. I had 3 yrs. I don't only do tile. I'm also a carpenter I'm also a plumber I'm Also a certified HVAC & masonry specialist.
    Like I said go by the book I'm not picking on anyone who hasn't started with me 1st. The tiling trade online forum(s) is by far the most misleading trade help you can find.
    Greendesigns......make sure you switch your account to corrector before replying and shaming me some more.
  • PRO
    The Kitchen Abode Ltd.

    "The tiling trade online forum(s) is by far the most misleading trade help you can find."


    At last something we have common agreement on.


    False - "As long as one uses a waterproofing it does not matter the material used for the tile backer board"

    False - "Just overwater a cement for use as a Self-Leveler".

    False - "Building Codes do not define permissible tile backer boards".

    False - "If one uses Schluter they still need to use a mud shower pan".

    False - "Voiding warranties does not matter"


    You are absolutely right, there is a considerable amount of misleading information being spread around.

  • geoffrey_b

    I don't believe anybody brought up the fact that to ensure a good job - they should really rip out the tile - down to the cement floor. I have never been a fan of the 'go over the old' type of job.

  • Dafna Kremer

    Oh my goodness this question certainly stirred up a storm . Well to set the record straight we do not live in the USA and things are done differently here but they actually work. Yes tiles are laid over old tiles and yes they use adhesive/ glue.


    Anyhow we took your advice Mr Memes and Kat_ky and we ground off the old contact cement residule. We used a very rough disc so that it would score the old tiles as insurance against the risk of having missed some old glue here and there. A messy exhausting job but worth it if it will prevent a bad bond.


    A proffessional is laying the new tiles as I write this.

    Thanks for your help.

  • geoffrey_b

    Well to set the record straight we do not live in the USA and things are done differently here but they actually work. Yes tiles are laid over old tiles and yes they use adhesive/ glue.


    Excuse me - but whatever country you live in - doesn't make an inferior job better. Most of the tiles I've installed in our homes were made in Italy. The instructions clearly say to use thinset - not liquid nails or mastic. If you want the job to last and guarantee your result you need to use the correct products. With your logic - the next owners can put another layer on top of yours, etc.

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