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Cracking and crumbling grout in a newly tiled floor

Discussion in 'Tiling' started by maggiemudge, 27 Mar 2010.

  1. maggiemudge

    maggiemudge

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    Help!! :(
    I have recently laid tiles on my suspended kitchen floor, the chipboard was replaced by the builder. I then laid Hardiebacker board and used a flexible adhesive. There is slight movement in one of the tiles-it makes a 'popping' sound when you walk on it... No tiles have cracked but the grout has crumbled/cracked, it started about 2 weeks after finishing the floor and is gradually getting worse. I really can't face taking the tiles up, is there the possiblity of replacing the grout with something more flexible which allows for slight movement?
     
  2. tictic

    tictic

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    never tile a suspended floor.
     
  3. Richard C

    Richard C

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    What did your builder replace the chipboard with? How thick was it? Please don’t say more chipboard!
    Do you know anything about the floor construction – size, depth & span of joists? What size is the kitchen? Exactly what flexible adhesive & grout was used? What thickness of Hardibacker? How was that fixed? Anything else you know about?

    It could be the wrong grout or adhesive was used or the adhesive was not laid correctly; tiles on a suspended floor must be laid on a continuous adhesive bed. What you describe has all the classic signs of movement likely due to excessive flexing or incorrect floor preparation. If the grout is going & tiles moving replacing the grout is not a solution. I’m afraid your going to have to resign your self to pulling the lot up & starting again but not before the floor is sorted out. Call the builder back & say you want it rectified.

    Sure you must have done tictic; think there is some confusion about what the OP is referring to here or are you being a little devious :LOL: ;)
     
  4. joe-90

    joe-90

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    My guess is that the backer board isn't fixed properly so nothing to do with the builder.
     
  5. Richard C

    Richard C

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    I now see I didn’t pay enough attention to the post last night & may have maligned builder unfairly :oops: all he appears to have done was lay a new floor.

    Await response from OP.
     
  6. tictic

    tictic

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    :rolleyes: :rolleyes: beer goggles on :oops: and flicking thro this forum and others :LOL:
    op...sorry for WRONG advice ;)
     
  7. maggiemudge

    maggiemudge

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    The kitchen is approximately 18ft x 10ft, sorry I don't know anything about floor constuction other than there's a gap underneath of about a metre. I used 6mm hardiebacker board and fixed them with hardiebacker screws at about 30cm intervals. The adhesive used was BAL single part (I think - I had to mix it with water), the grout was BAL wide joint, again I had to mix it with water. The only thing I can think I may have done is have the edge of the hardiebacker too close to the join of the chipboard but surely if I used enough screws it should have been secure. Would this explain why the grout began crumbling in one area and is now gradually spreading further along the kitchen?

    My builder has said I should have used a rubberised adhesive that doesn't set hard and allows for movement - does anyone know anything about this?

    Thank you for all your comments. :)
     
  8. maggiemudge

    maggiemudge

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    Whoops - also meant to say that the adhesive was spread all over the floor so tiles were laid on a continuous adhesive bed.
     
  9. tictic

    tictic

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  10. tictic

    tictic

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    b@@@dy computer keeps crashinnng ere.. :LOL:

    what size of tiles.
    what size of notched trowel.

    did you fix them yourself/have you done tile fixing before.
     
  11. maggiemudge

    maggiemudge

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    Yes, I did do it myself despite others saying to go with the easy option of vinyl!!! :evil: Should have listened to them...I have previously tiled a bathroom including the floor and also the walls of the kitchen and they all look good and the grout has stayed in perfectly but I suppose that wasn't a suspended floor.

    Right - here goes...
    *chipboard was moisture resistant and fixed with screws - builder did that
    *I didn't prime the chipboard
    *I don't think the builder put in extra support between the joists
    *possibly i may have mixed the adhesive incorrectly but I measured it out and the consistency looked the same as when I did bathroom floor last year
    *I only fixed a few tiles at a time, maximum of 3-4
    *I didn't intentionally leave a gap between hardiebacker boards but there may be a couple of mm
    *hardiebacker boards weren't staggered, no tape put on the joins but I did put adhesive over them
    *tiles were 33x33cm
    *trowel was as advised by people at Toppstiles as everything else was

    Probably a stupid question but if I have to take the tiles up and start again would I be able to reuse them and how would I get the adhesive off the backerboard to get a flat surface?

    Thanks for taking the time to respond
     
  12. tictic

    tictic

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    hi maggie ;)

    have to go back to what joe 90 said.
    problem is the installation of the backerboards...sorry..

    when you tap the tiles and hear a hollow sound,these ones will start to crack/lift..
    as for lifting and saving them and the backerboards,i dont think you will have much success there sorry.

    if you can lift any of the ones that sound hollow when tapping scrape addy from b/boards then relay any spare ones you have,it might work(for a while)..

    for re-grouting you will need to add bal...admix GT1 to your grout,will try post up a link for you.. ;)

    http://www.bal-adhesives.co.uk/products/admix-gt1
     
  13. Richard C

    Richard C

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    tictic has already covered where you went wrong with over boarding but the adhesive you used is fine providing the base is suitable. Your builder's suggestion of a latex based adhesive is OK but it’s a lot more expensive & if you get the tile base right, generally not necessary.

    As your going to have to do it again, personally I’d loose the chipboard; IMO it’s not really suitable as a floor material let alone as a tile base. Unless you live in a mansion, even a large bath/shower room is only going to be around half the size of your kitchen, with a correspondingly smaller joist span. A large ground floor kitchen is also subject to heavy use/traffic & is therefore going to need additional consideration to ensure it’s rigid enough as a tile base. I would considered a 25mm WBP ply & it probably wouldn’t need any over boarding if correctly laid but sometimes additional support is necessary with a large joist span, it depends on the individual floor; the gap underneath the floor makes no difference.

    I’m in 2 minds about over boarding; personally, I prefer to lay a new WBP ply floor if possible &, if doing that, I don’t really see the point of over boarding with backer board as well. Unless they are bonded together as well, one board over another is never going to be as rigid as a single board the same thickness & if the floor isn’t rigid enough, either beef up the joists &/or support or go thicker in the 1st place rather than overboard. 30 cm spacing for the screws is too wide, 20cm max.
     
  14. tictic

    tictic

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    overboarding...i think its one of those debates were, we all will have to agree to disagree.. ;)
    imo if its done properly it wont fail.

    one last thing maggie..you used spf,did you leave it the recommended time before grouting...16hrs.
    bit late to ask now,i know.. but always follow m.i. on "all materials" used on tile fixing and any other job..


    best of luck maggiemudge.
    tictic...
     
  15. maggiemudge

    maggiemudge

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    Thank you all for your advice :D

    I think I'll first have a go at replacing the couple of tiles that are making a popping sound and add the BAL admix to the grout and redo the grouting. If this doesn't work I'll resort to redoing the whole floor.

    Thanks again - I wish I had looked on here before starting...
     
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