Tiles Cracking on Bathroom Floor - Help Needed!!

Discussion in 'Tilers' Talk' started by closetothebrink, Feb 29, 2008.

  1. closetothebrink

    closetothebrink New Member

    I had a new bathroom built in an upstairs extension last year. The ceramic floor tiles were laid directly onto the chipboard T&G boards. Everything was fine for 6 months, but a few weeks ago cracks started to appear in the tiles. All the cracks correspond with the joints in the chipboard flooring.

    My tiler claims the flexible adhesive he used is fine for use on those boards, so the problem must be excessive movement of the boards. However, the newly plastered ceilings downstairs are still perfect, so the joists cannot be moving excessively. One theory he has is that water from a minor bath leak (during installation) has managed to get into all the board joints - somehow causing them to move.

    Any advice and views on what could have caused the problem would be welcomed. Also, what can I do to fix the problem? At some stage, I will have to retile the floor, but don't want to do this & get the same problem occurring again.

    Many thanks in advance.
     
  2. handcraft

    handcraft New Member

    i think your tiler might be pulling your leg a decent carpenter would have used waterproof glue in all his board joints

    lee
     
  3. ejj

    ejj Member

    It is normal practise to overboard the chipboard with 12 mm WBP Plywood before laying the tiles.


    John
     
  4. GKU

    GKU New Member

    <u>ejj</u> has hit the nail right on the head there me old china - chipboard should have been boarded over with ply - laying straight on to chipboard is poor practice - it is'nt strong enough or durable enough !!!
     
  5. handcraft

    handcraft New Member

    22mm p5 t and g chipboard glued and screwed to joist should be more than sufficient

    lee
     
  6. GKU

    GKU New Member

    I'm syill with ejj on this
     
  7. GKU

    GKU New Member

    Sorry - --- <u>still</u> with ejj on this
     
  8. handcraft

    handcraft New Member

    im a carpenter and when i do 1st fix that is all i do and they tile directly onto it ?

    lee
     
  9. jasonb

    jasonb New Member

    I'd overboard as well.

    Handcraft, Norbord who make Caberfloor say you should only tile onto their chipboard if you place nogging at 300cts, Do you do that? I've yet to see a house thit that spec structural floor.

    If not then they suggest overboarding with 15mm ply, have a look a the floor preparation part of their tech guide.

    Jason
     
  10. handcraft

    handcraft New Member

    i do 4 centres im a chippy not a tiler all i was saying is that when i do 1st fix this is what i do and the tiler never has problems

    lee
     
  11. GKU

    GKU New Member

    <u>STILL</u> with ejj & jasonb on this , - we are not calling into doubt what <u>you</u> do handcraft , its what the tilers are doing afterwards (or not doing , more to the point)- it only takes a few water spillages for some water to get down through somewhere (especially in a bathroom) and chipboard goes like a sponge , even the waterproof stuff only resists a certain amount of water , it then disfigures and weakens - had to completely re-board a floor recently due to water leakage on it , it had dips & bumps everywhere - boarded it with woodchip , then put ply on top , then tiled it .
     
  12. GKU

    GKU New Member

    Oh , and I can tell you this <u>handcraft</u> - not all chippy's are as thorough as you - I have been to many bathrooms where the chipboard has'nt been glued at the joints - all trades have good and bad working in them , its a fact of life i'm afraid , you only have to read these forums to have that made clear to you sometimes , eh buddy ? - still its makes more work for us does'nt it ?
     
  13. GKU

    GKU New Member

    <u>jasonb</u> - just a point on the NOBORD tech guide which has'nt been pointed out - they state that their boarding is moisture RESISTANT <u>not</u> moisture PROOF , there is a difference !!! , water can still get in or through eventually .
     
  14. jasonb

    jasonb New Member

    Press, I'm fully aware that V313 moisture resistant chipboard will only resist wetting to a certain extent, I use a lot of MR MDF and if you get that wet enough it will swell by at least 50%. Its only the glue that is resistant, the wood fibres will still swell etc

    Just doing a bathroom at the moment where water got through the shower tiling around the dado tiles, even the studwork has rotted not to mention the flooring.

    Its also what I tell people who think that using Aquapanel, waterproof adhesive, waterproof grout, etc will make their shower watertight, all these products will not deteriorate when they come into contact with water but they DO NOT provide a total barrier to the passage of water.

    Jason
     
  15. GKU

    GKU New Member

    <u>jasonb</u> - could'nt have put it better myself, I was'nt having a poke at you , I was just pointing it out to other people that MOISTURE RESISTANT and MOISTURE PROOF are different !!! many people do not realise this point (they think that they mean the same thing and its not) and as you say , they think it will all be ok because they have used this type of stuff
     
  16. handcraft

    handcraft New Member

    cheers for defending me press16 as i said im not a tiler i was just stating what i do

    when i lay a floor i glue and screw and waterproof tape the joints when im done laying aswell thought it was common practice

    lee
     
  17. Captain Leaky

    Captain Leaky New Member

    Never tile straight onto chipboard. Ply is the only suitable timber surface. Always overboard.
     
  18. chip off the block

    chip off the block New Member

    just read norbord spec you linked too and it says about overlaying with 4mm ply for tiling! Yes i know it is supost to be minimum 15mm blah blah blah
     
  19. jasonb

    jasonb New Member

    Read it again, the 4mm is suggested for resiliant materials such as vinyl tile & sheet to stop joints/fixings ghosting through. On the next column to the right they say 15mm for tiling

    Jason
     
  20. chip off the block

    chip off the block New Member

    i thought it was a bit odd. must of read the wrong coloum some how annd i only scanned it didnt really read fully so fair enough
     

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