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Thread: Bathroom Fitting - Problem w/New Tiled Floor (Help)

  1. #1
    Master ~dadam02~'s Avatar
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    Bathroom Fitting - Problem w/New Tiled Floor (Help)

    Howdy folks, I'm in need of some advice. I'm currently in the process of doing a total house renovation and as part of this I've had one of our bathrooms completely gutted and refitted. I enlisted the help of a local plumber, and paid a fair wedge for the privilege. This was in September, fast forward to March and the tiled floor is slowly breaking up, grout is beginning to crack, the floor creaks in certain places and feels unsteady to walk on and most certainly no longer solid underfoot.

    I've told my plumber this and he is visiting on Saturday to take a look so i want to be armed with as much info as possible in advance of this so that i don't get palmed off with some wishy washy rubbish and ensure i can try to push him in the direction i need to in order to get a resolution.

    So this is the floor before the sub floor way put down and tiles laid. The joist 2nd from left looks a little suspect with a crack running almost the entire length.



    This is the floor before the toilet was plumbed in:



    This is the floor after the toilet plumbing had been complete, i notice the sub floor seems to be in many different pieces now, supposedly this will compromise the strength of it?



    This is behind the bath panel, i notice the tiler has used a layer of tile adhesive thicker than the tiles. Is this expected? You can probably make out a craxck through the thickness of it, and a crack developing between the adhesive and the floor, presumably the whole lot is coming away.



    Sorry for the lack of great pictures, these seem to be the only ones i can find on my phone.

    Anyone care to enlighten me as to where the issues may be with regard to how my floor has been laid, and where any shortcuts look to have been taken? Also, what should have happened to ensure the floor was solid before the tiles were laid. And lastly, and i imagine most painfully, what do i need to do to fix it and is it likely to be a pricey one (assuming my plumber tries to wriggle out of it).

    Thanks in advance.

  2. #2
    Grand Master
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    Tiles over board on joists are always going to move IMO.

    mike

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    Craftsman eletos's Avatar
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    What sub-floor was installed, 18mm marine ply? Difficult to make out from the pics. Did the tiler use a good quality flexible adhesive for the tiles? Any underfloor heating?


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  4. #4
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    I wouldn't be as concerned about the crack in the joist as much as I would be about the cuts for the waste pipe! It looks (hard to be sure) that on a few of the joists the waste pipe has been let in by chopping out well over half the joist depth.
    That's a big no no!

    And it also looks like particle board or similar rather than ply which has been used, so bound to crack as others have mentioned.

  5. #5
    Yes suspended floor will always have this problem made worse by the small bits of wood. In my opinion 9mm ply or equivalent should have been put down and screwed every few inches to the joists, but of course this raises the bathroom floor.

    The good news is that it is only a little work to cut the grout out and re-grout - grout is "sacrificial" and cracks rather than the tiles.

  6. #6
    Grand Master Chris_in_the_UK's Avatar
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    If the sub floor is not decent thickness ply (min 18mm) then it will flex.
    When you look long into an abyss, the abyss looks long into you.........

  7. #7
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    When fitting tiles on joists, the plumber should use a tanking kit, or matting. On matting, the tiles will not move as they're stuck to the matt, not the joists. I'd prefer (and had installed) a full tanking kit, so no moisture can ever escape through the floor to the wooden joists.

    http://www.toppstiles.co.uk/tprod877...tting-1m2.html

    https://www.wetrooms-online.com/wet-...g-tanking.html

  8. #8
    Craftsman eletos's Avatar
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    Having a second look I would be more concerned about the notched joists with what looks to be 40mm pipe running through as well, PLUS close proximity to another run of 40mm pipework drilled through the joists.

    Don't fill your bath too full.


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  9. #9
    Quote Originally Posted by MB2 View Post
    Yes suspended floor will always have this problem made worse by the small bits of wood. In my opinion 9mm ply or equivalent should have been put down and screwed every few inches to the joists, but of course this raises the bathroom floor.

    The good news is that it is only a little work to cut the grout out and re-grout - grout is "sacrificial" and cracks rather than the tiles.
    This


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  10. #10
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    The fact the floor creaks explains the break up of grout. Subfloor is poor and as already said should have been better fitted and screwed at 150 centres. A layer of ditra mat would have helped lessen the chance of movement too

  11. #11
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    What Demonloop said. My brother is a tiler and says matting should be used here...

    And yep, the various big fat holes in the joists ain't great!

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    Master ~dadam02~'s Avatar
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    Thanks all for the feedback, super helpful. So from your feedback it's clear that having cracking in the grout after 6 months means theres way too much flex in the current floor and therefore any rectifying of the grout is merely masking a much more significant underlying issue which will simply materialise again if not treated properly. So to rectify this means taking the bathroom back up, potentially strengthening the joists and laying a much more solid subfloor including matting. I've a baby due in a week, this all sounds highly disruptive

    Has anyone any experience of cement board? Should a layer of cement board also be laid down on top of the subfloor?

  13. #13
    Master ~dadam02~'s Avatar
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    Quote Originally Posted by eletos View Post
    Did the tiler use a good quality flexible adhesive for the tiles? Any underfloor heating
    This was the adhesive that was used: http://products.kerakoll.com/gestion...012%20(EN).pdf

    No underfloor heating.

  14. #14
    Quote Originally Posted by ~dadam02~ View Post
    Thanks all for the feedback, super helpful. So from your feedback it's clear that having cracking in the grout after 6 months means theres way too much flex in the current floor and therefore any rectifying of the grout is merely masking a much more significant underlying issue which will simply materialise again if not treated properly. So to rectify this means taking the bathroom back up, potentially strengthening the joists and laying a much more solid subfloor including matting. I've a baby due in a week, this all sounds highly disruptive

    Has anyone any experience of cement board? Should a layer of cement board also be laid down on top of the subfloor?
    Yes we have used Cement board, for our upstairs bathroom, done about a year ago and have not suffered from any cracking. I would also say that our subfloor is also very good, no notched joists and noggins in place too. We also used flooring T&G chipboard on top of the joists and the cement board at 90 degree rotation.

  15. #15
    Quote Originally Posted by ~dadam02~ View Post
    Thanks all for the feedback, super helpful. So from your feedback it's clear that having cracking in the grout after 6 months means theres way too much flex in the current floor and therefore any rectifying of the grout is merely masking a much more significant underlying issue which will simply materialise again if not treated properly.
    I would say yes - and this is from experience - I DIY'd my own en-suite and despite what I thought were adequate precautions the grout needs re-doing every couple of years - it is only really one or two joints so quite quick to repair and I expect I have a joint just on the wrong side of a joist.

  16. #16
    Master ~dadam02~'s Avatar
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    So plumber has been, reckons its probably the adhesive (guess which part of the bathroom i purchased!) and doubts it could be the subfloor, as "its marine grade ply" and "i've never had a problem before". Obviously. I asked him if putting down cement board would improve the stability of the floor, to which he said doubt it as it's no stronger than the ply underneath. So i think a battle may ensue, but i'm up for it.

    This was the adhesive i purchased, on advice from the tile shop:

    http://www.bellissimotilesandtools.c...5kg-1446-p.asp

    http://products.kerakoll.com/gestion...%20UK_(EN).pdf

    Anyways, tiles are going to come up and we'll look at the sub floor when its exposed. I'll get some proper pics once its exposed and post on here.

    Interestingly, whilst pulling up the carpet near the door to the bathroom i noticed this crack in the adhesive at the point where 2 panels of the sub floor boards meet, which suggests to me there is some weakness at that point at the very least and may possibly points to weakness in the subfloor. I have a carpenter/builder over today so i'll separately ask him his opinion on the joist situation.



    I'm not too fussed about taking the floor tiles up as i instantly regretted laying them when they were put down so this is at the very least a chance to replace the floor. Every cloud.
    Last edited by ~dadam02~; 25th March 2017 at 12:54.

  17. #17
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    When we had ours tiled last year on a suspended timber floor we had 21mm chipboard (caberfloor) screwed and glued, with hardiebacker cement board over the top, then Ditra matting on top of that. We have natural stone tiles over the top and no cracks yet. The tiler thought it was overkill, just the matting would do but for the extra few hundred £ on cement board I thought it was best to take no chances. Our kitchen diner had large format porcelain tiles with the same system underneath also hasn't cracked yet.

  18. #18
    Master ~dadam02~'s Avatar
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    This is my thought, i don't/didn't mind paying the extra couple of hundred for a proper job, in fact i expect to pay it if the job warrants it. Sounds like you nailed it though, how much height did it ultimately add to the floor?

  19. #19
    Master IAmATeaf's Avatar
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    It does look like the ply floor has moved, the fact that you said it creaks in some places confirms this. Do you know what length screws were used to screw the ply to the joists?

    I have a similar problem, in my case only 1.5" screws were used so the ply has moved resulting in the not only the grout cracking but a few tiles are loose. For me the builder wasn't interested so at some stage I'll have to pull it all up and then properly redo it.

  20. #20
    Grand Master thieuster's Avatar
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    Not helping I know... Why did you use plywood (as seen on British house renovations as well...) and not Lewis dovetail decking? A British product widely used in nearly all older homes in NL. I have this decking in my bathroom for 13 yrs now - no problems

  21. #21
    Grand Master thieuster's Avatar
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    Quote Originally Posted by thieuster View Post
    Not helping I know... Why did you use plywood (as seen on British house renovations as well...) and not Lewis dovetail decking? A British product widely used in nearly all older homes in NL. I have this decking in my bathroom for 13 yrs now - no problems
    http://reppel.nl/static/img/content/...-doorsnede.gif

  22. #22
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    there will always be a settle period for tiles on joists and ply, the added weight will do this of course, the easiest way to rectify this would be to remove the grout, and then use an additive to flexible grout, you can get it from Topps Tiles, it is basically a thick PVA glue that you mix in with the grout, this makes it much more flexible and forgiving to floor movement, I used it in mine.

    I used 25 mm WBP plywood (Water and boil proof) on the floors to give it more rigidity, and then tiled straight onto that. http://www.builderdepot.co.uk/25mm-x...l-plywood.html

    here is a link to my post about it - http://forum.tz-uk.com/showthread.ph...=1#post3591577

    good luck with it all matey.

  23. #23
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    We recently did our whole house in porcelain and engineered timber floor. Really wished i had looked into vinyl flooring, you avoid any of these issues and its warmer underfoot and alot tougher than engineered floor. Something to consider perhaps..

  24. #24
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    I never plywood a floor before tiling on it any more.
    The problem seems to be the sub floor and that it isn't fixed properly.
    If the subfloor is not right then no adhesive or grout will be good enough to stop movement and eventually cracking.

    I use a hardibacker board which is a cement board where there is no electric underfloor heating.
    I make sure the floor underneath is fixed solid to the joists and then prime that floor before laying the board on a thin layer of flexible floor tile adhesive.
    I then screw the boards where the pre formed marks are.
    I scrim the joints and apply adhesive over the joints.
    I then prime the boards again and tile.
    Flexible adhesive and grout are used.

  25. #25
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    Is it just me or is the plywood down directly on top of the joists?

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  26. #26
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    Quote Originally Posted by ~dadam02~ View Post

    This is behind the bath panel, i notice the tiler has used a layer of tile adhesive thicker than the tiles. Is this expected? You can probably make out a craxck through the thickness of it, and a crack developing between the adhesive and the floor, presumably the whole lot is coming away.

    Tile adhesive should not be used as a screed and that appears to be what your tiler has done. It is simply an adhesive, to fix the tiles to the floor, and doesn't have any inherent strength. Using it on a large scale in this manner is risky on a rock solid floor and definitely a recipe for trouble where the floor may have some movement. Judging by the thickness used in at least two separate areas you may have scope to use a thicker ply base with just the correct amount of adhesive, to give you a more solid floor.

  27. #27
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    Quote Originally Posted by ~dadam02~ View Post
    This is my thought, i don't/didn't mind paying the extra couple of hundred for a proper job, in fact i expect to pay it if the job warrants it. Sounds like you nailed it though, how much height did it ultimately add to the floor?
    The 21mm caberfloor base is on the joist so that's the subfloor, the cement board is 6mm and its on a bed of adhesive so another couple of mm. The matting is around 5mm, I believe that is also glued down so an extra couple of mm there. Around 15mm on top of the 21mm subfloor. It is a bit higher (maybe 10mm) than the floor in the hallway but honestly it doesn't notice.

  28. #28
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    My bathroom no where near as big but I used a unibond wooden floor tile adhesive and grouted with grout for use on wooden floors- now it's been 10 years and they went straight on top of the floor boards (made sure they were very solidly down) and I've had no cracking or movement- sorry but I'd be really worried about those joists and if the floors back up strengthen those by bolting some extra timber to sandwich the cut away one- from the picture it looks like he has cut at least 1/2 way through most of the joists
    Last edited by lewie; 26th March 2017 at 08:19.

  29. #29
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    Quote Originally Posted by lewie View Post
    I'd be really worried about those joists and if the floors back up strengthen those by bolting some extra timber to sandwich the cut away one- from the picture it looks like he has cut at least 1/2 way through most of the joists
    I think the picture might be deceiving, if you look at the first 2 on the left you can see the joist is drilled for the pipe and the cut above it is a notch.

  30. #30
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    Phew ah yes good spot

  31. #31
    The floor will flex, so the tiler should have used an appropriate flexible adhesive and grout, and the appropriate ply, screwed to 200mm spacing.

    Modern professional adhesives are highly flexible, and can allow you go down as low as 6mm ply ( or none with top of the range mapei)

    A combination of flex in the sub floor, under specced ply, poorly laid, poor choice of flexible adhesive could have caused this.

    Could simply be he's used a cheap adhesive



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