Grout Cracking on Tiled Floor
Discussion
We have recently (last week) had a new bathroom fitted with floor tiles to match those on the walls, however the grout on these tiles has cracked and become loose.
The fitter removed the original grout and re grouted thinking it may be a bad batch or similar, however it has happened again.
The floor tiles have been layed on a flexible adhesive on a 5mm layer of hardboard on top of the floorboards and we have come to the conclusion that the floor is obviously flexing and causing the grout to crack.
Question is - what is the best solution to stop any flex and ensure the tiles stay solid?
I've read that circa 1/2 inch ply with cement backer board on top is best but looking for some opinions!
Thanks
The fitter removed the original grout and re grouted thinking it may be a bad batch or similar, however it has happened again.
The floor tiles have been layed on a flexible adhesive on a 5mm layer of hardboard on top of the floorboards and we have come to the conclusion that the floor is obviously flexing and causing the grout to crack.
Question is - what is the best solution to stop any flex and ensure the tiles stay solid?
I've read that circa 1/2 inch ply with cement backer board on top is best but looking for some opinions!
Thanks
I used a flexible adhesive when I fitted tiles to my upstairs bathroom some years back. Whilst the tiles remained firm, the grout cracked and eventually came away. I was once told this was due to using a flexible adhesive rather than a normal one. Had I used a normal one the grout would not have cracked and comeout. How true this is I do not know so I would be interested to hear anyone else's comments regarding the OP's question.
I've since left the tiles without grout but now hate the decor of the room so want to change it and the tiles, and preferably not make the same mistake again.
I've since left the tiles without grout but now hate the decor of the room so want to change it and the tiles, and preferably not make the same mistake again.
Hi
Your fitter shouldn't have tiled on top of hard board, a big no no!
The grouts cracking because the tiles are moving due to what's underneath them.
No matter how many times he re-grouts it it'll keep happening.
The fitter should've ensured the floor boards were secure then either over boarded with, ideally, something like Hardibacker board or if using timber then ply (adhesive manufacturers normally insist on a minimum of 18 mm for them to warrant it).
For what it's worth I'm a tiler by trade.
Your fitter shouldn't have tiled on top of hard board, a big no no!
The grouts cracking because the tiles are moving due to what's underneath them.
No matter how many times he re-grouts it it'll keep happening.
The fitter should've ensured the floor boards were secure then either over boarded with, ideally, something like Hardibacker board or if using timber then ply (adhesive manufacturers normally insist on a minimum of 18 mm for them to warrant it).
For what it's worth I'm a tiler by trade.
The floor is flexing hence the grout cracking. Minimum for ceramic tiles on floorboards is 1/2 wbp ply srewed down onto the joists or the boards ripped up and 3/4 wbp ply screwed directly onto the joists again.
Using hardboard is cowboying it so the lot needs to be pulled up and done correctly.
Using hardboard is cowboying it so the lot needs to be pulled up and done correctly.
GhiaX said:
I used a flexible adhesive when I fitted tiles to my upstairs bathroom some years back. Whilst the tiles remained firm, the grout cracked and eventually came away. I was once told this was due to using a flexible adhesive rather than a normal one. Had I used a normal one the grout would not have cracked and comeout. How true this is I do not know so I would be interested to hear anyone else's comments regarding the OP's question.
I've since left the tiles without grout but now hate the decor of the room so want to change it and the tiles, and preferably not make the same mistake again.
Utter bI've since left the tiles without grout but now hate the decor of the room so want to change it and the tiles, and preferably not make the same mistake again.
ks. The grout cracked because there was too much movement in the floor. OP - Was the person who laid the tiles actually a tiler? I find it hard to believe that they were. Tiling over 5mm hardboard is ridiculous. As murphy and wolf have said you cannot fix, it is a rip up and do properly job I am afraid.
Was there anything in the contract about the tiling method and preparation? If that isn't what they have done and they refuse to fix you may have to sue for breach.
Thanks for the responses all, the fitter was a family friend who is a plumber by trade so no formal contract agreed - i fully understood what i was getting into by doing this but some of the frankly outrageous quotes we had forced our hand.
I know it needs ripping up and starting again so happy to do so (area is circa 2sqm), just wanted to see what the consensus was on the floor preparation.
It seems the best option is to remove the tiles and thin hardboard, leaving the floorboards down and over boarding with either ply or concrete hardiebacker.
Ideally the solution would be as thin as possible so the floor in the bathroom isnt significantly higher than that in the hall - so shall i go for the 6mm or 12mm hardiebacker or 1/4 or 1/2 inch ply?
I know it needs ripping up and starting again so happy to do so (area is circa 2sqm), just wanted to see what the consensus was on the floor preparation.
It seems the best option is to remove the tiles and thin hardboard, leaving the floorboards down and over boarding with either ply or concrete hardiebacker.
Ideally the solution would be as thin as possible so the floor in the bathroom isnt significantly higher than that in the hall - so shall i go for the 6mm or 12mm hardiebacker or 1/4 or 1/2 inch ply?
944fan said:
GhiaX said:
I used a flexible adhesive when I fitted tiles to my upstairs bathroom some years back. Whilst the tiles remained firm, the grout cracked and eventually came away. I was once told this was due to using a flexible adhesive rather than a normal one. Had I used a normal one the grout would not have cracked and comeout. How true this is I do not know so I would be interested to hear anyone else's comments regarding the OP's question.
I've since left the tiles without grout but now hate the decor of the room so want to change it and the tiles, and preferably not make the same mistake again.
Utter bI've since left the tiles without grout but now hate the decor of the room so want to change it and the tiles, and preferably not make the same mistake again.
ks. The grout cracked because there was too much movement in the floor. OP - Was the person who laid the tiles actually a tiler? I find it hard to believe that they were. Tiling over 5mm hardboard is ridiculous. As murphy and wolf have said you cannot fix, it is a rip up and do properly job I am afraid.
Was there anything in the contract about the tiling method and preparation? If that isn't what they have done and they refuse to fix you may have to sue for breach.
TDan said:
Thanks for the responses all, the fitter was a family friend who is a plumber by trade so no formal contract agreed - i fully understood what i was getting into by doing this but some of the frankly outrageous quotes we had forced our hand.
I know it needs ripping up and starting again so happy to do so (area is circa 2sqm), just wanted to see what the consensus was on the floor preparation.
It seems the best option is to remove the tiles and thin hardboard, leaving the floorboards down and over boarding with either ply or concrete hardiebacker.
Ideally the solution would be as thin as possible so the floor in the bathroom isnt significantly higher than that in the hall - so shall i go for the 6mm or 12mm hardiebacker or 1/4 or 1/2 inch ply?
6mm Hardibacker will be fine. This must be set down with tile adhesive as well as being screwed. This will give you the least height difference, unless you want to rip up the floor boards and replace with 25mm ply. If using ply, WBP is fine, no need for the extra cost of marine grade. You do need to seal the undersides and edges but not the face to be tiled. I know it needs ripping up and starting again so happy to do so (area is circa 2sqm), just wanted to see what the consensus was on the floor preparation.
It seems the best option is to remove the tiles and thin hardboard, leaving the floorboards down and over boarding with either ply or concrete hardiebacker.
Ideally the solution would be as thin as possible so the floor in the bathroom isnt significantly higher than that in the hall - so shall i go for the 6mm or 12mm hardiebacker or 1/4 or 1/2 inch ply?
If the floor is really troublesome then you could use a decoupling membrane such as Ditra but you still need to remove the bounce from the floor. Do you know what the pitch/size/span of the joists is? You could try a fat boy test after the tiles are up. Fill a glass of water right to the brim, put it in the centre of the floor and get your fatest mate to walk around. If there is any water spilt there is to much bounce.
If it has been laid that badly, and it has, you may be able to get the tiles up without damaging them and re-use. If you are going to re do this yourself and there is no reason why you shouldn't my top tip is to make sure you buy decent trade addy and grout and not the s
t they sell in the DIY sheds. BAL is highly recommended but there are others.The floor prep is not ideal, in place of 6mm ply really should have been something like, 'No More Ply', Hardibacker, or an uncoupling membrane like Ditra mat or Norcross Permalayer.
Assuming that the ply was primed first, and that tiles themselves aren't lifting, could be that standard grout is being used, rather than a flexible one.
What ever the preparation method, flexible adhesive and grout should be used when tiling onto timber floors.
Assuming that the ply was primed first, and that tiles themselves aren't lifting, could be that standard grout is being used, rather than a flexible one.
What ever the preparation method, flexible adhesive and grout should be used when tiling onto timber floors.
I think i'll be going down the route of ripping up the tiles and hardboard and replacing with the 6mm hardiebacker, secured with adhesive and screws to the floorboards (which i'll make sure are screwed down solid!) - fingers crossed, any more tips?
The adhesive was flexible trade stuff, not pre mixed and the same with the grout, i.e. suitable for floor use.
Re quotes, we had - £4,300 / £4,500 / £5,500 - this is for a 1.8m x 2.2m room fully tiled with shower over bath, moving of toilet and vanity position and new towel rail.
At the moment we're at £2,783 including all labour, materials and even the towels and fittings so a considerable saving - although hard to put a price on the additional hassle of the floor!
The adhesive was flexible trade stuff, not pre mixed and the same with the grout, i.e. suitable for floor use.
Re quotes, we had - £4,300 / £4,500 / £5,500 - this is for a 1.8m x 2.2m room fully tiled with shower over bath, moving of toilet and vanity position and new towel rail.
At the moment we're at £2,783 including all labour, materials and even the towels and fittings so a considerable saving - although hard to put a price on the additional hassle of the floor!
That should work fine.
It should only take a tiler a day to board and tile that though so not a huge cost in labour if you're not confident doing it yourself.
If you do tackle it though use an independent tile shop where the staff can advise on what materials to use and how to use them. Avoid places like Topps if you need good advice!
Good luck with it.
It should only take a tiler a day to board and tile that though so not a huge cost in labour if you're not confident doing it yourself.
If you do tackle it though use an independent tile shop where the staff can advise on what materials to use and how to use them. Avoid places like Topps if you need good advice!
Good luck with it.
I'm interested to know what is 'good grout' since BAL seems to be recommended often enough and is what I've used in various jobs. However, I have some grout cracking in my upstairs bathroom which I replaced the floorboards with 18mm WDP and added extra noggings and screws at less than 150mm centres. I didn't use ditra matting since I wasn't aware of it at the time (4-5 years ago).
Hoping to get away with hawking out the grout and redoing as it's a limited area and might not be helped by the radiator pipes running underneath this section. If need be I can replace the two tiles this has occured on (60cm x 40cm travertine) but would prefer to try re grouting first. I'm sure the BAL grout was flexible (the adhesive certainly was).
Hoping to get away with hawking out the grout and redoing as it's a limited area and might not be helped by the radiator pipes running underneath this section. If need be I can replace the two tiles this has occured on (60cm x 40cm travertine) but would prefer to try re grouting first. I'm sure the BAL grout was flexible (the adhesive certainly was).
BAL is a quality trade adhesive used by many professionals. Perhaps tonker has confused it with something else?
Ditra matting has specific applications and is useful in problems floors but many suspend timber floors can be successfully tiled without it and no cracking. Using ditra alone will not prevent cracking if the floor is not properly prepared to prevent movement.
Ditra matting has specific applications and is useful in problems floors but many suspend timber floors can be successfully tiled without it and no cracking. Using ditra alone will not prevent cracking if the floor is not properly prepared to prevent movement.
Shame it's 5 years too late to find that out since I don't fancy pulling it all up now. 
I'll just see if I can regrout with flexible or mix in latex as you suggest. I seem to remember reading up when I did the job and 18mm WBP was recommended (with lots of screws to hold it down), so I guess things change over the years as new products come out. It was the first time I'd tiled upstairs since all my other tiling is downstairs on concrete flooring and hasn't been a problem, so just sod's law that this job has a problem.
I'll just see if I can regrout with flexible or mix in latex as you suggest. I seem to remember reading up when I did the job and 18mm WBP was recommended (with lots of screws to hold it down), so I guess things change over the years as new products come out. It was the first time I'd tiled upstairs since all my other tiling is downstairs on concrete flooring and hasn't been a problem, so just sod's law that this job has a problem. OldSkoolRS said:
Shame it's 5 years too late to find that out since I don't fancy pulling it all up now. I'll just see if I can regrout with flexible or mix in latex as you suggest. I seem to remember reading up when I did the job and 18mm WBP was recommended (with lots of screws to hold it down), so I guess things change over the years as new products come out. It was the first time I'd tiled upstairs since all my other tiling is downstairs on concrete flooring and hasn't been a problem, so just sod's law that this job has a problem.
18mm is ok for overboarding (15mm is the min for overboarding), but 25mm is required when replacing. If it has taken 5 years to crack then you probably don't have that much movement. Make sure to use a sanded flexible grout. Sanded grouts are required for the larger spacing on floors and are stronger, and thus less likely to crack. Although if you have limestone or marble tiles you shouldn't use sanded as it will sratch the tile I'll just see if I can regrout with flexible or mix in latex as you suggest. I seem to remember reading up when I did the job and 18mm WBP was recommended (with lots of screws to hold it down), so I guess things change over the years as new products come out. It was the first time I'd tiled upstairs since all my other tiling is downstairs on concrete flooring and hasn't been a problem, so just sod's law that this job has a problem. Gassing Station | Homes, Gardens and DIY | Top of Page | What's New | My Stuff