hairline crack, slight flex in 2 tiles - to foam or not to foam? - Tile Advice

[digga_23]

In short:
would using some expanding foam behind 2 tiles that have a small amount of flex, where I presume adhesive has partially de-bonded help fill the void and re-glue the to tile to breeze block?

Or inject some kind of adhesive/silicone to where i can get to with grout removal?

The long:
Had tiling done in new bathroom 2.5 years ago.
Noticed a small hair line crack on sections of 2 tiles horizontals, scraped out partially and refilled - Now done this twice and see it's cracked again.

It appears there is a small amount of flex on two or three tiles inside the shower quadrant (row 4+5 from bottom, 61x30cm tiles), these back on to an outside wall (breeze block). If I push on the tiles hard I get about a 1mm flex and they move together and causes the grout to crack to open more and come out.
The other side is plasterboard and all seems solid.
If I knock on those tiles they do appear to be hollow, the bottom 3 rows do not sound hollow and I see no flex.

The shower quadrant door opens/closes, resulting in constant impact bangs on these sets of tiles, no doubt why the grout re-cracks after 4-5 months again.

Would removing the grout and shoving some expanding foam behind the tiles help bridge the gap and re-glue the adhesive?
Or try and get some silicone behind it?
I would really to avoid having to dismantle the shower quadrant and making a big mess of the bathroom (damaging tiles etc) and unlikely get a tiler to even turn up to rectify.

I have used foam before for this situation once before on a door tiled door reveal and there was a similar issue, i injected it with some foam, re-grouted and the issue never came back. Has any one done anything similar with success?

I was going to use fisher general purpose expanding foam, is there anything that may stick better?

thanks

 

[Jon_Hall]

I would remove the tiles and replace them. Also worth checking the other tiles on that wall to see if they are hollow sounding, if they are they should be removed and replaced to.
As the tiles are fixed to a block wall I wouldn't have thought that the shower door is opening and closing would be the cause of the failure, sounds like some settlement or movement to me.

 

[digga_23]

I would remove the tiles and replace them. Also worth checking the other tiles on that wall to see if they are hollow sounding, if they are they should be removed and replaced to.
As the tiles are fixed to a block wall I wouldn't have thought that the shower door is opening and closing would be the cause of the failure, sounds like some settlement or movement to me.

What I was afraid of.
I have ground the grout out and it appears there is about a 10-20mm gap behind the tiles and that the adhesive is certainly not going to the full edge of the tile, but also presuming perhaps it has also debonded anyway.

The tiles lower down that do not sound hollow appear to have adhesive going right to the edge of the tile.

If I manage to get these tiles off the wall,
what would you suggest priming the wall with and what adhesive is best to use ?

I have some "everbuild water resistant tile adhesive", the carpenter used for our other bathroom when he built a side bath panel in the summer. Is this stuff any good to use?

 

[Jon_Hall]

Once you have removed the cracked tiles, you should be able to see if the surrounding tiles have a good solid bed of adhesive beneath them, also check the back of the tiles you have removed to see how well they were fixed. If the surrounding tiles are ok then you will need to prime the block work 1:4 with SBR, then use a C2 adhesive to fix the tiles.
Also the gap underneath the tiles seems excessive at 10 - 20mm, is this because the tiles have blown from the wall and tented?

 

[digga_23]

Once you have removed the cracked tiles, you should be able to see if the surrounding tiles have a good solid bed of adhesive beneath them, also check the back of the tiles you have removed to see how well they were fixed. If the surrounding tiles are ok then you will need to prime the block work 1:4 with SBR, then use a C2 adhesive to fix the tiles.
Also the gap underneath the tiles seems excessive at 10 - 20mm, is this because the tiles have blown from the wall and tented?

I know the tiler said the wall was not level. It was the outside masonry wall, that was then an internal wall after we had a rear extension.
It doesn't seem to have blown away from the wall more than a mm, so it must have been laid like this.

Going to try my best to find a tiler, but like any other trade it's going to be unlikely or they wont want this kind of small job.
I am worried I wont be able to get the tile bed nice and flat, as i've never done one before and why i'd rather get a professional.

thanks for your help

 

[digga_23]

Would "Bal flex one" be a recommended product here ?
I just measured and there's up to a 16mm gap between back of tile and wall in some areas. This states it can be up to 15mm of build up, sticks to cement/masonary and is suitable for showers

 

[digga_23]

Or perhaps ProFlex SP: Rapid Set Flexible Tile Adhesive
which states it is good for vibrations. I was thinking i may be able to just go round the edges of the tile if it's stuck well enough in the middle.

 

[Jon_Hall]

If the tile is cracked it will need replacing, as you will get water ingress through the crack. You will need to remove all of the old adhesive then get as near as possible to a solid bed of adhesive beneath the tile. Check the adhesive can go to the required thickness, as some can only bed up to 10-12mm.

 

[digga_23]

There are no cracked tiles. The issue is a very tiny hairline crack is made in the grout between 2 tiles every 6-8 months (verticals) . I re-grout it and then it eventually re appears.

I removed all the grout around several tiles and noticed there is a 1mm flex when pushing hard on 2 adjacent tiles, there also doesn't appear to be adhesive 30-50mm from the edges.

The shower quadrant door bangs shut on these tiles when closed and i can just about see a tiny bit of movement, which no doubt causes the hairline to crack over a period of time, maybe even caused the adhesive to loosen from the tile in the first place.

The shower quadrant screws through the middle of this tile so it would be impossible for it to actually fall off, that and it's been there for 2.5 years.

I have made a video to hopefully show this better:

Streamable Video - https://streamable.com/7s0ywt <<--

This is a picture of the tiles (I have ground out the grout to accentuate the flexing

20210115-100743 - https://ibb.co/xGtC2nn <<--

I cannot seem to find a tiler that is even willing to have a look, no doubt they are scared it's some kind of water damage based nightmare, which it definitely isn't.
This is why I was just thinking of injecting something like silicone around the 2 tiles via the grout lines to hopefully re-stick it, or even trying to shove some grout behind it to stop it being able to flex

 

[Jon_Hall]

Tiles should not be moving like that on a solid wall, it may be just the grout that is holding them in place. The tiles possibly haven't got sufficient adhesive beneath them. I would rake out the grout around the offending tiles and see if you can carefully remove them. Once you have removed them you can see what you are dealing with. If you can, send another video of the adhesive bed and the edge of the surrounding tiles.

 

[digga_23]

Tiles should not be moving like that on a solid wall, it may be just the grout that is holding them in place. The tiles possibly haven't got sufficient adhesive beneath them. I would rake out the grout around the offending tiles and see if you can carefully remove them. Once you have removed them you can see what you are dealing with. If you can, send another video of the adhesive bed and the edge of the surrounding tiles.

Hi Jon,


I was wondering if I could just inject something through the grout holes (silicone, foam) as there is definitely not adhesive going all the way to the edges to help it stick further.

Originally I was just going to silicone the grout line as i know that will allow that 0.5mm of flex and forget about it, but i'd rather try and stick the tile down a bit more now i know it's not got enough adhesive and wondered if any one had any other ideas than trying to get them off.

I understand removing any suspect tiles from a wall is probably the "best" thing to do, but I cannot find any professional who wants to do it, there's only 2 that are moving and they are 4-5ft high off the ground. The bottom are all fine, presumably having more adhesive.

Unfortunately as you can see from the picture, to get those 2 tiles out would mean removing all the silicone around the whole shower tray-> quadrant, unscrewing the quadrant fixings, silicone etc and lifting out and i bet it's bloody heavy.
Removing the quadrant upstand silicone, fixings etc. disturbing the tray to tile silicone. If that all does get remove without damage to threads, rawl plugs/screws etc only then could i give it a go at chasing the rest of the grout out in the hope i can remove that tile without smashing it or damaging others. If i do get the thing off I have to re-apply adhesive between a level of 10->16mm ton an uneven wall without it looking horrendous, scraping all the cut silicone off (shower quadrant will be very difficult) and putting all the other silicone waterproofing back in the hope that is again water tight and that I have used sufficient adhesive and primed the wall that it doesn't happen again.
If i start cracking tiles i am in for even more issues. I'm all for doing things properly but I don't want to demolish the whole bathroom or make things worse.

 

[Jon_Hall]

I've just thought of another option that may work, but I cant guarantee it and it will probably be messy. We sell a 3 part epoxy grout, you could mix up the base liquid and the accelerator, add a little of the sand to bulk it out a bit, then work it well into the joints so that it gets behind the tile. This may work if the tiles cant be removed. I have done this on partially blown floor tiles, and it worked well, but never tried it on a wall.

 

[digga_23]

I've just thought of another option that may work, but I cant guarantee it and it will probably be messy. We sell a 3 part epoxy grout, you could mix up the base liquid and the accelerator, add a little of the sand to bulk it out a bit, then work it well into the joints so that it gets behind the tile. This may work if the tiles cant be removed. I have done this on partially blown floor tiles, and it worked well, but never tried it on a wall.

What is it called?


I was looking at something with a gun to get in between the holes like:
1.) Gorilla glue (then spray a mist of water in after), but think will be messy
2.) Water proof gorilla expanding foam (as that will definitely penetrate the full area and get behind the tiles and won't need much. but does have risk that it may push tiles out (although likely difficult as shower is holding it in place)
3.) A strong grab adhesive that can stick to tiles like "gorilla glue grab adhesive", but i think i'll need to pump several guns worth in to the tiles.

Just wondered if any one had personally done something similar.

 

[Jon_Hall]

Sorry I have only used epoxy, I cant recommend an expanding foam or anything like that.

 

[digga_23]

Just to help close this out for any others that may have a similar issue. and don't want to dismantle there whole shower quadrant! - 2 tiles that hada small amount of flex and are being banged by a shower door, resulting in a hair line crack to form in the grout on 2 of the tiles after 5-6 months at a time. Believed not sufficient adhesive was originally applied and small section may have de-bonded

I went with gorilla grab adhesive, i grounded out the existing grout, squeezed the end of the nozzle to fit through the gaps and injected grab adhesive all round the 2 tiles that were giving some bounce (believed part of the tile had de-bonded and there wasn't adhesive going all the way to the edge that may have caused this).
This stuck it very well to the wall and there is no longer any flex as the gap is also filled. S

I've now ordered some white "bal - microflex" grout as this offers a bit more flexibility for any small movements ( in case the shower quadrant door smashing shut on the tile may still cause a hairline crack again).
Probably didn't need to do both, but may as well go with belt and braces to save doing anything again.