Hairline crack on the shower tile grout

[tailwind]

There is a tiny hairline crack in between two tiles on the grout on the side where the shower unit is installed. It is at the bottom of the shower near the shower tray. It was fixed once but it has come back. If I push the tile, it appears to be moving a little. There is plywood behind it.

Can I get away without doing anything? If not, do I have to take the grout out and reapply fresh grout. How do I stop the movement of the tile?

Thanks in advance.

 

[Richard C]

There is plywood behind it.

That’s probably the cause of your problem but there could be other factors.

Can I get away without doing anything?

Nope, afraid not; well you can for a while but it will just get worse, probably beyond redemption if not already so.

If not, do I have to take the grout out and reapply fresh grout.

That won’t cure it; it will only patch it up for a short while.

How do I stop the movement of the tile?

Take that tile & all the others surrounding it off the wall, you may be unpleasantly surprised at what you find; what’s going on behind there will dictate what you will have to do next. Post back with photos if you wish, it can make things easier.

 

[tictic]

all of the above...^^.....

 

[1john]

Does the grout go black? It is possible that the ply has rotted behind

 

[tailwind]

This is fairly new shower in the loft conversion we did last year. It is not used often. I tried to use it once a week to keep the negative head pump going. I went behind the plywood and didn't see anything untoward. I don't think the ply is rotten or anything.

What's my next move?

 

[Richard C]

I went behind the plywood and didn't see anything untoward. I don't think the ply is rotten or anything.

Do you mean behind the tiles or behind the wall? Looking at the back of the ply won’t tell you anything, you need to see what’s going on under the tiles.

What's my next move?

Take that tile & all the others surrounding it off the wall, you may be unpleasantly surprised at what you find; what’s going on behind there will dictate what you will have to do next. Post back with photos if you wish, it can make things easier.

What type of ply was used (why oh why did you use ply)? Was it tanked before tiling? What type & size of tiles are they? What adhesive & grout was used?

If it’s a newish shower, the sooner you tackle this the more likely you are to be able to salvage the situation; for a while at least.

 

[1john]

Here is a photo of a shower install that had a bit of cracking and the grout was going a bit black.

Untitled

• 1john
• 2 Apr 2011
• 2

[/img]

 

[Richard C]

Here is a photo of a shower install that had a bit of cracking and the grout was going a bit black.

Untitled

• 1john
• 2 Apr 2011
• 2

[/img]

I know what can be lurking behind there & I’ve had many bad ones but that's incredible ; as bad if not worse than anything I’ve ripped out. Any history? How long had it been in service? What was the tile base?

 

[1john]

12mm wbp ply, been in service for 5/6 years, in a student house though, albeit a very upmarket one, possibility of it being used 10 times a day is the girlies in there each showered twice a day. The ply could be squeezed like a sponge. I used aquapanel and tanked it too for rectification.

 

[tailwind]

I went behind the plywood and didn't see anything untoward. I don't think the ply is rotten or anything.

Do you mean behind the tiles or behind the wall? Looking at the back of the ply won’t tell you anything, you need to see what’s going on under the tiles.

I went behind the ply. The plys are on the stud wall. The builders did it, with some waterproofing material on them. I thought that's normal on stud walls.

What's my next move?

What type of ply was used (why oh why did you use ply)? Was it tanked before tiling? What type & size of tiles are they? What adhesive & grout was used?

I am not sure what ply was used. I can ask the builders and post you an update tomorrow.

The adhesive used was Granfix flexible and the grout used was BAL Superflex Grout.

If it’s a newish shower, the sooner you tackle this the more likely you are to be able to salvage the situation; for a while at least.

I am including a couple of images I've taken of the cracks:

[/img]

Crack1

• tailwind
• 3 Apr 2011
• 1

Crack2

• tailwind
• 3 Apr 2011
• 1

 

[1john]

Tap the tiles, see if they appear loose, the adhesive may have not bonded. When it was re-grouted, did the old grout get raked out to a good depth near or too the plywood or was some new stuff just smeared over? dont take too much notice of the picture I posted, that is an extreme case.

 

[tailwind]

Tap the tiles, see if they appear loose, the adhesive may have not bonded. When it was re-grouted, did the old grout get raked out to a good depth near or too the plywood or was some new stuff just smeared over? dont take too much notice of the picture I posted, that is an extreme case.

I wasn't there when it was done. But I can say with 90% certainty that it was smeared over, the old grout wasn't raked out. The tile doesn't appear to be loose, but the tiles on either side have very small movements.

 

[1john]

You could try raking out and re-grouting properly, you can get a grout rake from wickes for a couple of quid which will do you although if the tiles are moving then you may find yourself removing them and having a look from the tile side. It sounds as if they havent bonded properly, this can be a problem is adhesive is combed on and the tiles fitted a bit to late after when the addy has skinned a bit.

 

[Richard C]

I went behind the ply. The plys are on the stud wall.

As I said looking at the back of the ply will tell you nothing about what’s going on under the tile. [/quote]

The builders did it, with some waterproofing material on them. I thought that's normal on stud walls.

If only that were the case . What sort of waterproofing material? An SBR primer will seal the surface but it won’t make it waterproof to the degree that tanking will. SBR or acrylic primer should always be use on the back & edges of ply but the tile surface needs tanking or you will eventually end up with the mess you see in 1john’s pics. Ply was used a lot in the past but it’s old fashioned, not particularly easy to cut & work with, is not dimensionally stable when it’s damp/wet (which causes tiles to delaminate & cracks), should be sealed on the back & edges against moisture ingress & the tile surface should be tanked. Some use Moisture Resistant plasterboard in shower enclosures but that will still turn to mush if water gets in & should also be tanked in wet areas. Taking all this into consideration, it’s easier, quicker & probably cheaper to use a decent waterproof backer board which will accept heavy tile weights & requires no further treatment before tiling.

I am not sure what ply was used. I can ask the builders and post you an update tomorrow.

It’s important; only WBP ply should be used which uses waterproof adhesive in construction; the standard stuff & will fall apart if it gets wet.

The adhesive used was Granfix flexible and the grout used was BAL Superflex Grout.
The product brands are OK but it’s not really good practice to mix & match. There is always a risk of incompatibility & apart from anything else it will probably invalidate the manufacturers warranty; this may be your last port of call if all else fails but products must be used strictly in accordance with warranty conditions. Which addy was used; I assume it was cement powder not tub mix?

If it’s a newish shower, the sooner you tackle this the more likely you are to be able to salvage the situation; for a while at least.

I am including a couple of images I've taken of the cracks:

I reiterate; you must remove at least the tile & any others that are loose. It’s already been re-grouted & failed again; if it’s just a failure of bonding on that particular tile (not a good sign in itself) just raking out & shoving new grout in there isn’t going to cure it. If the tile is loose & moving, the grout will just crack open again. If you’ve been running the shower with it like that, water will have wicked into the cracks & I will guarantee it will be wet behind there, even if the rot hasn’t yet set in. I’ll say again, if you remove the tile now & all appears well behind, let it dry out for a few days, stick the tile back (with the correct adhesive) & re-grout; if you do this you may salvage the situation, if you dontl it will only get worse.

 

[tailwind]

Ok, I'll try and remove the grout and the tile. How do I remove the tile safely without damaging it?

Thanks.