Cut ceramic tiles cracking after adhesive is set

[mdv]

Hi guys,

Been reading the helpful advice here but now need some of my own!

I had a tiler in to do my bathroom and long story short he started then disappeared citing family problems. Not much I could do except carry on where he left off and decided to finish myself as had all the tiles and adhesive and a free weekend.

No I have followed the same lines he set out which is proving difficult around the window. I am using 600x300x9mm ceramic tiles.

Basically it works out that around the window i need to cut a 49mm cut about 250mm into a 600mm wide tile. So I am left with a tile with a thin cut edge along the bottom. The cut is not the problem I have cut the tile and laid it, however after the adhesive has set the tile has cracked out from where the two cuts meet. Now this has happened both sides of the window so seems to be either the tile or the adhesive.

It is tiled onto a plastered and primed wall and using bal CTF4 adhesive.

It is not due to movement in the wall as this is solid and the tile cracked between 24 and 48 hours after laying. So I am assuming that as the adhesive is setting it is pulling the tile apart slightly and causing a fracture. Does this sound right?

Finally if someone knows how and why this is happening how do I stop it happening again?

Many thanks for any help given!

Matt

 

[White Room]

Do you mean cracking on both right angles of the window cill....

 

[mdv]

Yes at the point where the cuts join! I am cutting a square out of the corner of the tile but it's leaving a 49mm strip along the bottom edge and then approx 315mm of full tile!

 

[White Room]

Thats quite a weak area especially with such a thin cut on a tile and also the plaster sometimes cracks there if it's a float and set in older property's due to movement.

 

[mdv]

The crack that is appearing is very thin and starts at the corner if the cuts then diagonal to the base of the tile. Due to the way the window cill has been raised I can only fix tile adhesive to the lower half of the cut strip of tile so even though the strip is 49mm high adhesive only covers the lower 20-25mm of the tile.

Hope this makes sense!

 

[mdv]

Thats quite a weak area especially with such a thin cut on a tile and also the plaster sometimes cracks there if it's a float and set in older property's due to movement.

Thanks for the reply.

I thought it was quite weak. Is there anyway around it? Flexible adhesive? Or do I have to get more drastic?

 

[Stef]

If it's only 49mm I think it will probably always break.
Make them extra grout lines to try & take your eye off of it..

 

[mdv]

If it's only 49mm I think it will probably always break.
Make them extra grout lines to try & take your eye off of it..

To add to the complication it is a brick pattern and if I add it as a grout line it will be offset from the below grout line by approx 20mm! So will prob look awful!

 

[White Room]

You could do 2 diagonal cuts from the corners of the cill to corner of the tile your fixing or use some fleece tanking membrane under the tile on the weak area...

 

[Dave]

How thick is the adhesive bed ?

 

[mdv]

You could do 2 diagonal cuts from the corners of the cill to corner of the tile your fixing or use some fleece tanking membrane under the tile on the weak area...

Diagonal cuts seems interesting, although I am struggling to picture how it would work?

 

[mdv]

How thick is the adhesive bed ?

Would say it is approx 3-4mm!

 

[Spud]

can you upload a picture ?

 

[Time's Ran Out]

Is the wooden cill still in place but cut back?

 

[mdv]

can you upload a picture ?

i will try and upload a picture later when I'm home!

 

[mdv]

Is the wooden cill still in place but cut back?

No the wooden cill has been removed and plasterboarded level with the intention of tiling around the whole window cill and reveals. I could potentially raise the cill another 15mm which I guess would make the tile stronger as the cut strip would be thicker!

Any tips on strengthening the tile? I was thinking maybe glueing a metal strip along on the back of the tile and then laying the tile with the aim that the legal strip would ensure the tile doesn't get pulled apart and crack during the setting process!

This might be a really stupid idea but I'm trying to avoid taking off several rows of tiles

 

[Time's Ran Out]

Build up the cill and give yourself a bigger 'L' piece.

 

[AliGage]

I would suggest as John said. Raise the cill. Maybe scrim tape around any plasterboard joins and coat in a thin layer of adhesive before fixing the tile again.

 

[Perry]

try under cutting the tile it could be a stress fracture.

 

[mdv]

try under cutting the tile it could be a stress fracture.

thanks got the advice! Although under cutting the tile has me a little confused

 

[Perry]

thanks got the advice! Although under cutting the tile has me a little confused

put a small cut in the corner on the back of the tile.

 

[Dan]

Just bumping some of the older popular (sometimes not so popular) threads. Probably wont be current discussion these days but I just need to do it. So just ignore the thread if it's not current for you.