Cracking Tiles!

[kaharrison9]

Hi all
Your thoughts would be appreciated.
Been to look at a wetroom bathroom in an exstension that was built around 7 months ago and has now gone horribly wrong.
The builder whose built the stud walls for the bathrooms hasn't used any noggins and has just got vertical studs that he has then screwed 12/15mm ply upwards at about every 650mm.In a small area that has still to be tiled the end of the ply doesn't even fall onto any wood and as you come up the stairs theres cracks where the ceiling meets the wall.At first thought it was structural but when reached up can actual push the stud wall.
Next,the customer has decided to tile the wet room himself,Used a unknown tubbed addy(tiles 300x100)no tanking at all,grouted into the corner which has now cracked,poor set out,on one wall tiled from the ceiling down for a mirror and when the wedi board was fitted and he has tiled the floor there is now a 3mm step onto the wedi board which he uses a squeege to push the water into the gulley:yikes:
Himself and his wife were woken by bangs and went to investigate and there were 3 4-5ft seperate hairline cracks in the tiling.
He admits he's made a right mess on his part and is looking at it been redone and also wants to avoid a repeat in a second bathroom.
The 3 cracks appear to be where the stud uprights are.
Is the likely cause of these cracks to be temperature/humidity exspansion and contraction where the 2 ply ends meet?or a weak wood frame poorly screwed and there's movement? or any other suggestions.
What's thoughts on having ply on walls especially bathrooms,i would never had considered it but the bal book explains how to tile onto ply?
The reason the builder used ply was he said when tiling onto plaster board the card pulls off and i'm sure he probably hasn't heard of a cement board.
Had the background been differant anybody think the cracks would still have appeared.
Cheers
Kev

 

[White Room]

Everything is wrong, ply on walls, no noggins on studwork, the fixings to ply are to far apart, no tanking, tubbed adhesive and the guy tiling it himself sounds a mess.

Just to add to what you noted, expansion and contraction.

Moisture is getting into the ply and could even be bulging because of the moisture

 

[Colour Republic]

If there is movement in the wall I would hazard a guess that the wall runs parallel with the joists, the wall is in between the joists so has no fixings into anything above apart from the plasterboard on the ceiling, he may have attempted to gripfill the studwork to the ceiling.

Is there a door in the studwork he put up?
Is there a loft space above the wetroom? If so can you add nogins in the loft and fix down onto the studwork from above?

When he's stated that the paper pulls off he might be reffering to later re-tiling, which may destroy the board when stripping but in any case it's a lousy excuse

 

[bluesky]

sounds like it`s all got to come out and be done properly to me .v expensive mistake !😳

 

[Colour Republic]

Hang on a minute just re-read you post, did these cracks all appear one night? How long ago was the extension built, what sort of settlement has occured? are there any cracks to the brickwork outside?

 

[kaharrison9]

It is a mess m8.
Costly to redo but probably start of the problems if left.
Had the stud all been fine,plenty of noggins ,well screwed and plyed do you think cracks would still have appeared?
Never used ply before and the customer is approaching the builder as to accept some responsibility towards the cracks

 

[Colour Republic]

I'm wondering what caused the cracks, if they all relate to the studs then it might suggest the wall was suddenly put under pressure and bowed, but your saying the wall moves freely. I could understand it if someone lent on the wall and it cracked but you say it happened in the middle of the night and was enough to wake them up! So how much has the extension settled? or did it take a big drop when the ground was maybe water logged and the extension dropped.

It does sound like it needs starting again but if it was me i'd like to know why it cracked suddenly rather than over a period of time

 

[kaharrison9]

There's no cracks in the outside brickwork,the exstension was 7 months ago,the cracks are hairline and didn't ask if they happened in one go.
That's why i'm asking about how unstable ply is as there is even a possibility the cracks are from some other facture.
In the other bathroom it's half platerboard/skim where it's to be painted and plyboard.There is no cracks in the skim.
Which is another reason i'm thinking towards the background substrate.
Cheers

 

[kaharrison9]

That's in the back of my mind if there was some sudden movement,the cracks are on 3 of the 4 walls not on the same one.
It confuses things when the prep and the tiling have been poor.

 

[Colour Republic]

If the cracks didn't suddenly happen then it could well be as Whitebeam says due to damp expansion. I would add extra nogins, make sure it is secured at the top, plasterboard then waterproof, or go for a backerboard.

Tiling onto ply walls isn't unheard of but it wouldn't be my choice as it flexs alot and you can buy better products for less money