Tiles falling off 12mm ply....

[jonty1]

Hi All,

I've got a problem with tiles coming off in a shower (my own) having been tiled onto 12mm ply. I built it, and being a carpenter used 12mm ply thinking I was doing the right thing to stabilise the stud walls. The tiler said it was ok to tile onto and used SBR to prime it and tiled away.... Now 3 years later the shower is unusable because it leaks to the floor below. The tiles are not falling off yet, but are coming free from the ply and would all pull off like a piece of cake if needed, the grout is cracking away now too...
It's a 900 square tray with stud walls left, right and rear and a front pivot door, which has about 10mm play to reduce in size if I was to overboard the ply with anything.
My question is, can I take off the tiles and board over the ply with 4mm wedi board screwed at very regular centres to the ply and re-tile the cubicle?
Would 4mm be too thin?
Is there anything similar that I could use but cheaper, or could I re-seal the ply with anything different and re-tile it?
I'm trying to avoid removing the ply as well and replacing completely with thicker backer board for reasons of lack of my spare time and the mess and making good involved. However I am limited to adding about 4mm either side, (That's still going to be tight) because the door only has minimal adjustment left on the side tracks to go any smaller...
Any comments or ideas to resolve this little problem greatly appreciated please!
Thanks,
Jonty

 

[Andy Allen]

what state is the ply in..? if its been leaking for a while i should think its not in very good condition..

 

[kilty55]

the ply should not be there in the 1st instance now its water damaged no doubt i would definately remove it completely and re sheet before it damages another part of your house

 

[The D]

Now you have don it wrong once and it has not lasted I would say learn from your mistakes and do it properly. Yes you could over board with 4mmWedi but your ply is probably soaked if you stop the ply from getting wet it will start to shrink as it dries out and you will have just as many problems.
You could leave the ply to fully dry before gluing and screwing the 4mm Wedi but if you did not prime the back and the edges of the ply before it was installed you could still have problems.

If it was me I would remove the ply re-board with Wedi or Hardie and live knowing I have done it right and I will not be doing it all over again in 1,2or 3 years

 

[Colour Republic]

Come on you're a chippy, ripping it out and replacing won't be too much bother even if you have to add noggins in order to allow you to not have to cut past the shower where you may have had to make good after. Working on your own home is always a pain after doing somebody elases all day but get it done man!

I would replace with 12.5mm plasterboard then tank with a paint on solution, that way you won't have a difference in levels with areas out side of the area you need to re-tile

 

[The D]

Come on you're a chippy, ripping it out and replacing won't be too much bother even if you have to add noggins in order to allow you to not have to cut past the shower where you may have had to make good after. Working on your own home is always a pain after doing somebody elases all day but get it done man!

I would replace with 12.5mm plasterboard then tank with a paint on solution, that way you won't have a difference in levels with areas out side of the area you need to re-tile

Got your builders hat on then m8 12.5mm plasterboard:yikes: in a wet area if you are going to do it do it right :incazzato:

 

[Colour Republic]

Got your builders hat on then m8 12.5mm plasterboard:yikes: in a wet area if you are going to do it do it right :incazzato:

Tanked Deano, tanked

My favorite of the paint on systems has to be the Ardex one. Tough as old boots and doesn't look like you could peel it off like some do. For years a local tile merchant had tanked the inside of the cardboard box the kit comes in, cut a plastic window in the side, filled with water and floated a rubber duck in it. It was on the counter for years like that and for me was good enough to show it works.

If I use backer boards on the wall I always use far thicker than 12mm as i just feel they have too much play in them, then in a wet area you still have to joint them, Not saying you shouldn't use them or can't it just doesn't sit that well in my head because of the play in the thinner range, so for me plasterboard tanked in a shower is prefered as in most cases you can do the whole area without any joints save for the internal one. Tanked of course.

 

[The D]

Tanked Deano, tanked

My favorite of the paint on systems has to be the Ardex one. Tough as old boots and doesn't look like you could peel it off like some do. For years a local tile merchant had tanked the inside of the cardboard box the kit comes in, cut a plastic window in the side, filled with water and floated a rubber duck in it. It was on the counter for years like that and for me was good enough to show it works.

If I use backer boards on the wall I always use far thicker than 12mm as i just feel they have too much play in them, then in a wet area you still have to joint them, Not saying you shouldn't use them or can't it just doesn't sit that well in my head because of the play in the thinner range, so for me plasterboard tanked in a shower is prefered as in most cases you can do the whole area without any joints save for the internal one. Tanked of course.

I disagree with that m8 IMHO plasterboard has no place in a wet area if at all possible backer boards are the way to go. As for not being ridged enough I don’t know what brand you are using but I would put 10mm Wedi or 12mm Hardie over 12.5mm plasterboard for strength and suitability any day of the week

 

[Colour Republic]

I disagree with that m8 IMHO plasterboard has no place in a wet area if at all possible backer boards are the way to go. As for not being ridged enough I don’t know what brand you are using but I would put 10mm Wedi or 12mm Hardie over 12.5mm plasterboard for strength and suitability any day of the week

Fair enough mate.

But if plasterboard is tanked (correctly!) it ceases to be plasterboard any more wouldn't you agree? I fully accept that backer boards have the added benefit of taking more weight than plasterboard but as for water resistance I don't think there is anything in it.

Fully prepared to change my mind if you can you can show the error in my thinking

Marmox BTW

 

[jonty1]

Thanks for the replies chaps, it looks like the best way will be to have the lot out and redo with backer board. I haven't seen the state of the ply yet as I haven't taken the tiles off, but it should be dry since the minute I saw it leaked it's never been used since.
Colour Republic, if you can tank cardboard with Ardex, can I tank the ply if it is dry and in good nick and re-tile it?
Cheers,
Jonty

 

[The D]

Fair enough mate.

But if plasterboard is tanked (correctly!) it ceases to be plasterboard any more wouldn't you agree? I fully accept that backer boards have the added benefit of taking more weight than plasterboard but as for water resistance I don't think there is anything in it.

Fully prepared to change my mind if you can you can show the error in my thinking

Marmox BTW

I some countries plasterboard is illegal in wet areas as the mold that can grow on it in damp conditions is highly toxic. Baker boards are water resistant in there own right and in some cases water proof but will still need tanking on the joints and fixings. for a belt and bracers approach tank the lot

 

[DHTiling]

I agree with deano , but we are just tilers Dean , what do we know :lol:

 

[The D]

Thanks for the replies chaps, it looks like the best way will be to have the lot out and redo with backer board. I haven't seen the state of the ply yet as I haven't taken the tiles off, but it should be dry since the minute I saw it leaked it's never been used since.
Colour Republic, if you can tank cardboard with Ardex, can I tank the ply if it is dry and in good nick and re-tile it?
Cheers,
Jonty

The answer is yes you can. You can also stick the tiles on with Blu-Tack the real question is how long do you want the installation to last

 

[Colour Republic]

I some countries plasterboard is illegal in wet areas as the mold that can grow on it in damp conditions is highly toxic.

Fair point Deano and a good one. Although if as I say the PB was tanked correctly then there is no reason why it would become damp or humid behind the PB

Jonty ply is 'tankable' but in all honesty when you remove the tiles I doubt it's going to be in a fit state regardless of if it's dry or not.

I'd be interested to see if you know if/how and with what the ply was primed with prior to tiling?

 

[The D]

Fair point Deano and a good one. Although if as I say the PB was tanked correctly then there is no reason why it would become damp or humid behind the PB

Jonty ply is 'tankable' but in all honesty when you remove the tiles I doubt it's going to be in a fit state regardless of if it's dry or not.

I'd be interested to see if you know if/how and with what the ply was primed with prior to tiling?

Ok so what is the benefit of using plasterboard other than the fact it is cheap

 

[Diamond Pool Finishers]

Well i'am with Dean on this one, just can't see the point of using any form of wood/plasterboard and there are even more specialist plasterboards out there for this if you want to go looking for them, as he says you still have to tape and tank joints for a 100% job ( i suppose its the fact that dry -gypsum's worst enemy is moister /water the makes me think like this ) but why go there when you don't have to ? sorry

 

[Aston]

people always assume that if plasterboard is tanked then the problems solved but mould can form on the back of the board due to variations in room temp, condensation from the pipes etc and that can affect its integrity..

its easy to think nah, that wont happen but it does and we are moving forwards in technology and building methods so i'd go for a suitable tile backer board ie wedi / marmox/ dukka / kerdi board in a water sensitive area.

if i was forced into using a plasterboard, then i'd use a foil backed board, mechanically fixed and then tanked using a similar system to what colour rob has mentioned..

 

[widler]

So plasterboard which has been used for decades and everybody who has used it and tiled it with no problems at all have been wrong ?
Sorry i disagree really, yes its junk if it gets wet, but why would it get wet if tiled right?
I knocked one off the other month, not a damp spot in sight!
No mould, been tiled since the 80s, is this just a fluke ?

 

[The D]

So plasterboard which has been used for decades and everybody who has used it and tiled it with no problems at all have been wrong ?
Sorry i disagree really, yes its junk if it gets wet, but why would it get wet if tiled right?
I knocked one off the other month, not a damp spot in sight!
No mould, been tiled since the 80s, is this just a fluke ?

If you think it is ok then you do it and you can give the advice you think is right and I will give the advice I think is right but pleas do not try and tell me that there have been no problems with plasterboard in wet areas we both know that is not the truth

 

[The D]

The same question to you widler so what is the benefit of using plasterboard other than the fact it is cheap

 

[SJPurdy]

tanking plasterboard is good at preventing water damage from water that finds its way through the grout but behind the plasterboard there will be pipes with joints made by plumbers and when these leak the tanking will not prevent the plasterboard being soaked from the back- the plaster board will fail and so then will the tiling and the conclusion will be it is the tilers fault. If however a water unaffected tile backer board is used and the joints sealed then the leak from the pipe will not affect the tiling and if discovered the leak will be blamed on the plumber not the tiler.
The plasterboard may be the cheapest option but add to its cost that of a tanking kit and the time to apply the tanking then it will not be that much cheaper (especialy if you get a leak behind it).

 

[The D]

No one coming in with the big benefits to using plasterboard in wet areas?? no surprise there

 

[DHTiling]

Would i use plasterboard when tanking with a tanking paste and give 100% guarantee ..NO..


Would i use PB when tanking a room with membranes.. YES..

Why .? because i can guarantee it is water proof but with a paste i cannot...

 

[The D]

I just do not see the point if you have a chance to do the job from scratch why the hell would you choose plaster board over all the other materials out there that will do the job 100 times better??????????????????????????????? will some one pleas enlighten me

 

[DHTiling]

Ahh from scratch .. that is different dean .. but if not then membranes do work just fine..

Agreed ?..