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