# Forum Forum Help Desk Introduce Yourself  Yellow Tongue & Wet Areas

## freewheelin

Hi All 
We have recently renovated our main bathroom and replace the old shower cubicle with a lovely walk in shower.   
We employed a builder and tiler separately and we did a lot of the labouring work as directed by the builder and the tiler. 
The new bathroom floor was yellow tongue that we were told was water proof by the builder and we could just water proof on top of which we did (2 x coats bostick grade 3 waterproofing). The tiler then came and tiled and the new shower screen was installed. All good so far. 
The about 6 weeks ago (2 months after the completion of the renovation) we noticed one of the tiles was raised and grouting cracked. We called the tiler who has returned and lifted the tile and said there is moisture underneath onto the yellow tongue. He has advised that we should have put down a membrane, at least, before the waterproofing!!!!!!!!!!! Neither the builder nor the tiler advised us to do this? We would've also insisted on cement sheeting had we known. 
Anyway now we have to fix the problem in the shower.  
Any suggestions as to how to make the walk in shower floor water tight without destroying the entire bathroom floor? 
We are devastated and at a loss as to the best way to rectify the problem!!

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## phild01

It was not a good thing using yellow tongue, but having said that my suspicion falls on the shower screen installation. Were there any screw fixings used under the glass panel or support brackets.

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## sol381

Its fine to use yellow tongue,I use it all the time, but you must use tile underlay over the top.. Sounds like the waterproofing failed as well.. I would have thought the tiler would have done the waterproofing.. Doing it yourself is never a good idea. 
How thick was the tile bed ?

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## freewheelin

Thanks for your input folks. 
phild01 - can you explain the problems/issues you see with using yellow tongue? 
sol381 - what is the underlay you are referring to - what thickness is it and also any particular brand? 
At this stage we can only see 2 options: 1) ripping up wet area (walk in shower area) and applying membrane then water proofing and then re-tiling OR 2) Ripping up all bathroom tile, roving shower screen then applying membrane, cement sheeting or underlay, water proofing then re-tiling. 
Does anyone have any thoughts or alternatives to this?  HELP

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## droog

Waterproofing is the membrane, are you referring to the reinforcing bandage needed at joins and junctions ?  
Problem is that if there is no water stop angle under the membrane then any water under the tiles will potentially flow under the tiles anywhere in the room, making removing only the shower and redoing problematic.
Was any slope built into the floor or was a screed used to get the fall ?

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## phild01

> Thanks for your input folks. 
> phild01 - can you explain the problems/issues you see with using yellow tongue?

  Precisely the problem you have, when something goes wrong it goes badly wrong. Recovery with Scyon or compressed cement sheet would be much easier being water resilient. I also see little benefit using tile underlay over particleboard.  
In the early days of particle board flooring, you didn't use yellow tongue but a more water resilient red or green tongue (trying to remember if it was red or green), then an epoxy coating with flashed joins. This was screed over directly.  Ideally a shower tray was always used usually copper. One of my bathrooms is done that way and been perfect for 30 years.
 Houses are generally made with little regard to frame movement and if it is excessive the waterproofing can fail. Whether that is your issue would be hard to say with what you have provided.

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## freewheelin

Hi droog 
Regarding membrane I am referring to either the paint on type or the roll on type before the water proofing. The slope was built into the floor.

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## freewheelin

Phild01 - my house is not new but the bathroom now is. I guess what I really need to know is the best long term fix to my issue. If I just use Acton or cement sheeting in the walk in shower this will raise that tiled section by 10-20ml thus making it uneven with the rest of the bathroom? Also with my current set up (yellow tongue, waterproofing & tiles) could movement be an issue?

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## phild01

> Phild01 - my house is not new but the bathroom now is. I guess what I really need to know is the best long term fix to my issue. If I just use Acton or cement sheeting in the walk in shower this will raise that tiled section by 10-20ml thus making it uneven with the rest of the bathroom? Also with my current set up (yellow tongue, waterproofing & tiles) could movement be an issue?

  Identify what went wrong and correct it. I suggested one area of investigation being any shower bracket penetrations through the waterproofing. I understand you have done the waterproofing, did you use bond breaking as allured to in Droog's post. All intersecting planes of the walls and floor need this, if not done breaching is imminent. It must be done generously as does the general application of the waterproofing, so were the correct methods used to do this. The particleboards also need bondbreaking where they meet.  
To correct your situation you need to identify the mistakes and not repeat them. One area I think needs special mention is how tight the wall and floor framing is, none of this should be flexing and that is also dependent of how well it is all founded. 
In your case we don't know how damaged your particleboard or wall framing is. That type of board can really soak up the water and the waterproofing holds it in. The board loses it's rigidity and becomes permanently damaged. That needs to be assessed. From what you have given it may ultimately mean lifting the substrate and tiles and redoing it all. I would start by removing the shower floor tiles and investigate. You say you don't want to lift your floor tiling but do consider that fixing the shower floor area only may not stop water tracking across any waterproofing you reinstate and re-entering the substrate outside this. Regard also needs to be given to any reinstated waterproofing and how it will be integral with your shower walls.  
Another option is a shower tray but that will need a hob and maybe a new shower enclosure. 
Replacing the shower floor with cement based products does not mean a floor height difference as the particleboard is actually replaced by it.

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## droog

What I was saying is that I think you are misunderstanding the products used and what was / is required. The stuff you paint or roll on is waterproofing membrane, there is no separate waterproofing you put on top of the membrane it is one combined system. 
From your description this sounds like the stuff you are referring that you used: https://www.bostik.com/australia/Bos...-Waterproofing 
It is waterproofing membrane, you use it in conjunction with bandage and bond breaker for the system. 
For anyone to assist you they need to understand what steps you did in applying the above waterproofing membrane, from there someone may be able to tell you what you left out. Did you use bandage and bond breaker as stated in the instructions? How was the fall in the shower formed, is there fall outside the shower ? Was a water stop angle fitted at the shower or doorway ? 
At the end of the day the tiles need to be ripped up to address the issue and confirm what has failed, you can also get under the house and see if there is visible damage outside the shower area.

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## sol381

If you have to rip it up and redo it , which i think you may have to, either get a qualified waterproofer or the tiler to do it.. waterproofing is THE most important thing in wet areas. If you waterproofed directly to yellow tongue then it has to come up.

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## METRIX

> Hi All 
> We have recently renovated our main bathroom and replace the old shower cubicle with a lovely walk in shower.   
> We employed a builder and tiler separately and we did a lot of the labouring work as directed by the builder and the tiler. 
> The new bathroom floor was yellow tongue that we were told was water proof by the builder and we could just water proof on top of which we did (2 x coats bostick grade 3 waterproofing). The tiler then came and tiled and the new shower screen was installed. All good so far. 
> The about 6 weeks ago (2 months after the completion of the renovation) we noticed one of the tiles was raised and grouting cracked. We called the tiler who has returned and lifted the tile and said there is moisture underneath onto the yellow tongue. He has advised that we should have put down a membrane, at least, before the waterproofing!!!!!!!!!!! Neither the builder nor the tiler advised us to do this? We would've also insisted on cement sheeting had we known. 
> Anyway now we have to fix the problem in the shower.  
> Any suggestions as to how to make the walk in shower floor water tight without destroying the entire bathroom floor? 
> We are devastated and at a loss as to the best way to rectify the problem!!

  I think you have confused what you might have been told.
Waterproofing is the membrane, there is no membrane that needs to be put on before the waterproofing. 
The only thing that goes on before a membrane is a primer. 
You have made a few mistakes as follows. 
1: Using Raw YT in a wet ares is not a long term solution if anything goes wrong (as you are finding out), it doesn't take long to completely stuff the YT.
yes you can use it, I never do, there are plenty of suitable products such as Scyon, Durafloor or others that "are" waterproof, Yellow Tongue is NOT waterproof. 
See below a pic I took the other day, this is from a failed build, the YT and Scyon have been exposed to the weather for too long, as you will see how much the YT has shrunk right next to it is Scyon, it has not moved, also the YT was completely stuffed, if you walked on it, your foot would go right through it. that gap you are seeing is 25mm. 
2: You did the waterproofing yourself, this is something that should be done by a professional that will offer you a guarantee if something goes wrong, if you are noticing problems after 6 weeks then the problem was there from day one. 
Waterproofing is not about simply putting a membrane on and forgetting about it, it's about putting it one properly and attention to detail, if you have never done it before you won;t know what detail needs to be adhered to, I have seen plenty of DIY waterproofing failures which ended up in having to rip up all the flooring and most of the walls to re apply the waterproofing properly from scratch then re tile, so any money the owners thought they saved by DIY the waterproofing, they lost 10 times as much having to do the job properly the second time, I have said it many times on here waterproofing is not a DIY job. 
Unfortunately there is no quick / cheap fix for this, I know you don;t want to hear this, but most likely the floor will have to come up and be re done properly. 
Out of curiosity, the Builder what part did he play in the renovation, I don't know any builders that will do a bathroom reno and have the owner do the waterproofing, if he did this is madness.   Attachment 124865  Attachment 124866

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## freewheelin

Thanks for all your feed back and helpful information. 
We have decided that the best option to ensure that the job is done properly this time is to remove shower screen rip up the tiles and redo the floor. 
The question is with what? 
We are srongly leaning towards leaving yellow tongue and using a product - Multipanel Water Shower base kit then re-tiling - Any feedback? 
Alternatively we will apply membrane to the yellow tongue then cement sheeting then retile -  (using a tile over shower base) -Any comments? 
Thanks

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## phild01

I would dismiss using tile overlay over the existing particleboard but up to you. Also the walk in shower may end up higher than the existing floor level, depending on the screed gradients. If you are going to rip the tiles up then take the particleboard with it as it may have permanent damage and very little rigidity. Be careful that just doing the shower area may create issues with water tracking across the bathroom floor (and up the shower walls). A shower tray may well be your better option as I thought earlier.  Take care doing this again, you don't want a repeat of unexpected problems.

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## droog

Yellow tongue is a recognised flooring and can be used in bathrooms, if starting from scratch a compressed cement sheet is a better alternative. The yellow tongue is fine and only an issue if the waterproofing is compromised. If waterproofing is completed properly yellow tongue will present no problems.
If the existing yellow tongue is water affected junk it and start fresh. 
It concerns me that you suggest applying a membrane then cement sheet over it, I suggest you study up a lot more on methods and materials that should be used and how to use them. 
If you do not fully understand what is required I strongly urge you to get a professional in otherwise you will probably be tearing the floor up again within the next 6-12 months.  
Have not used the multi panel but did use a Universal Shower Base, https://universalshowerbase.com.au/
They are cut into the floor and sit on the joists, most models the base is the same thickness as yellow tongue and 6 mm tile underlay. This means a flat walk in shower.

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## METRIX

> Thanks for all your feed back and helpful information. 
> We have decided that the best option to ensure that the job is done properly this time is to remove shower screen rip up the tiles and redo the floor. 
> The question is with what? 
> We are srongly leaning towards leaving yellow tongue and using a product - Multipanel Water Shower base kit then re-tiling - Any feedback? 
> Alternatively we will apply membrane to the yellow tongue then cement sheeting then retile -  (using a tile over shower base) -Any comments? 
> Thanks

  Durafloor is my choice of product for wet areas, or an equivalent Scyon product. https://bgcinnovadesign.com.au/floor/innova/durafloor/ 
I would strongly recommend you get someone in to do the waterproofing for you, waterproofing properly is a job that required knowledge and an attention to detail, if either of these are missing there is bound to be problems. 
Yes plenty of DIY have done waterproffing with no problems, I would say most of them were due to luck. 
Tearing up bathroom floors a 2nd or 3rd time is not only expensive, it's a waste of materials and an inconvenience.

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