Help! Tiled wetroom floor looks perfect but grout doesn't dry out!

[Dan]

You're misunderstanding the word 'waterproof' if you think a tiled wall or floor is impervious to water, surely?

EVERY bathroom wall that's not tanked, fails eventually due to the substrate getting wet constantly when it hasn't been tanked. EVERY bathroom wall that's been tanked, and properly using tape onto the bath or shower tray, NEVER fails due to water ingress.

So the tiles are literally never protecting the substrate from water and are literally just there to take the brunt of the 'weathering' (term used loosely) and cleaning and to give the room an aesthetically pleasing look.

Not meant to come across argumentative BTW.

 

[The D]

if the job is done right the background should never get wet not even damp

 

[The D]

dan i have striped tiles that have been on commercial showers for twenty years and the background has never seen a drop of water and as a professional tiler i am telling you that the tiling is the primary waterproofing and the tanking is a secondary failsafe


this misconception of grout letting water pass through it like it's not there is just silly. if the grout is constantly submerged in water for long periods of time like months at a time then eventually the water will penetrate the grout and possibly come in contact with the background. but in a domesick shower with intermittent wetting the water will not fully penetrate the grout unless there are other problems such as cracks or pin holes

 

[Dan]

If you ask BAL technical which dispersion adhesive to use, they'll explain intermittent wetting will not affect their blue star, but regular wetting will (might be wrong on the colour, and I'm sure they don't make that even now?). So they're expecting water to get through. And they're celebrating 50 years of being a "leading brand" this year. So my email today said.

Formers are shaped to allow water to flow down to a trap.

Tanking is designed to allow water to fall into the bath.

There are umpteen products that are not just designed as a backup. They're literally designed to take the water somewhere. As the guys in the white suits know water IS getting through that cement, that's NOT going to stop it.

I appreciate you taking more time to write something decent in the thread though. And perhaps this subject is a matter for a different thread.

But water IS getting behind the tiles here. And due to the amount, I'd say its not just from use. It's from a pipe. The former and the trap are perhaps not doing their job in this case. But maybe they are and it's something else.

 

[Paula]

If you ask BAL technical which dispersion adhesive to use, they'll explain intermittent wetting will not affect their blue star, but regular wetting will (might be wrong on the colour, and I'm sure they don't make that even now?). So they're expecting water to get through. And they're celebrating 50 years of being a "leading brand" this year. So my email today said.

Formers are shaped to allow water to flow down to a trap.

Tanking is designed to allow water to fall into the bath.

There are umpteen products that are not just designed as a backup. They're literally designed to take the water somewhere. As the guys in the white suits know water IS getting through that cement, that's NOT going to stop it.

I appreciate you taking more time to write something decent in the thread though. And perhaps this subject is a matter for a different thread.

But water IS getting behind the tiles here. And due to the amount, I'd say its not just from use. It's from a pipe. The former and the trap are perhaps not doing their job in this case. But maybe they are and it's something else.

Goodness, we seem to have opened up a can of worms here!

It does seem that there is an awful lot of confusion about the roles played by tiles, grout, adhesive and tanking, even among professionals with many years of experience in the industry, so I'm not surprised that it is taking me so long to sort this problem out! I just thought I would try and recap where I think we have got to.....

I had sort of resigned myself to accepting that some water would always get under the tiles while showering, as I had gathered from literature/the BAL rep/forum discussions that cementitious grout is only water-resistant, not water-proof. I would imagine that porcelain tiles are pretty waterproof, so can't imagine much water would be getting through them. However, if this is the case, then why are there not more complaints on the forum of grout never drying out in tiled shower trays? It would seem that there is something different going on in our tray, which could be any of or a combination of these situations:

- more water entering behind the tiles from a leak in plumbing pipework to the shower heads
- large gaps in the grout in the tray leading to excessive ingress of water
- large gaps in the adhesive under the tiles so that water can 'pool' here, without falling down the drain

It seems unlikely that water is getting in from the drain, as this would eventually get through the membrane and on to the ceiling below, which is not happening.

What has been odd is that, having taken out the cementitious grout in the tray, and replaced it with epoxy, which is far more water-resistant, we now have dampness appearing away from the areas which get wet. WE HAVE NOT USED THE SHOWER FOR 4 WEEKS NOW AND THE GROUT OUTSIDE THE TRAY IS STILL DAMP IN PATCHES!

Thanks to all the useful discussion on this thread, it seems that this could either be because water is STILL getting through the tiling in the tray, even when the shower is not in use (from constantly leaking plumbing) OR perhaps because there is water trapped under the tiles and new epoxy grout in the tray, and this is now trying to escape through evaporation across the rest of the floor.

Having seen the results of pressure tests on the shower pipework, and never having seen any dampness on the walls (or, more likely,the ceilings below as our walls are only tanked at the bottom) I would be inclined to discount plumbing issues.

So, that leaves us with the possibility that there is still water under the tray tiles, even after 4 weeks. It could even be possible that this water dates back to the pre-epoxy days, even though we did not use the shower then for about 12 weeks, as even at this stage, we still had damp patches in the shower tray. I am told that it could take up to 6 months for dampness behind tiles to dry out! Now that we have re-grouted with epoxy, this is not helping to disperse any remaining dampness as it cannot escape easily through the epoxy, so it may be trying to escape through the adhesive bed and up through the cementitious grout on the rest of the floor.

We're sort of in limbo, as we feel that we can't do any more testing until we have a completely dry floor. Underfloor heating last week helped to dry the patches a bit, but they reappeared as soon as we switched it off, although they are diminishing slightly overall. If it gets to the stage that they are almost gone, then perhaps we should try re-using the shower, and if they return, we know that water is definitely getting in through the top of the tiling, through the epoxy.

I don't think we can do anything else at this stage.

 

[Dan]

Thanks for the update.

Water can't disperse through epoxy at all. It's impervious to water, bleach, even sulphuric acid, apparently.

I hope you get to the bottom of this. I'd be pulling tiles up by now myself to find the source of the water.

 

[WetSaw]

Just reread your post... No more to add, sorry!

 

[Paula]

Just reread your post... No more to add, sorry!

Thanks! Just thought it was worth re-capping, just in case anyone had any further thoughts or knew of other situations like this.

I'll let you know how we get on!

 

[cbmltd]

I've seen something like this before with mapei plus grout the bottom row on top of the wet floor had been doted and therefor the grout had failed the water was seeping behide the wall tile and under the mosaic wetdeck.
After a week of drying out,removing the base tile,tiling it properly and using an epoxy grout over the whole area.well I haven't been called back .i think the repair was a succes.

 

[Dan]

I've seen something like this before with mapei plus grout the bottom row on top of the wet floor had been doted and therefor the grout had failed the water was seeping behide the wall tile and under the mosaic wetdeck.
After a week of drying out,removing the base tile,tiling it properly and using an epoxy grout over the whole area.well I haven't been called back .i think the repair was a succes.

Have you read the WHOLE thread?

 

[cbmltd]

I've read most of it and alot seems to go around in a circle,I'm just putting my opinion across .The wetroom I was talking about was 3 metres long and water was visable at the end of the deck well away from the shower with a screen in between the two.
Water will travel anywhere if it has a chance to get through the only reason it never went downstairs is because of the membrane underneath.definitely needs taking up and restarting otherwise the problem will persist.

 

[Dan]

Didn't mean What you'd said was wrong or right. Just mean they'd redone it with epoxy. And the problem moved.

 

[cbmltd]

I know they used epoxy but if there's still movement or void behind the wall tile it will still get through I didn't see anyone say they had replaced the wall tiles as well its a disaster hopefully they get it sorted at the builder ,tilers expense.

 

[Paula]

Just thought I'd give an update......

We let the floor dry out for several weeks, had the plumber in to discount any leaks from the supply side (which he did), bought a moisture meter (which showed that the dark patches were indeed damp) and scratched our heads (again).

There is no obvious movement of tiles, either on the floor or the walls, and no cracking of grout. Thinking things through logically, we came to the conclusion that perhaps the water that was appearing beyond the shower screen was indeed the water which had got underneath the shower tray when it was first installed (when there were bits of grout missing round the drain and tiny cracks in the floor grout, before we re-grouted with epoxy). Apparently it can take up to six months for this water to dry out completely, and of course it was having to travel further (beyond the shower screen) to evaporate as we had re-grouted with epoxy in the shower area.

So, armed with moisture meter readings, we started using the shower again.

Remarkably, the damp patches did not become even damper, and, even more remarkably, over time they have completely disappeared. Admittedly, for the past month or so we have had the underfloor heating on, but we also had it on in order to try and dry the tiles in the summer, and it didn't seem to work then. So it appears that, perhaps our theory is right, and that we just had to play a waiting game. In all, it probably took around six months for the water that originally got under the tiles to find its way out.

The epoxy grout seems to be holding up fine, with no signs of cracking at all, and we have made sure that we have a good Silicon seal along the bottom of the shower screen so that the main shower area is entirely waterproof above the tiles. Yes, we still have normal grout up the walls, but if there was any significant ingress of water coming from there, I think we would still have problems with the floor being wet, which we don't.

It is still a mystery to me why so much water was able to get under the tiles in the first place....I can only think that the grouting was done badly, as there was never any movement of tiles on the tray. It certainly never looked really bad, but having been done very carefully with epoxy the second time, we have not had any further problems.

So, as I said before, I am a big fan of epoxy grout in shower trays. Given how easy it is to allow excessive water to get under the tiles and perhaps travel beyond the shower area, I can't understand why it's not standard practice to use it for wet room showers! If we ever have one done again, I will definitely be asking for it over the whole floor of the bathroom.

Of course I'll keep you updated if things change!

 

[p4ulo]

Phew.....nice one Paula....who could have imagined that grouting a shower tray properly would be so important??!! (lol)

 

[Paula]

Phew.....nice one Paula....who could have imagined that grouting a shower tray properly would be so important??!! (lol)

It does seem so (although apart from a few bits of grout missing around the drain, you wouldn't really have been able say that it was done badly). I'm convinced that changing the grout to epoxy has had just as much of an effect....given that normal grout ALWAYS lets water through, why would you want to use anything else?

 

[Paul72]

Hi. I'm new here and have read this thread and could really do with some advice.

I've had a large extension built and now have 2 wetrooms to complete. I have used AKW tuff form and AKW tri form trays.

I'm at the tiling stage now and have been looking at the Mapei Kerapoxy CQ grout. (I have tanked the wet areas with mapei gum and tape) but I was drawn to the kerapoxy due to it being impermeable.

I called mapei tech and they said it has no flexibility once cured do was just wondering if it would be OK to use on the wetrooms floors as one guy states that he uses it on all his wetrooms and has never had any problems.

I'd also be interested to see if Paula's epoxy grout has withstood the test of time since sorting out the problem.

Any feedback would be greatly appreciated

Thanks.

Paul

 

[Paula]

Hi, I don't know whether anyone is still referring to this (very long!) thread, and I'm sure it's too late for Paul, above, but I have some information I thought I should share with you.

I too was told by the technical people at Mapei that epoxy was not as flexible as cementitious grout, but that, unless there was constant movement in the floor, then it should be ok to use it on our tiles which are laid on a suspended timber floor. As there was not a huge amount of movement on our floor, and encouraged by comments on this forum by others who said they usually use epoxy in wet rooms, we went ahead.

About 16 months after the epoxy was applied, I started to notice dark lines along a couple of the grout lines which surround the two tiles we tend to stand on when we shower. Over the following months these lines have got bigger, and they are now full blown cracks. However, they are confined to the area where we stand to shower, so most of the grouting in the shower area is still intact.

Our builder has come to look, and contacted Mapei who have said that there is no flexibility in epoxy, but that the cracking could be to do with any of the following:

- excessive movement in the suspended timber floor under the tray (ply not screwed down properly)
- failure of the Impey tanking
-water/moisture seeping to the ply in the flooring and making it swell

We haven't noticed any leaking in the ceiling below so would be surprised if the Impey tanking had failed.

He is asking what I want to do, but is suggesting that the epoxy is almost impossible to remove without damaging the tiles.

I'm really not sure what to say! Obviously I'm disappointed that the epoxy has failed, given that it seemed like the perfect solution to our problems for over a year, but I still consider the bathroom "new", so am not happy that the shower area has large cracks. Long term, I don't imagine it's a good idea to let water soak down these cracks, even if there is intact membrane underneath?

Any ideas anyone? Should I push for removing the epoxy and replacing it with normal grout, given that we eventually worked out that the original problem (permanently wet grout) was down to the tiler leaving a void around the drain that filled up with water, and that has now been rectified? or do you think that we'll eventually end up with cracked grout, whichever is used, as there is obviously movement in our floor?

 

[Bill]

By the time this gets resolved, your tiles will be out of fashion and you will want a 'new look' for your bathroom.........

 

[Italy]

I used a hot air gun.
To remove epoxy.
Pay attention to the wood below. It could burn.

 

[LM]

Bloody hell, just read this thread 😵

 

[SJPurdy]

We haven't noticed any leaking in the ceiling below so would be surprised if the Impey tanking had failed.

I don't think it is at all likely to fail as a tanking barrier to stop water getting through, (I haven't tried the newer easier to use version so am assuming it is similar to the old). However it is my opinion that it remains slightly compressible under the tiles and this may be why the grout is cracking around the tiles that are stood on most.

 

[J Sid]

have you any spare tiles?
if so lift the tiles with the grout cracking, there will be water under them now so will need drying out. When you remove the tiles you will be able to investigate further to what's going on.

 

[Paula]

have you any spare tiles?
if so lift the tiles with the grout cracking, there will be water under them now so will need drying out. When you remove the tiles you will be able to investigate further to what's going on.

Thanks for that, Julian.

I'm just wondering how easy it will be to remove tiles? It's not like they're obviously wobbling about, and the epoxy grout looks well and truly stuck to at least some of the edges. Should we be worried about damaging the membrane in the process?

 

[Paula]

I don't think it is at all likely to fail as a tanking barrier to stop water getting through, (I haven't tried the newer easier to use version so am assuming it is similar to the old). However it is my opinion that it remains slightly compressible under the tiles and this may be why the grout is cracking around the tiles that are stood on most.

So are you saying that you think with Impey membrane there will always be some movement of tiles? How can we stop the cracking happening, then?

 

[Rob-Bob]

Hi Paula,
I've just done wetroom and used porcelanosa 'swimming pool' grout (the one which you mix two component and it very hard to clean tile if excesses not removed immediately) and having same issue like you - grout in wetroom area and a one line on tile outside is dark/wet and all dries after few days. I do not think this is acceptable and may cause more issue in long term. My tiles are laid on 18mm plywood and tanking has been done (painting with blue paste), but no wet foam tray has been used below tiles-tiler did nice fall with tile adhesive. Water doesn't get below floor so tanking luckily works. I was hoping to hear that epoxy solved the problem, but not long term ... what about using flexi grey Silicon instead of grout, would that work or this is silly idea?
I've seen other wetroom and all seem to be dry and nobody has any issue apart of you and now me 😉
Thank you for your thread.

 

[Rob-Bob]

btw, I was doing same investigation as you and the only way water can get behind the tiles are through a) grout or b) holes for glass screen frame (but this is unlikely as frame has been siliconed around unless water is going on the glass and fall between glass and metal frame on the wall, but glass sits on clear seal so unlikely).

 

[Paula]

Hi Paula,
I've just done wetroom and used porcelanosa 'swimming pool' grout (the one which you mix two component and it very hard to clean tile if excesses not removed immediately) and having same issue like you - grout in wetroom area and a one line on tile outside is dark/wet and all dries after few days. I do not think this is acceptable and may cause more issue in long term. My tiles are laid on 18mm plywood and tanking has been done (painting with blue paste), but no wet foam tray has been used below tiles-tiler did nice fall with tile adhesive. Water doesn't get below floor so tanking luckily works. I was hoping to hear that epoxy solved the problem, but not long term ... what about using flexi grey Silicon instead of grout, would that work or this is silly idea?
I've seen other wetroom and all seem to be dry and nobody has any issue apart of you and now me 😉
Thank you for your thread.

Hi Rob
sorry to hear you're having the same problems as me. I'm a bit confused, though: from what you say, it sounds like the Porcelanosa grout you used is an epoxy grout, which shouldn't change colour on wetting as far as I know. It is completely waterproof, so any water would just run off the surface rather than soak in, as is the case with normal grout. If the dark colour disappears on drying, then I don't think the epoxy is working properly, or you have another sort of grout maybe?

I know my thread is long and convoluted, but if you look back through it you'll see that we solved the original wetting problem by taking up the drain surround. It turned out that the tiler had not put enough adhesive under the metal drain cover, so water was able to get through the grout and pool under there. Perhaps you could you have the same problem?

I know some drains have seep holes built in, so that water that gets through grout and under tiles can seep into the drain rather than pooling. It could also be that these have been blocked by adhesive by the tiler. It may well be worth investigating.

If neither of these are problems in your case, then the water must be getting under the tiles through small cracks in the grout or around the drain. Are you sure there aren't any tiny cracks?

I've also wondered about using sealant, which would certainly be flexible enough to eliminate cracking, but I don't think it would look very nice, and am not sure how long it would last in such a wet environment.

You don't say whether your wetroom is on a solid or suspended timber floor. If it's on a solid base I would definitely recommend using proper epoxy grout, as it would not change colour at all on wetting (although I'd recommend eliminating the two possible drainage problems I mentioned first, as it's not good to have pools of water under tiles).

If your wetroom is on a suspended timber floor, then I'd steer clear of epoxy, given my experience, as it obviously can't cope with the movements that occur when someone is showering.

Hope this helps!

 

[Tilerdurden]

Possibly done the grouting in 2 applications and made a weaker mix which could cause variations in colour due to drawing out pigments and also weakens the grout strength. Could have dried at different rates. May possibly have cleaned grout too soon and water has hit it and discoloured and weakened the finish.

Reapplication of grout is most likely your best route of action. Should really be done at tilers expense.

 

[Rob-Bob]

Hello all,
Apologise for being quiet for 4 months, but I was undertaking a lot of trials with wet room.
1. pouring water into basket - floor still wet after a week so potential issue with piping or shower faucet
2. not using shower for a week - floor still wet so potential issue with piping or shower faucet
3. put Silicon over grout in wet room - wet room dry, but grout outside wet room became wet so potential issue with piping or shower faucet
4. decided to open shower plate and reconnect all fixture - floor still wet so potential issue with piping or shower faucet
5. spotted couple water drops from shower valve, about 1 drop per minute - change valve cartridge for £25, but this didn't fix the issue, when I turn valve water drops were coming out.
6. decided to replace whole shower mixer unit, went for Vado due to design and 10 years guarantee - knock some bricks behind the bathroom, plumber to deinstall old and install a new mixer, then plaster, skimming and painting.
7. removed Silicon which I put over grout
8. removed epoxy grout from wet room floor - extremely hard/almost impossible. Luckily Silicon soften the grout and I managed to remove about 6 inches of slightly cracked grout.
9. 6 weeks on and voilà - floor outside wet room dried and there is no sign of any water penetration in wet room.
I hope it will stay like this forever now and epoxy won't crack after while (it didn't cracked at all at other side of wet room from time of wet room build so it should be fine)
Couple things to note:
1. tanking is a must - tanking paint became a layer of plastic foil which really stops water penetrating floor or wall
2. buy good shower mixer and do pressure test after installation when all pipes are still visible and easy to fix
3. epoxy grout - I've heard it's not for wood subfloor, but Porcelanosa advised me to buy that type of grout for my wood floor. Epoxy grout is really a pain to apply, but it seems to work. I am still curious why grout was wet when water was underneath the tiles, but since new mixer was installed then grout is dry and stop water going behind tiles?
Thank you, hope someone would find this helpful 🙂

 

[Rob-Bob]

one more thing - it should one more point between 8 and 9 - apply epoxy grout into the places where old one was removed.