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

[Paula]

We had a wet room installed about 8 months ago. The floor is tiled with large 60x60cm porcelain tiles laid on Impey Waterguard membrane and the shower tray is Impey Aquadec Easyfit with the membrane laid over the top. It is a new-build first floor bathroom (new extension on older house) with a suspended timber floor. The tiles appear to be laid well and there has been no obvious movement or cracking of grout (Bal Micromax). However, almost immediately we noticed that in the shower area some areas of grout (which is light grey) did not dry out, and over time about 50% of the grout lines were permanently dark, even when the shower was not used for a few days. I searched tiling forums and became concerned that the tiles had been laid on an incomplete layer of adhesive, and that water was pooling underneath them, leading to permanently wet grout, but could not see any evidence of the tiles coming up or moving about, which usually seems to happen with problems like this.

Our builder called back the tiler who swore that he had used the correct amount and type of adhesive, and said that if he had not done so then the grout would have cracked on the floor. Bal, the grout and adhesive manufacturers, were called, but their "expert" tried to claim that the dark patches were not, in fact, wet, but possibly mould or even dirt! He agreed that it looked like the tiles had been correctly laid and suggested leaving the floor to dry and then replacing the grout and then using a sealer to stop water soaking through the grout. When I mentioned the possibility of adhesive not covering the back of the tiles, he agreed with the builder that it was very difficult to achieve a completely flat bed of adhesive, suggesting that it was almost inevitable that some pooling of water under the tiles would occur, leading to patches of wet grout.

We agreed to wait for the floor to dry out. We are now on week 5 (in a warm room with underfloor heating in the rest of the floor away from the shower tray!) and there is still a small wet patch, but most is back to the normal light grey colour. It took about 3 weeks for most of the moisture to go and the dark patches to disappear, so we have now discounted the mould/dirt theories, but are concerned that there must have been quite a lot of water sitting under the tiles for them to remain wet so long! The builder now just wants to seal the dried grout, and not re-grout at all. He is refusing to do anything else.

I have talked to most of the manufacturers of grout sealers, and they all say that their products will not completely waterproof grout, so I cannot see that this will be a long-term solution (also, don't fancy waiting for the floor to dry out each time it needs re-applying!). Epoxy grout seems like a good idea, but the builder seems to think that it would eventually crack if used on a timber floor (although when I spoke to Mapei about Kerapoxy they said that it should be fine as long as the floor is not bouncing around a lot, which it is not).

What I'd really like advice on is:

- is it normal to have permanently wet patches in grout on wet room floors even if the floor appears to be well laid?

- if we leave the floor as it is, will we be storing up trouble for the future? Am I being too fussy??!

- Is it possible to lay tiles in a pre-formed shower tray on a completely flat bed of adhesive, or will there always be gaps for water to collect in?

- Should we consider a grout sealer or epoxy grout to solve the problem or do the tiles need taking up and re-laying? (massive Job I imagine as
there is a huge glass shower screen resting on one grout joint and the membrane may be damaged in the process?)

It does feel like I am being fobbed off by the builder and the tiler, but admittedly the wet grout patches are the only problems so far. It would be great to hear from anyone who has had similar problems. I can't quite see the point of having tiled shower trays if they always look different to the rest of the tiled floor!

Thanks!

 

[Paula]

Well, the tanking is meant to fall into the trap/drain. So the tiles then just become aesthetics to make it all look nice and easy to clean. They're not there stopping water getting anywhere sort of thing.

So it's usually okay for tiles to have cement-based grout, it get wet, water get behind the tiles and soak a bit into the cement-based adhesive, because the water that collects will fall into the drain, and the remaining water behind the tiles would disperse and dry out via the grout generally across the whole floor.

You'd get wet / darker grout using the shower, and a hour or so after, it'd dry out. Wouldn't stay patchy, but might be a bit patchy during drying out etc.

The epoxy has perhaps if anything stopped a bit of that and is pushing the moisture further into the bathroom maybe.

But the fact you're getting droplets of water and it's in quite a few grout lines, but then not others right next to it, would suggest as Deano's said, it's fresh water that's quickly gathering, and taking ages to dry out.

So I'm not sure what's going on around the drain. But it's okay for water to get there usually, as the drain would get rid of it (gravity) and the rest would disperse into the floor generally and evaporate once it's (evenly) reached the surface of the grout. But I've never seen droplets like the earlier images.

I don't think I've still answered you lol sorry. I just don't know what to say about it.

I'm with deano though, I'd have pulled a tile or two up around the drain by now.

JUST A THOUGHT.....


I'm loathe to do that as that will probably damage the membrane. From what you are saying, I just wonder whether the problem is arising with the shape of the shower tray? If you are now saying that it is normal for water to get under the tiles around the drain (I thought before everyone said that this shouldn't happen unless the adhesive was spread unevenly and there were lots of gaps?), but that is OK as gravity will cause it to fall into the drain down the slope, then maybe our slope is not steep enough?

That may have lead to more 'pooling' of water under the tiles than would normally be expected, and therefore it would take much longer for the water to evaporate through the grout, leading to permanent damp patches (which is what we had pre-epoxy). Now we have stopped evaporation through the epoxy, the water is just migrating to where there is normal grout, through which it can evaporate (this is how plants move water from their roots to their leaves, as evaporation takes place through pores in the leaves and leads to a difference in water potential from leaf to root, hence flow of water). So that's why we have damp patches beyond the shower tray.

How would I find out if anyone else has had this problem with an Impey tray? When I originally spoke to them, they said that I should not have any permanently wet patches and that it was a tiling problem!

 

[The D]

It is NOT ok to have water under the tiles it's a problem

 

[Dan]

If you have cement-based adhesive, and cement-based grout, and have tiled to a former, that runs into a trap, and you use a shower, you have water behind the tiles. As it's getting through the grout. That isn't water PROOF, just doesn't break down with water.

So it's going to fall into the trap.

Right?

Am I missing something?

 

[The D]

yes lots

 

[Dan]

Oh right.

Sort of renders tanking useless then if the tiles are the water barrier eh?

@Paula, listen to @deanotile, he's the tiler out of the two of us.

I don't want to tarnish the thread with a bad tone or anything so I'll stay out of it if I'm giving the wrong advice.

 

[The D]

tanking is a failsafe so that if there is a problem the water is contained and the background is not damaged the primary waterproofing is the tiling.

 

[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 silicone 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?