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

[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!