Shower leaks & re-grouting advice please

[dr_gn]

All,

Our house was a “self-build” (by me) in 2004. I installed three tiled showers and they have been completely trouble free until recently, when we noticed staining/drips under two of them. I’ve established it’s not the drains; when I tape a plastic sheet over the walls, the leak stops. I put a ceiling access panel under the main one, so I can see directly the drain pipework on that one is dry.

I re-grouted the main shower twice in a matter of months, but the leak persists. Before doing it again - and the other leaking shower, I’d like advice on grout. I did use conventional stuff (which has clearly failed) and was wondering if epoxy grout would finally cure it?

I’m using a multi tool to remove the old grout, and am using silicone sealant around the wall/base joints.

I’ve heard from a few people that once a shower starts leaking, it leaks forever! So any general advice on grout brands, application and clean-up would be much appreciated.

Thanks.

[OutInTheShed]

First thing is to look closely and see if the grout is properly bonding to the tile edges.

Normal bathroom grout is not 100% waterproof, but the amount of water which should come through during a normal shower is tiny, going on microscopic.

You can try a 'grout sealer' but I would not have high hopes for that if the grout is cracking away from the tilde edges.

Also, check the faces of the tiles, has the glaze crazed?
A clear sealer may work on this too.

Last shower I had to re-grout, I used Dunlop grout with the additive which makes it good for swimming pools.

[Actual]

I am doing our bathroom. I removed the old tiles and plasterboard and reboarded with waterproof Abacus Elements foam backer board with all joins sealed. Then using Aqua Strap which has a heavy duty adhesive to seal the backer board to the shower tray. I am then using Abacus shower panels bonded to the backer board and overlapping the shower tray and siliconed around the tray. This should be double waterproof.

[dr_gn]

So I’ve ripped all the grout out of the lower sections of the shower, and the silicone sealer around the bottom. The lower tiles were a bit loose, so I managed to remove them without damage, and have cleaned most of the old adhesive off the back. The full sized upper tiles seem solid and I doubt I could remove them without significant damage.

Questions:

1) Should I somehow seal all the exposed old plaster board, the back of the tiles and the grout lines before re-fitting?

2) Should I grout to the fibreglass tray, or use only silicone along those edges to give some flexibility?

Also decided to try epoxy grout this time - if that makes any difference to the sealing advice?

Thanks.

[OutInTheShed]

Probably worth priming/sizing the plasterboard with some kind of water-based. waterproof sealer.
The tile adhesive instructions may tell you...

Definitely flexible sealer of some sort between tiles and tray.

[Actual]

I've had rotten tiles at a previous property. The tile grout allowed water though and the plasterboard behind was rotten. Any fix was temporary as it didn't matter how much silicone and sealing was used the water always got though.

I think that your fix will work for a time but will fail again.

We paid £K for a new bathroom using shower wall panels and not tiles but the installer didn't reinforce behind the shower wall panel and so there was flex at the shower tray and even that new bathroom didn't last.

At our recently purchased house I'm working on my shower tray installation now. The shower walls are made up with waterproof Abacus tile backer board and all joints will be over tapped and sealed and there will be a Aqua Strap sealing strip around the shower tray which will be waterproof behind. The shower will be faced with shower wall panels which will be sealed to the tray and waterproof in front.

The idea is to have 2 layers with each layer totally waterproof but any compromise especially at the corners will render the whole lot useless.

My challenge tonight is that at the shower tray is bigger than the room so at the ends the backer board overhangs the shower tray so getting the sealing strip to work is difficult.

What could go wrong?

Edited by Actual on Friday 23 May 20:29

[OutInTheShed]

Actual said:

I've had rotten tiles at a previous property. The tile grout allowed water though and the plasterboard behind was rotten. Any fix was temporary as it didn't matter how much silicone and sealing was used the water always got though.

I think that your fix will work for a time but will fail again.

We paid £K for a new bathroom using shower wall panels and not tiles but the installer didn't reinforce behind the shower wall panel and so there was flex at the shower tray and even that new bathroom didn't last.

At our recently purchased house I'm working on my shower tray installation now. The shower walls are made up with waterproof Abacus tile backer board and all joints will be over tapped and sealed and there will be a Aqua Strap sealing strip around the shower tray which will be waterproof behind. The shower will be faced with shower wall panels which will be sealed to the tray and waterproof in front.

The idea is to have 2 layers with each layer totally waterproof but any compromise especially at the corners will render the whole lot useless.

My challenge tonight is that at the shower tray is bigger than the room so at the ends the backer board overhangs the shower tray so getting the sealing strip to work is difficult.

What could go wrong?

Edited by Actual on Friday 23 May 20:29

If you attempt to have two waterproof layers, the usual outcome is water trapped between them!

Very few things are 100% impermeable to water.

[dr_gn]

Thanks guys. Yes, it seems it may need completely re-doing at some point, but if I can get it "OK" for a few years I'll be happy.

I can't beleive I got it right 20 years ago - on three separate showers - having never fitted a shower of done tiling before. I didn't do anything particularly elaborate at the time.

The plasterboard looks damp in the images, but it's actually bone dry and pretty solid considering some of the coating was removed with the adhesive on the tiles. The shower hasn't been used for about 4 months, and before that I'd put plastic sheet over the lower areas to try and narrow down the leak as outlined in the o/p.

[Vanden Saab]

You have two problems. First you have water running down from higher up and secondly both the bottom and end silicone joints have failed.
Personally I would regrout up to shoulder height. First run a thick clear silicone bead along the Base and corner before regluing the bottom tiles into it before it cures. Then regrout the whole shower and apply the final silicone as usual.

Edit. Epoxy grout will not help you. You are far more likely to have problems with it than standard grout. Epoxy will not allow moisture to come out from the wall so in effect will leave it with no option than to soak through the wall.

Edited by Vanden Saab on Saturday 24th May 20:10

[dr_gn]

Vanden Saab said:

You have two problems. First you have water running down from higher up and secondly both the bottom and end silicone joints have failed.
Personally I would regrout up to shoulder height. First run a thick clear silicone bead along the Base and corner before regluing the bottom tiles into it before it cures. Then regrout the whole shower and apply the final silicone as usual.

Edit. Epoxy grout will not help you. You are far more likely to have problems with it than standard grout. Epoxy will not allow moisture to come out from the wall so in effect will leave it with no option than to soak through the wall.

Edited by Vanden Saab on Saturday 24th May 20:10

Thanks. The strange thing is I’ve re-grouted and re-sealed once, then again (partially around the base), and this had no effect on the leak. I thought it might be the pipework behind, but apparently not.

I could re-grout to shoulder height easily (to where my hand is) apart from the small glass band, which would be a nightmare to get the old grout out:




I wasn’t able to remove the very end tiles without removing the entire shower frame:





The corner isn’t in great shape:



Plan is to scrape out any loose adhesive from between the tray and plasterboard, and the corner, then seal the old board and cleaned-up tiles.

Not sure what you mean about setting the tiles on silicone? Intention was to re-set the tiles on a continuous bed of new adhesive, then re-grout and re-silicone around the base. Are you suggesting I simultaneously use adhesive on the back of the tiles, and silicone at the base?

I wonder if I should grout the vertical corner, or just use silicone?

Any advice on process gratefully received.

[OutInTheShed]

The grouting around the glass mosaic tiles looks dodgy.
That's a classic change of tile thickness which creates a little shelf where water sits and soaks into any weak point in the grout.

[Belle427]

If the plasterboard is sound as you say id just clean up, re tile, grout and use a decent sealant along the bottom and also the corner.
Take care using sealers, stuff like pva is not good for jobs like this and failures are experienced later down the line when water gets in.

[Vanden Saab]

OutInTheShed said:

The grouting around the glass mosaic tiles looks dodgy.
That's a classic change of tile thickness which creates a little shelf where water sits and soaks into any weak point in the grout.

Ah you saw that too. The black shows exactly where the water is getting in...

With my comment. I am suggesting that you clean out the area between the wall and the tray and when you are ready to retile you first silicone the bottom and corner before you set the tiles so that the area is sealed before you grout and silicone on the outside. It might give you a year or two before it leaks again but rebuilding is the only real solution.
Recently did a refurb that looked perfect from the outside but once we took the tiles off we found this...



If you look at the first pic you can see the little black dots on the grout lines by the corner silicone joint. That was where the water was getting in. We had to rebuild both walls as they were rotten.

[dr_gn]

Thanks all. The black on the mosaic is mould on the surface of the grout. The grout itself is sound - or at least is no different to the grout anywhere else along it.

I don’t understand why you’d need to remove and re-tile the entire shower? The tiles themselves can’t let water through, so that leaves the grout. If the grout is removed and replaced with new, how is that different from putting grout in new tiles? Surely you have the same chance of having errors/leaks?

Also, is there a coating you can paint onto the grout that repels water?

Thanks.

[GasEngineer]

this stuff is very good. makes a waterproof skin.

https://www.ct1.com/products/bw1/

[Djtemeka]

99% of the time it leaks where the shower enclosure meets the wall at the bottom.
Most people replace the silicone with the enclosure in situ.

Sometimes there is no silicone behind the wall rail. Other times it’s failed there but you can’t see it.

100% every time you reseal a bath tub or enclosure you need to remove the screen or enclosure.
Clean and reseal the tray or tub.
Wait 24 hr minimum then return and refit the enclosure/screen.

As you have plasterboard, it’s fked. Full
Strip out or nothing at all.

[-Ad-]

Plasterboard in wet areas really is "pants on head stupid". Even ply is recommended against in the British Standard (no idea the number of it).

Had a youngish tiler say he would use ply for everything and these cement boards with waterproofing systems were all a snake oil con, then quoted £250 day rate and 4 days to tile a small 2.4x2m floor area.

Just doing 3 bathroom refurbs myself currently and have all the cement boards and waterproofing kit going on. Belt and braces, do it once, do it right.

[dr_gn]

All I can say re. tiles on plasterboard is that the three showers I fitted in the house in 2004 have been leak free until now. And two of them have had daily use from a family of four.

I guess I’ll remove the enclosure and the remaining corner tiles and fully re-seal the tray-wall.

[Vanden Saab]

dr_gn said:

All I can say re. tiles on plasterboard is that the three showers I fitted in the house in 2004 have been leak free until now. And two of them have had daily use from a family of four.

I guess I’ll remove the enclosure and the remaining corner tiles and fully re-seal the tray-wall.

And now the grout and or silicone has failed and the plasterboard behind it is compromised. Imagine leaving a cardboard box out in the rain.
I can tell you what you need to do based on doing it for the last 35 years but it is your bathroom so crack on. I give it six months before it starts leaking again.

[Pheo]

Basically things have moved on alot since 2004! Also if you've not used it for 4 months likely this is why the PB is dry.

95% certain it'll be movement between tray and wall, mastic has failed and then water gets in. Even had this is a recently done shower with micro cement. I fitted a rock-it seal and seems to be OK now. Sadly don't think the tray was fitted well by the plumbers and too much movement, so it may fail again - but trying to avoid ripping it all out as it's only 2 years old. I did tank it, but obviously any movement in the floor will pull that away, But I think it saved the plasterboard from the leak underneath.

If you want to bodge it you reseal with silicone, and as you say you may get away with it for a year or two, maybe more, but you risk doing it over.

I would personally fit an upstand under the tiles, and then reapply them, and redo the grouting, and seal it, as a halfway house.