Grout issues in new bathroom

mgedidOctober 7, 2012

This community has been amazing for questions I've had in other parts of the house: please, please go to town on the latest.

We have had a new bathroom finished for several months, and our contractor, who is a family friend/business associate, said that he would come back and fix anything that we did not like, after we had lived with it for a while. Now I am seeing holes (well bigger than pinholes) in the grout on the walls and cracked grout where he built us a tile shelf. That's just the walls. The floor is worse. A bunch of the grout has come loose, and I have hollow spots where I can see through, possibly to the pan beneath? I think I can feel the tile squishing/moving beneath my feet as well.

So here are the questions: Do I ask this guy who clearly made a couple of mistakes somewhere to come back and finish the work? Can this be regrouted and fixed if it's this bad? These are the noises that this fellow has been making. However, it looks to this inexperienced eye like a total redo may be needed on the floor.

I know that sight unseen, it's hard to know what to advise. But what are the questions I should ask to get this guy to do the right thing, or to better evaluate the next person who comes to fix it?

Many thanks,


ps -- the time allows in the next couple, I will send a picture of the floor.

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The "squishy floor" is the danger sign.

Do you know the method of construction, from subfloor through tile and grout?

Is it a ceramic tile, or a natural stone? I've seen some low-grade "slates" that get saturated with water between the layers of stone, they can give a bit under foot and give a definite "squish" when stepped upon.

Pinholes in the grout can happen, but that normally shows up right after grouting. Entrained air bubbles that pop, for example.

The cracked grout at the shelf, that's probably differential movement.

Chunks of grout missing on the floor? That's bad. Is the grout just disappearing/dissolving, or are pieces actually breaking loose?

When it was built, do you remember if the thinset and grout used were a dry powder that was mixed with water? Or was it a pre-mixed "thinset" and "grout" that came in a resealable plastic tub?

    Bookmark   October 8, 2012 at 8:55PM
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The tile is ceramic, and as I think back, I have seen grout pieces falling out of the floor for some months, yes.

The grout was mixed from a dry powder, not a tub.

Question is, can grout holes like the pinholes in the wall or the cracks in the shelf or the floor be filled? It seems sort of delusional to imagine that they be repaired without redoing the entire setting process. I see more pinholes in the wall every time I look (they have probably been there, but I just wasn't aware of them) The grout that remains on the floor never seems to dry out. Not sure if there are multiple layers of grout already in place down there? I have no clue what is underneath the tile but will try to find out.

thanks so much

    Bookmark   October 8, 2012 at 10:34PM
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I didn't see you're reply until today.

Movement in floor is a bad sign. I'll never even attempt a repair on a shower floor with movement. It's best to do a full demo and rebuild the floor.

If your floor grout remains wet, it's usually a sign that the floor membrane was placed flat on the subfloor instead of being put on a sloped surface.

If the membrane was placed flat, then there's also a good chance that the installer packed mud too tightly in and around the drain's secondary weep holes and the weep holes are clogged.

With membrane on the flat, the non-sloped membrane won't direct water that gets into the mud bed towards the drain. If it did make it to the drain, it can't escape due to the clogged weepholes.

Your deck mud base is essentially saturated. Like a sponge. That's when you can get movement in the floor. A fully saturated bed can sometimes be lifted by a film of trapped water. That's where you can get the squishing sound, and the slight movement underfoot. Movement causes the floor grout to pop out. Missing floor grout allows more moisture into the deck mud. A circle of destruction.

It's a no-win situation.

Pinholes in the wall grout can be refilled. It's usually best to regrout sooner rather than later. Any repairs done at this time, it can be tough to get a color match so you'll probably end up with differential coloring in the wall grout.

To demo the floor, removal and replacing the floor membrane usually requires removal of the lower wall tile and tile backer board, up about 10" to 12" off the floor. That's because the floor membrane laps up the wall 8" to 10" behind the tile backer board.

A word of shower is not terribly old, but saturated mud beds can be horrifically disgusting. And that's coming from a guy that's seen some pretty bad things over the years.

It's sad to hear of situations like yours.

    Bookmark   October 11, 2012 at 2:26PM
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If he's really a family friend/business associate, I'd talk to him candidly (Maybe even without stress since you don't need any more of that) and say, "You know, stuff happen, etc. and I've got a mess to deal with...." Take it easy and go from there. May seem counter-intuitive but the damage is done. At least you know it.

Sounds like a tear-out and I'm wondering if he used the pre-mixed thinset. Guys, can that crud be scraped out if the pan is ok?....on the other hand, if somebody uses that stuff, they probably didn't do the pan properly with pre-slope, etc. to begin with.

Anyway, it's a mess, but life is short. Don't age prematurely over this mess. Live and learn.

(This is how a guy thinks on Sat. night with a good bottle of wine.)

    Bookmark   October 13, 2012 at 8:23PM
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As an update, my husband forwarded mongoct's response to our contractor via email, and he called immediately and said that he is coming to fix it. So a huge THANK YOU to you both for making these suggestions.

I now see that the mold growing up the wall grout (It seemed awfully soon for so much mold! Ick) could be related.

However, my ignorance about this kind of operation is complete, and I can't be put in the position of not knowing what is happening again. We need a subfloor over the pan? We need to be certain that the pan (or liner?) isn't damaged by the tearout? Could any of the floor or wall tile be salvagable? I know that I don't have enough floor tile to replace it all, so need to get on the ordering or this will never get done if so.

Gentlemen, again, this has been a lifesaver! Thank you.

    Bookmark   October 13, 2012 at 9:23PM
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It's difficult to advise you on how to proceed with repairs when I don't know the methods used in the existing failed construction. Regardless, grab a cup...okay, maybe a pot...of coffee. Here we go:

If he did a conventional CPE or CPVC sheet membraned shower, this link to Harry Dunbar's site shows how it should be built.

Things to note in Harry's pictorial:

1) A sloped deck mud bed (the "preslope") was placed UNDER the membrane. This now causes the membrane to slope to the drain. Any moisture that does get under the tile and into the upper mud bed will eventually get to the sloped membrane. Due to the slope it will flow to the drain and go through the secondary weep holes in the drain and then go down the drain.

2) Note his details about using tile spacers around the weep holes in the drain. A small handful of pea stone could be used too. Regardless of what is used, the voids created by the spacers help residual water easily flow through the weep holes.

Weep holes can be difficult to understand. Different drains have different methods. But the goal is to not seal them up. Do not pack deck mud tightly against them or in them.

I'll show a couple of clamping drains:

In the photo above, the weep holes are the ring of small holes that surround the threaded part of this drain.

In the photo below, there are weep holes like above, plus you can see the channel in the edge as well:

There's sometimes a little weep hole drainage gap or slot inside the recess for the bolt as well.

In this next series (also from Harry's site), note how the membrane was cut at the drain. The membrane gets clamped between the two halves of the drain, thus the name of the drain: a two-part clamping drain.

In the photo below, it looks all nice and neat in terms of how cleanly the bolts come through the membrane, doesn't it? Such wonderfully meticulous and clean work!

The problem is the membrane is so tight to the threaded bolts that the membrane itself will seal the weep holes closed when the drain is clamped. With the upper part of the drain now bolted on, you can't see the weep holes. And neither can water:

In the previous example, the "nice and neat work" resulted in the membrane actually sealing the weep holes closed. Water that gets into the mud bed will be held there, resulting in a saturated bed that can grow some absolutely awful stuff. Creature From the Black Lagoon stuff. Even if this is what happened with your shower, your shower isn't terribly old, so you may be better off regarding the funky stuff.

In the next photo you can see the membrane is cut in a "U" shape around the bolts, exposing the weep holes next to the bolts. The holes are tough to see:

Now when the clamping ring gets installed, the weep holes are open. It's tough to see in those photos, but you can see a dark spot (weep hole) in the bolt recess:

Here's an example of clogged weep holes. Mud packed into each and every crevice of the drain:

Again, I don't know how your shower was built. So the preceding could be a part of your problem. Or it may not be. But it's a bit of a primer on why the membrane needs to be sloped, clamping drains, and weep holes.

"I now see that the mold growing up the wall grout (It seemed awfully soon for so much mold! Ick) could be related."

That's usually a sign of a saturated mud bed, and that your tile guy buried the bottom edge of the cement board in the mud bed, or "pinched" the cement board between the mud bed and the wall studs. The bed is saturated. Because the bottom edge of the cement board is buried in the deck mud, water can wick up the cement board on the walls via capillary action, saturating the grout from behind. The high moisture level in the mud bed results in perpetually moist grout on the lower part of the walls.

"We need to be certain that the pan (or liner?) isn't damaged by the tearout?"

I hate to say this, but I never advise reusing a salvaged membrane. The membrane is your last resort in terms of protecting your house's structure from water damage. During demo there will be...demo...going on. Violent demolition. Or gentle demolition. It's still demolition. Even though a salvaged membrane may look fine? Replace it. That's my advice. You simply have to chalk it up as a cost of failed construction.

"Could any of the floor or wall tile be salvagable?"

It could. You may need to grind any thinset off the back of the tile so it can be cleanly reset. Any cured thinset globs or blobs or smears will essentially create a tile with uneven thickness. That could result in lippage issues when reused. So it's an "it depends" answer. They could be reused. But there could be issues with reusing them.

Now one last thing: there are ways to repair clogged weep holes. But your floor is "squishy", and a squishy floor means movement. That's usually the death knell for a shower floor in terms of a repair versus a replacement. Movement usually means replacement.

Best, Mongo

    Bookmark   October 14, 2012 at 10:39AM
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Back to materials used.

In my first post I asked if the thinset and grout used were mixed from a dry powder or if they were an already mixed product that came in a resealable plastic tub. The premixed products are referred to as "mastics".

You answered that the GROUT used was mixed from a dry powder, but never commented on the thinset that was used to set the tile.

Ask him specifically about that. If the material used to set the tiles was a premixed product, those materials are actually water soluble.

So it could be that the premixed tile adhesive (mastic) has re-emulsified and softened and is no longer supporting the tiles. It's only the tiles that are moving, and not the entire mud bed.

That in and of itself could possibly be a good thing. Maybe not a good thing, but "less worse".

But it also signifies that the bed itself is holding water. Enough water at least that the held water is wetting the mastic enough to cause it to re-emulsify.

So again it comes down to why is the mud bed wet?

Is it because the membrane was placed flat on the subfloor instead of being placed on a "presloped" mud bed?

Or is it because the secondary weep holes in the drain are clogged?


So here's my "sort of" ray of sunshine:

If the membrane is indeed sloped. And if the weep holes are simply clogged. And if he used mastic instead of thinset, and the softened mastic is causing the tile movement and the squishy sound underfoot, then you could possibly just repair the weep holes.

1) Remove all of the shower floor tiles, scrap any residual mastic off the mud be surface. Clean the removed tiles as well.
2) In about a 12"-18" diameter area around the drain, dig out the mud bed to expose the drain base and the weep holes.
3) Clean out the weep holes.
4) Leave it open to free air until the mud bed dries. If it's truly saturated, you might even get a little water pooling in the dug out area.
5) Use tile spacers or small stone to preserve the weep holes, then repack new deck mud.
6) Reset tiles with dry powder thinset, and grout with dry powder grout.

1 Like    Bookmark   October 14, 2012 at 1:55PM
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Wow. Mongo, I hope you know the value of the service you're providing here. I don't know what to say except a huge THANK YOU. This is immensely helpful.

One final question: We have a tiled step that divides our shower door [frameless] from the rest of the bathroom. We have also had issues with the grout outside the shower looking wet and a darker color than the inside since we started to use it. I now realize it is likely wet grout over a foot away from the shower door. There is no movement under these floor tiles -- It just looks like the water wicked over there via the grout. Do I have to worry about ripping this out as well, by the same theory that has us ripping out the walls up 12"?

    Bookmark   October 19, 2012 at 3:40PM
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You are welcome. I appreciate the positive feedback.

For clarification:

You have a slower floor, which is sloped upwards from the drain to the curb. At the curb it goes up vertically for a few inches. Then horizontally cross the curb. Then back down to the bathroom floor (outside the shower). Then the bathroom floor runs horizontally away from the shower.

It's this area outside the shower, on the bathroom side of the curb, that you are seeing a perpetually wet floor on terms of wet grout?

I don't know how your shower was constructed. But nothing you describe makes it sound like it was built correctly.

It's so difficult to give any construction advise without me putting eyes on the project. That's not a solicitation. That's simply fact.

Try to get from your guy information on how he built your shower. Compare it to Harry's methods, step-by-step. Down to fastener location. Pay attention to the fact that no fasteners are put through the membrane on the shower side of the curb.

    Bookmark   October 20, 2012 at 1:11AM
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