Crack in grout at change of plane

[khipsher]

Hello,

We have a newly built home that was completed 8/2021. The builder’s crew did the work in the master bathroom, including the shower. They are two guys with decades of experience, but not exclusively doing tiling. They were conscientious and did an excellent job on the many parts of the house they worked on, but I am disappointed that they grouted all the change of planes in the shower, as I thought best practice was to use silicone caulk for that (completely open to advice if I am wrong on that).

I had purchased Mapei Mapesil T silicone caulk and included it with the tile and grout materials. When I saw the grout at the change of planes instead of the silicone and asked them about it, the lead guy said, “Oh, we let the owners take care of that.”

The grout has cracked at the base where the walls meet the floor. Tile is travertine. Grout is Mapei Ultracolor Plus Rapid Setting.

What should be done now – all the grout in the change of planes be removed and replaced with the silicone? Remove some of the grout but not all and replace with silicone? Silicone right over the grout?

If you can provide information about correct steps, how-to’s and any pitfalls to avoid, we’d be really grateful.

Thank you!

[cx]

Welcome back, Kathy.

You need to contact your builder again and throw the Bullshit card on the advice that "we let the owners take care of that."

The reason for the flexible sealant in the tile joints at the changes of plane is to provide movement accommodation. There is absolutely no value in putting any silicone sealant over a joint that has already been, quite incorrectly, grouted.

The installation of both grout and flexible sealant is part of the tile installation and is the responsibility of the tile installer.

At this point, the only remedy is to remove the grout in those joints and install the flexible sealant as should have been done initially.

One potential problem with doing that depends upon how the walls and floor of the shower were waterproofed. Do you know how that was done? Have any photos, perhaps, of the work on the shower in progress?

My opinion; worth price charged.

[jadnashua]

There's a reason why the industry guidelines call for movement accommodation for changes of plane...your pictures are good indication of why they are the standard...

[Tool Guy - Kg]

Originally Posted by cx

You need to contact your builder again and throw the Bullshit card on the advice that "we let the owners take care of that."

I was thinking on how to say just this when I read CX’s post. Can’t phrase it better than that.

[khipsher]

Thanks, everyone. I really do appreciate you taking the time to weigh in.

CX, this is the only picture I have from before the tile was finished. I'm sorry I don't have more. Also, I wasn't able to get the picture attachment to orient vertically.

Is it enough to tell you anything helpful about next steps?

[makethatkerdistick]

I don't see any waterproofing between backerboard and tile. Still quite possible that there is a waterproof layer of something behind the backerboard, but it is impossible to tell. The fact that I see an untaped backer board joint makes me wonder whether they taped and mudded that before they tiled over it. If I had to guess, I'd say they probably didn't, but impossible to say without further information.

Most backer boards are not waterproof per se, only water resistant (such as cement boards). Do you know what material the backer board is?

You might want to ask your builder about the manner in which the walls and the shower floor were made waterproof.

[cx]

I would echo what Wolfgang said, including the part about needing more information. Whatever you can get would be helpful.

Perhaps your tile man also thinks the waterproofing and treatment of the wallboard joints should be left to the customer, like the flexible sealant in the changes of plane?

[Tool Guy - Kg]

I think your tile guy also thought it was your job to remove the smears of grout, as well. It’s kind of impressive how much grout is still on that tile surface instead of being cleaned off. That’s now rock hard and will prove to be very difficult to remove.

I also sure hope that the fasteners for that bottom support cleat haven’t punctured the liner that might be behind that substrate.

Speaking of the substrate: if it’s Hardibacker board, the manufacturer prohibits it from being buried into the pan’s mud bed (as it appears to be).

[khipsher]

I will work on getting more information about the materials and installation methods and post that here when I have it. Thanks, everyone.

[khipsher]

I'm attaching an additional picture I found that shows the vinyl pan liner and Hardi backerboard that was used in our shower install. Unfortunately the Hardi was installed in the mud bed. There was no Redguard or waterproofing membrane installed above the shower pan, but the seams between Hardi boards were taped with mesh and mudded. Modified thinset was applied over the whole surface before the tile was applied.

In the previous picture I posted, what looks like an untaped seam between Hardi boards is actually a pencil line drawn on the thinset layer applied over the Hardi that marks where the shower band was planned.

Our builder has agreed to fix the crack in the grout with silicone in whatever manner we would like. So I am back to the original question of the correct manner to go about that. Many thanks for any advice on the correct steps for him to take.

[jadnashua]

The instructions for HardieBacker specifically say that the board MUST be terminated ABOVE the top of the mudbed, and NOT embedded IN it. So, this is a major problem long-term. From the data sheet on HardieBacker, it can contain up to 14% cellulose fibers, i.e., wood fiber. It does make the HardieBacker stiffer, but also, will swell if it gets saturated. Inside of a mudbed of a conventional shower pan, it WILL get damp. When cellulose gets wet, it expands. Since cellulose is also organic, it is subject to support mold growth.

IMHO, a so-called 'pro' should build a shower according to industry standards and that also includes following the instructions of any products they choose.

Now, had the board been a 'conventional' cement board, the procedure IS to embed it in the mud bed, but you can't do that with HardieBacker. The TCNA handbook, the industry bible, has a separate procedure when that type of board is used. They did not follow that. Grouting changes of plane is also against the industry standards, so what else did they mess up?

[Snets]

Kathy,

I downloaded your photos and rotated them. I cannot say 100% but what I see in the two photos:

1) No waterproofing on the shower walls, and no vapor barrier behind the CBU wall board - should be one or the other.

2) No pre-slope under the vinyl receptor liner in that last photo - The vinyl liner should be sloped toward the drain, then mortar bed on top, then tiles.

[cx]

Am I the only one who doesn't see a curb at the entry of that shower?

[ss3964spd]

No, Sir, not the only one.

The liner does look pretty flat in that last photo but I'd not swear to it from here. I'd be interested to see what the transition from the bathroom floor to the shower floor looks like now. If there is a curb I'd definitely want to know how it was built and water proofed.

[lochrie22]

I wonder if all the cracking along the floor that is seen in the first photos happened so quickly because the Hardi is embedded in the Mud Bed