Ahhh!!! Please help... [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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06-27-2019, 06:18 AM
Hi guys DIYer, have tiled a couple times but never used Kerdi board before this project. I always appreciate your guys’ help. Just finished installing the Kerdi board for my tub surround. The drywall sticks out further than the KB where the two meet. Part of this is due to the KB being slightly thinner than the drywall. It’s much worse in spots, though, where the drywall was uneven (butt joint), and where KB is screwed in. In order to get an even tiling surface I know I’ll have to build out the thinset and Kerdi band the transition.

My question is - does it matter which side of the Kerdi band the excess thinset ends up on? If there’s excess thinset between Kerdi board and Kerdi band, does this affect how waterproof it is? I could see how the water would be able to soak through the thinset to the surface beneath, but maybe I’m worrying too much? To me it seems building out some underneath, then applying the band on top would be easiest but I thought I better get your guys’ expert advice. Thanks!

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06-27-2019, 07:34 AM
Welcome, Jordan. :)

No, KerdiBand doesn't care which side is on which surface.

Yes, an excess build-up of thinset mortar under the KerdiBand will cause the joint to be less water resistant.

But, your joint to drywall should not be in the wet area of your construction at all, so it shouldn't matter much. If the joint is in a wet area, you really should move it.

My opinion; worth price charged.

06-27-2019, 12:31 PM
Perfect. That’s what I was thinking. The one area of transition that might be subject to a little more water exposure is at the top of the tub opposite the shower head, where the tub and kerdi board seam meets the drywall. I’ll be a little more careful in that area and thanks to you, CX, will be that much more confident in the install. Thanks again!

07-09-2019, 06:38 AM
So I screwed up. Big time. I've been scrambling the last two weeks trying to finish tiling my tub surround so I can have a shower again. I'm just a DIYer and obviously uninformed. I Did 13" porcelain tiles over kerdi board using TEC Uncoupling thin set (which apparently was expired...), then finished last few tiles with new bag of Mapei Uncoupling.

I just laid the last tile last night and started cleaning out the grout joints on the stuff that was already installed prior and noticed how much harder the Mapei was, even though it hadn't cured near as long. Got on the internet only to learn (unbeknownst to me) thin set expires. The TEC has been in my basement for two years. It's air conditioned down there and we live in a low-humidity area so I'm hoping it's salvageable.

I'm wondering if I keep as much moisture off the thin set as possible if it will help the job last. If I were to add some 511 sealer to the thin set in the grout joints BEFORE adding the grout to try and seal them up, then grout, then seal the grout would this help? Is all lost? Thanks to all of you experts out there who reply.

07-09-2019, 07:27 AM
we live in a low-humidity area Comments such as that are a good deal more meaningful if you'll add a geographic location to your User Profile, Jordan.

I would expect your plan for the use of a "sealer" such as Miracle 511 in the manner you suggest would be more likely to cause further problems rather than solve any.

Your only real option if your out-of-date mortar won't properly cure is to remove the tiles, clean off the mortar, and re-set them using a suitable mortar.

My opinion; worth price charged.

Fast eddie part deux
07-09-2019, 10:30 AM
The good news is ... if the old mortar doesnt set up it will be easy to remove.

07-09-2019, 11:42 AM
Keeping a cement based mortar or grout damp, not soaking (assuming it was mixed properly) can actually make it reach its maximum strength. In reality, though, unless something removes the moisture before the cure can take place, mixing it properly should provide all of the moisture needed. Any moisture that is not chemically combined with the cement to cure it will eventually evaporate. The moisture used in the cure becomes part of the cement.

07-10-2019, 06:10 AM
I did try and yank a 4x13” tile off by hand and it didn’t budge. It was on the border so I was able to get a pretty good grip on it. I’m still a bit leery of what could happen when the shower starts being used...

But, with the amount of time I’ve put in and how close I am to being done I think I’m going to put the best grout on I can and roll the dice. I figure the worst that can happen is I have to replace each tile once (now or later), but it’s possible they will all stay.

I bought some TEC Power Grout ($89 per 25 lbs?!) last night because a reputable tile store said that’s what their installers used and loved. but after reading tons of horror stories online I am going to return it for something more DIY friendly and with fewer issues.

I think this store keeps Mapei grouts on hand, which from what I’ve read on here sound decent. Any input on a high quality, well-sealed grout system, Mapei or otherwise?

I started this project over two weeks ago and am definitely ready to be done tiling (not to mention ready to start using this shower instead of taking baths upstairs), but if I have to special order some grout to help me sleep better at night I will. :loaded:

07-10-2019, 01:05 PM
I as a DIY'er try to stay with the same manufacture, thinset and grout. My thinking that the manufacture considers their products and tries to enhance them to work together. Plus if you need to call Cust. Service for tech help. They have a good understanding on their products and can not blame another manufacture for a problem area.