# Shower Corners



## angus242 (Oct 20, 2007)

You wanna start big pimpin from the beginning? Use Mapeband in your corners before waterproofing. Before I hung up the trowels, I was spec'ing GoBoard for panels, FibaFuse tape with AquaDefense on screws/seams/corners. Hydro Ban Sealant for joints you can't get with a membrane (walls to tub). At the time, Mapeband was hard to get. If I were to do one tomorrow, I get it. Your movement is absorbed and less chance of a transfer to your finished tile & grout. Plus, it's 100% waterproof. Always.


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## Seven-Delta-FortyOne (Mar 5, 2011)

There are so many products and systems out now that I’m having a hard time keeping up.

And I don’t do a ton of tile to begin with, a few projects a year.

I’m thinking about doing a Schluter class in April, but I don’t really have time.

AquaDefensce and Hydraban , are those liquid membrane products? Are they Laticrete brand?


I’ve been wanting to use a urethane grout on my next project. Do you have a favorite brand? I use Custom probably the most, followed by Mapei.

Have you ever considered writing a book? 😳👍🤣


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## angus242 (Oct 20, 2007)

I'm a Mapei fan. Nothing wrong with other manufacturers, it's more that I'm most familiar with their product lineup and I get the best prices from them.

AquaDefense is Mapei, HydroBan is Laticrete. Redgard is Custom. Those are the big 3. Use whatever you can get & within budget.

You can easily use cement board for the wall panels. It's tried & true though timely to install. If you use CBU, make sure to use the proper screws. Too many guys hang it with drywall screws. You need alkali resistant ones. You can paint the membrane over the CBU but the seams and corners will need extra help. That's when "they" recommend alkali resistant tape. I skipped that step because that stuff is really designed to be embedded within thinset. Instead, I use FibaFuse drywall fiberglass mesh tape. The FibaFuse mesh is much smaller than the other stuff so the liquid membrane holds very well. It creases easily for corners. I brush on some liquid, embed the tape and follow up with at least 2 more coats after the previous has cured. You can use air flow to help dry.

The liquids are also considered crack isolation so they have a much less chance failing in the corners due to change of plane movement. Yes, there are always newer, faster products but they usually come with a cost and availability problem. I like the waterproof panels but they are harder and harder to find stocked and the costs keep rising. I was lucky enough to have a drywall sub do my hanging for me so I didn't care what ended up on the walls. CBU took a bit more liquid but you still burn a full day waterproofing.

As for grout, Mapei FlexColor CQ is the best I've used. It has all the benefits to urethane but has a bit of an easier install. Both are *NOT* installed like cementitious grout and you need to be schooled on that _before_ you use it. Mapei has more support products too. They have a grout release that you use before grouting. And if you missed some spots when cleaning, their product to remove the haze is more readily available than Bostik's.

The pics I posted in the tile projects thread, I used the grout release because the tile is matte white glazed. I didn't want any chance of the haze drying & not coming off. It's a wipe on, set for a few hours and go about your business normally product. It puts a little protective layer on the tile surface that comes off when cleaning. The "fancy" grouts dry extremely quick (not cure, just dry as in haze).

The TCNA handbook is extremely helpful in guiding you to successful installs. However, products change so quickly, they can't always get the info out fast enough. They back up all their recommendations with stringent testing. Sometimes, you just need to be a bit smarter than the rules. I have gone rogue at times but I also have libraried an awesome list of tech support folks that will allow me to throw my crazy ideas out there and together, even between different manufacturers, have come up with solutions we are satisfied with the success potential.

Don't forget, with tile installs, it's all about getting that successful install percentage as high as possible. There are always so many environmental variables, you can't use black & white rules on every situation. But as I always say in the end, it isn't rocket surgery, just tile. You _can_ do it


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## tjbnwi (Feb 24, 2009)

Love CQ grout. As mentioned, it can bite you in the ass quick....

Tom


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## Seven-Delta-FortyOne (Mar 5, 2011)

Thanks for that response. 👍

My current project of two bathrooms with tub surrounds was done with 2 coats of RedGard over cement board, seams taped with the alkali resistant mesh tape, and I caulk the the seam between the board and tub with 100% silicone before installing tile.

Im using Prizm grout. Guy at the role wholesaler recommended it, so I figured I’d give it a shot. Usually I just use the standard cementitious grout.

The 100% silicone color matched caulk showed up today so I’m using that at traditions and corners. It’s a commercial grout caulk from Custom, and it’s a pain in the ass to apply, but it appears very heavy duty

Guess I’ll see how well it holds up.



Is a grout release always used with urethane?

Does urethane haze over like cementitious grouts?


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## angus242 (Oct 20, 2007)

Seven-Delta-FortyOne said:


> Is a grout release always used with urethane?
> 
> Does urethane haze over like cementitious grouts?


Don't mix up FlexColor with urethane (Bostik QuartzLock). Mapei doesn't have a urethane grout.

Bostik has never actually recommended a grout release to me. Mapei did for certain applications. I've actually installed some tiles that required it no matter what grout you install.

Bottom line, you need to be educated on either grout _before_ installing. Grout release is more like having a net under you when tightrope walking. 

When you get to the premixed grouts, you must clean _way_ quicker. If you don't, they haze and haze quickly. And that haze is no joke. If it dries, you might not get it cleaned off without a chemical. 

But I'd seriously consider getting rid of cementitious grout. There is no benefit to it. I don't even consider the cost an advantage because it's SO inferior to the newer grouts. Seriously, it's like framing a house with a hammer; yeah, they used to but no one would do that now.

Again, it's not black diamond level skiing here. The biggest hurdle is getting your mind off the old way of installing grout. Once you realize there's just a different set of rules, it's not hard at all.


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## rrk (Apr 22, 2012)

angus242 said:


> Don't mix up FlexColor with urethane (Bostik QuartzLock). Mapei doesn't have a urethane grout.
> 
> Bostik has never actually recommended a grout release to me. Mapei did for certain applications. I've actually installed some tiles that required it no matter what grout you install.
> 
> ...


Great to have you back, lots of good info


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## tjbnwi (Feb 24, 2009)

Another option, build showers without corners.....

Tom


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## angus242 (Oct 20, 2007)

Geometry!


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## tjbnwi (Feb 24, 2009)

angus242 said:


> Geometry!
> View attachment 510404


Round is a shape, my _waste_ line is living proof......

Tom


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## Klink (Sep 24, 2021)

angus242 said:


> Using the correct grout, I will never use silicone in corners be it horizontal or vertical.... I moved forward to Mapei Flexcolor CQ. They do _not_ crack. The worst that happens is it separates. ....
> I've been through hundreds of buckets of the mentioned grouts and had maybe 12 call backs since around 2006. I've had zero call backs for failed silicone because I don't use it.


You do not caulk between bath tub and tile either?


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## avenge (Sep 25, 2008)

Klink said:


> You do not caulk between bath tub and tile either?


What's your trade?


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## Seven-Delta-FortyOne (Mar 5, 2011)

Forgot about this thread.

The color matched silicone was great, except that it was an absolute nightmare to install. Almost impossible to tool properly.

Ive been swamped all summer with foundations and framing.

Ive figured out how to get real good tile showers corners: SUB THEM OUT!! 🤣🤣


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## natestar (Dec 11, 2020)

We've been using schluters profiles for a while now for corners and transition movement joints. May be worth looking into.









Cove-shaped Profiles | Schluter


Schluter cove-shaped profiles are practical for treating floor-to-wall or wall-to-wall transitions. DILEX profiles accommodate the use of any tile line.




www.schluter.com


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## Klink (Sep 24, 2021)

Klink said:


> You do not caulk between bath tub and tile either?


I am just a homeowner re-grouting a bath tub and shower walls using Mapei Flexcolor CQ and was curious to know if the gentleman in the quote who said he does not use caulk, applies to to the tub to tile connection.


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## avenge (Sep 25, 2008)

Klink said:


> I am just a homeowner re-grouting a bath tub and shower walls using Mapei Flexcolor CQ and was curious to know if the gentleman in the quote who said he does not use caulk, applies to to the tub to tile connection.


This site is for professional contractors visit DIY Home Improvement Forum


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## obaidk (Sep 17, 2021)

i have used Mapei Grout and till now there is no issue comes up. as for as your question is concerned Prism stain grout is a cement based grout so once you are going to add it above the old grout it will not work. if you are still want to use it then check the coverage chart for how to use it i hope it will be helpful for you. Thanks!


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## JFM constr (Jul 26, 2014)

Years back on the old JLC forum .A guy who did expert witness in building cases talked about caulking problems .He said he saw a lot of problems when caulk was used on the horizontal joint between tile and tub .this needs to be able to drain and on his building projects he grouts and said you just have to redo after awhile . Food for thought ,something i hadn't thought of before he pointed it out .


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## Seven-Delta-FortyOne (Mar 5, 2011)

JFM constr said:


> Years back on the old JLC forum .A guy who did expert witness in building cases talked about caulking problems .He said he saw a lot of problems when caulk was used on the horizontal joint between tile and tub .this needs to be able to drain and on his building projects he grouts and said you just have to redo after awhile . Food for thought ,something i hadn't thought of before he pointed it out .


I always do weep holes on the tub-to-tile caulk. 👍


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## MarkJames (Nov 25, 2012)

Seven-Delta-FortyOne said:


> I always do weep holes on the tub-to-tile caulk. 👍
> 
> That sounds kinda crazy. Got a pic?


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## CarpenterRN (Dec 3, 2009)

JFM constr said:


> Years back on the old JLC forum .A guy who did expert witness in building cases talked about caulking problems .He said he saw a lot of problems when caulk was used on the horizontal joint between tile and tub .this needs to be able to drain and on his building projects he grouts and said you just have to redo after awhile . Food for thought ,something i hadn't thought of before he pointed it out .


I believe that applied more to the typical cement grouts rather than the newer, stain-resistant grouts that have much lower permeability.


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## CarpenterRN (Dec 3, 2009)

Seven-Delta-FortyOne said:


> Forgot about this thread.
> 
> The color matched silicone was great, except that it was an absolute nightmare to install. Almost impossible to tool properly.
> 
> ...


I use color match silicone exclusively. It's not bad once you get used to it. I tape off both sides of the joint with 1" blue tape, run the bead using just enough to fill the joint a bit proud, strike the bead with a dry finger, slowly pull the tape at an angle away from the joint, then strike the joint again with a finger dipped in soapy water to clean-up the edge left by the tape. On occasion, there is some additional work/clean-up if there was too much caulk applied that strays outside the joint, but that can be remedied with a rag over a 5in1 or scraper and a little re-smoothing of the joint with the soapy water. I'll take some pics next time.


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## Pounder (Nov 28, 2020)

I've never used anything but grout in corners.


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## Tech Dawg (Dec 13, 2010)

Seven-Delta-FortyOne said:


> Forgot about this thread.
> 
> The color matched silicone was great, except that it was an absolute nightmare to install. Almost impossible to tool properly.
> 
> ...


Masking tape is your friend for nice joints in a shower. I'm still using full bostik grout tho for showers and haven't had any problems.


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## G&Co. (Jul 29, 2020)

JFM constr said:


> Years back on the old JLC forum .A guy who did expert witness in building cases talked about caulking problems .He said he saw a lot of problems when caulk was used on the horizontal joint between tile and tub .this needs to be able to drain and on his building projects he grouts and said you just have to redo after awhile . Food for thought ,something i hadn't thought of before he pointed it out .


That is correct. I have seen many caulked bottom joints (tile to tub and tile to shower fiberglass floor) where water had nowhere to go and migrated sideways. That causes drywall damage just outside the tub/shower.
Bottom horizontal joint should be grouted with permeable grout or have weep holes or another means for water drainage. In the old days this was recognized as a maintenance item and good installers buried a string behind the grout. When the grout started to crack, you just pulled the string and the whole line of grout came out so you didn't have to spend a lot of time digging it out.


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## Terrischwartz (7 mo ago)

angus242 said:


> Don't mix up FlexColor with urethane (Bostik QuartzLock). Mapei doesn't have a urethane grout.
> 
> Bostik has never actually recommended a grout release to me. Mapei did for certain applications. I've actually installed some tiles that required it no matter what grout you install.
> 
> ...


What’s different about how Mapei Flexcolor is installed vs traditional grout? I’m about to give it a try after removing old cracked grout around a bathtub.

Thanks, Terri


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## Leo G (May 12, 2005)

This site is for professionals to discuss contracting. We have a sister site for DIYers


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