# Mastic/thinset bathtub/shower surround?



## angus242 (May 1, 2008)

You cannot use any type of premixed thinset (mastic, etc) in a wet location. :no:

Some advice, when you trowel the thinset on the wall, do it in a horizontal pattern as opposed to vertical. Horizontal lines will help hold the tile to the wall a bit better. Think of it as tile hanging from a rope (horizontal):yes: or sliding down a rope (vertical):no:.


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## ponch37300 (Nov 27, 2007)

Everything i have ever read says not to use mastic in wet locations. Not sure if it is necessary or not but i have also read to use a water proofer like red guard over the whole encloser. Also make sure you use alkali resistant screws and tape, not regular fiberglass drywall tape.


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## jerryh3 (Dec 10, 2007)

angus242 said:


> You cannot use any type of premixed thinset (mastic, etc) in a wet location. :no:
> 
> Some advice, when you trowel the thinset on the wall, do it in a horizontal pattern as opposed to vertical. Horizontal lines will help hold the tile to the wall a bit better. Think of it as tile hanging from a rope (horizontal):yes: or sliding down a rope (vertical):no:.


I'm looking at a bucket of Mapei Type 1. It only states it should not be used in areas that are subjected to constant immersion. This kind of leads me to believe that Mapei endorses it for shower or tube wall use. I know older mastics had problems with re-emulsification(word?) in wet areas, but haven't they gotten much better with the new adhesives?


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## angus242 (May 1, 2008)

I cannot stress this enough, mastic of any type should not be used in a wet location. 

This statement is from the technical director of the Tile Council of North America:
"The tile industry neither condones or recommends mastic or greenboard in wet areas. In the US we have installation standards of which the manufacturing community is one of 4 segments represented. The Tile Council of America publishes (but does not set) the standards (www.tileusa.com)."

Type1 mastic says is can be used in a wet location but that's only because it meets certain minimal requirements under some standard. That's not to say it's OK for all uses. From what I'm told, it's more like setting tile in a commercial bathroom scenario where the longevity isn't necessarily an issue. Most commercial buildings get remodeled more often than a residential situation. 

If my advice isn't enough, use the search feature on this site. Look for replies from guys that have decades of experience like Bud Cline and JazMan. Do a search on John Bridge's website about it. Or, just use mastic that many tile professionals have said not to use, and WHEN it fails, come back here and post your story. I promise not to say I told you so. :whistling2:


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## jerryh3 (Dec 10, 2007)

I went to the site and something caught my eye:

*Does the TCNA approve certain methods?*

The TCNA does not approve nor disapprove methods. As you know, the Tile Council of North America publishes the TCA Handbook for Ceramic Tile Installation. However, as the Handbook secretariat we do not create these details - rather, they are the work of the Handbook Committee, a representative group of experts in the ceramic tile industry. This group meets to share knowledge, problem, solutions, and research. When there are conflicting opinions, the Handbook may not have a solution as it reflects consensus views and generally accepted procedures. Also, the Handbook does not contain proprietary methods. As the secretariat, we record and publish the consensus of these experts.
There are many proprietary methods on the market that are well regarded and backed by their manufacturers. In many cases, proprietary methods and products have been developed to address special conditions or to utilize new technology. These methods will not be in the TCA Handbook but may work quite well when used in accordance with the manufacturer's instructions.

*To find out if any method is appropriate for certain conditions and to find out warranty and application information, you will want to speak with the manufacturer. *



Since the Manufacturer, "Mapei", endorses it product for wet areas, isn't the TCNA endorsing this installation method?


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## angus242 (May 1, 2008)

jerryh3 said:


> Since the Manufacturer, "Mapei", endorses it product for wet areas, isn't the TCNA endorsing this installation method?


No. They don't endorse _or_ condone. 
I'm saying tiling professionals are the ones condoning.

Use what you want. Recommend what you want. I'm telling you as a tiling professional, I say don't use it as do some of the most experienced tiling professionals I know.


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## jerryh3 (Dec 10, 2007)

angus242 said:


> No. They don't endorse _or_ condone.
> I'm saying tiling professionals are the ones condoning.
> 
> Use what you want. Recommend what you want. I'm telling you as a tiling professional, I say don't use it as do some of the most experienced tiling professionals I know.


I'm not disagreeing with you. I'm just trying to find out the basis on why it's not recommended. I respect what professionals recommend and the advice they give, but I like a little more than "I read somewhere..."


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## angus242 (May 1, 2008)

http://www.johnbridge.com/vbulletin/showthread.php?t=39491

http://forum.doityourself.com/archive/index.php/t-191460.html

http://www.johnbridge.com/vbulletin/showthread.php?t=46430

http://www.h o u serepairtalk.com/f13/premixed-adhesive-grout-633/ (remove gaps from link, wouldn't appear otherwise)

http://www.floorstransformed.com/ceramic-tile-forum/2004/mastic-vs-thinset-iii-15697.html

http://ths.gardenweb.com/forums/load/bath/msg0715075825250.html


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## jerryh3 (Dec 10, 2007)

angus242 said:


> http://www.johnbridge.com/vbulletin/showthread.php?t=39491
> 
> http://forum.doityourself.com/archive/index.php/t-191460.html
> 
> ...


Ok. I give. I solemnly swear to only use mastic where not subjected to any moisture.


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## angus242 (May 1, 2008)

YEAY!!!! :thumbup:

Honestly, I see no reason to _ever _use it. While it may be convenient because there's no mixing, the cost alone is enough to steer clear. Mixing thinset is not hard. I just don't trust something that's supposed to adhere tiles but in reality, only does it under certain circumstances.


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## Icantinaturner (Dec 30, 2008)

Well thanks guys, and you've convinced me. I was hoping that I'd hear "Tec Invision will work" but I'm going to use Versabond (blanco, for light colored grout :wink and learn to mix the stuff. I'll probably mix half a bag to start and see how it goes.

I appreciate the tips about horizontal troweling and alkali resistant fiberglass tape. I'll Redguard over the screws too.

The Tec Invision goes back to Lowe's tomorrow.


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## angus242 (May 1, 2008)

I'll probably mix half a bag to start and see how it goes.
*Start with much less. Remember, you can always make more but once a large batch starts to cure, it's done.*

I'll Redguard over the screws too.
*Don't forget to do the seams too. 2 coats to be safe. Follow the directions!*

The Tec Invision goes back to Lowe's tomorrow. 
:thumbup:


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## Icantinaturner (Dec 30, 2008)

Thanks again, Angus. I will do the half a bag trick and double the RedGuard first. I have to do the seams first so I'll get a little practice mixing the thinset and that's a plus. :wink:


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## angus242 (May 1, 2008)

Icantinaturner said:


> Thanks again, Angus. I will do the half a bag trick and double the RedGuard first. I have to do the seams first so I'll get a little practice mixing the thinset and that's a plus. :wink:


Be careful. I'm saying to use much less than a 1/2 bag for your first batch. A 1/2 bag is A LOT of thinset. Use less!


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## Icantinaturner (Dec 30, 2008)

angus242 said:


> Be careful. I'm saying to use much less than a 1/2 bag for your first batch. A 1/2 bag is A LOT of thinset. Use less!


I appreciate that. I'll start with *much less* and see how it goes. I'm not out to set speed records and my bride is used to some of my projects taking awhile...

BTW, photos in your album are seriously impressive. Really nice craftsmanship. :yes:


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## Bud Cline (Mar 12, 2006)

Angus are ya out of breath yet?:laughing:


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## angus242 (May 1, 2008)

Bud Cline said:


> Angus are ya out of breath yet?:laughing:


:innocent:


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