# Need Advice About Walling for Bath Remodel



## bjbatlanta (Jul 16, 2008)

As long as proper paint is used and you have proper ventilation, regular drywall can be used for baths. Normally for a tile surround, drywall is hung "full" down to within 1/2" of the lip of the tub. Cement backer board is installed over the drywall for tile, giving you a lip at the edge of the tub for a bullnose tile. You can add a layer over the existing ceiling as long as proper length fasteners are used (1-7/8" if you use nails, 1-5/8" if you use screws).


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## oh'mike (Sep 18, 2009)

When I rock a bathroom --I use regular drywall except in the tub area--that gets 1/2" Durrock (or orher backer board) 

I install the Durrock on the studs--stopping at the top of the tub flange--that void below the Durrock is filled with thinset as the wall is tiled.

Water proofing the cement board is always a good and safe option---I like the paint on liquid membranes,like Hydroban or Red Guard.

---Mike---


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## Bud Cline (Mar 12, 2006)

Some form of cement board for the tub surround walls.
If you intend to tile the ceiling you can simply waterproof the existing ceiling with a liquid waterproofing membrane.



> ...greenboard, Hardi Backer tub surround, then flooring last?


Yes, Greenboard, Hardibacker tub surround, then flooring last?

Cement board requires a moisture barrier on the studs unless you waterproof the face of the board, then no moisture barrier is required.

For the shower walls I would suggest Denshield tile backer. No moisture barrier required behind the board and the surface won't wick water like cement board will.

Hardi is fine for the floors.


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## bremdogg55 (Mar 9, 2011)

Thank You to those that responded to my post. I think after reviewing what you have written as well as what I have found elsewhere in this forum, I have decided to use the Denshield for the tub surround where I will be tiling. My thought is that if you do no allow water into the wall cavity, then you dont have to deal with how and where it wicks to. Since I am a car buff, I equate it with the same logic as sealing up your vehicle from water as opposed to allowing moisture in and then drilling a hole in the floorboard to drain it. I know this isnt a perfect analog, but I think it drives the point home.

I do want to just clarify a couple more details with you pros please

1) I DO NOT want a vapor barrier behind the area of walls behing the Denshield, even the one exterior wall that will be tiled?

2)I used Kraft faced insulation on the shower wall that is lengthwise paralell to the tub. Do I need to slit the facing before installing the Denshieldor is it OK to leave it.

3) Can I go right over the top of the Denshield with modified thinset to set the tiling or is there another step involved?

4) The transition from the Denshield to the vertical tub flange has caused me some concern. It appears that the preferred way to do it is to stop the Denshield just above the vertical tub flange and fill in the gap with modified thinset and tile over. Do I need to waterproof the thinset in this area as it would seem that it would be able to allow moisture to get through to the wall cavity since its not waterproofed? OR do I space out the Denshield from the studs (the verical tub flange is 3/16 thick) this thickness and run the Denshield over this vertical tub flange leaving a small gap between the Denshield and the HORIZONTAL surface of the tub and caulk at the bottom, then finish with tile? This is my biggest question and I seem to read about folks doing it both ways.

I am located in the Northwest in Washington State. Although Im not going to live in this house forever, I want to do this in a manner that will produce the longest lasting job, not necessarily the cheapest or quickest as I would expect a good amount of you contractors out there encounter with many customers. My opinion is that there are many ways to accomplish these improvements, but some are much longer lasting and that is the info im after. To put it in a nutshell.... How would you accomplish these improvements in YOUR dream home, not some mass produced homes produced quickly and with minimal expense. You can paint a car 100's of different ways, but if the paint flakes off or bubbles in 3 years instead of 20 years, then it really wasnt a good job. It just looked good for awhile. To put it in my terms..

Thank You in advance to all of those that respond and have responded. 

Greg..

P.S. How on earth can I find out how to post a picture in my posts?


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## Bud Cline (Mar 12, 2006)

> 1) I DO NOT want a vapor barrier behind the area of walls behing the Denshield, even the one exterior wall that will be tiled?


Correct.



> 2)I used Kraft faced insulation on the shower wall that is lengthwise paralell to the tub. Do I need to slit the facing before installing the Denshieldor is it OK to leave it.


I know the "slitting the insulation face-paper" turns up as a recommendation in some places but I wouldn't do it if it was me.



> 3) Can I go right over the top of the Denshield with modified thinset to set the tiling or is there another step involved?


Denshield has a water resistant face coating (unlike cement board). You will need to address the seams and the fastener penetrations to maintain total water resistance. I use mesh tape for the seams and coat it with liquid waterproofing. The mesh will collect the waterproofing and seal nicely. It may take more than one application however. I also paint the fastener heads and holes.



> 4) The transition from the Denshield to the vertical tub flange has.....


Stop the wallboard on the top of the flange, don't go over it. Caulk that juncture totally. In some cases the caulk will resist bonding to a raw edge of Denshield but you can make it stick. Drag your finger through the caulk and stitch it upward into the edge of the board.

Install the tile so as to pass the gap between the wallboard and the tub top. I see no reason to fill the gap with thinset but if you can't live with knowing that void is there then fill it. You will eventually apply caulk to the tub and tile juncture so it really doesn't matter if that void is there or not.

I don't race through any of my jobs and what I am telling you is my current method. I can proudly say that I have never had a job failure of any kind in my thirty-five years of doing this kind of work. Not one.



> P.S. How on earth can I find out how to post a picture in my posts?


Somewhere here there are instructions for posting photos. I have a helluva time doing it myself.:yes: 

What else?


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## Gary in WA (Mar 11, 2009)

Welcome to the forum! 



Post a picture; http://www.diychatroom.com/f98/how-post-photos-using-photobucket-flickr-49655/

OR; http://www.diychatroom.com/f98/how-attach-photo-post-20532/
These are found as "stickies" at the beginning of the "How to" titles. 

Thinset between the backer board/tub could let water through by the different expansion/contraction rates from the temperature changes of the two very different materials and mass thickness, causing a crack there. Also, thinset could wick water through it (capillary action) to the backer core, unlike caulking. I'd use caulking in front of backer rod (for any larger gaps) to have a "hourglass" shape for optimum stretch in case any water gets past the caulking at tile/tub joint. Only two surfaces with caulk, tub/board, not three- tub/board/tub lip. Step #5; http://www.crossroadsci.com/LinkClick.aspx?link=pdfs/13D_Dow%20Corning%20Tub%20Tile%20Ceramic%20Sealant.pdf&tabid=80

Or leave it empty as said. My 2 cents….

Gary


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## tazangel52 (Dec 5, 2012)

so does the mortar for the tile installation stick to the cement board after you apply the liquid membrane product?


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