How to water proof your tile shower install

20 Replies

When I am installing a new shower, I always use peel and stick tar tape and 6mill plastic visqueen. 

1st peel and stick the tar tape to the studs and stick to the top 1" lip of the base and staple to the studs.

2nd overlay the visqueen on top of the tar tape and staple to the studs

3rd properly attach your hardy board over the visqueen.

I just tried something a little different around a tub install. After I installed MT sheetrock I used 2 coats of Aquaseal waterproofing. It reminds me of the DIY roll on bed liners you can buy. Stuff dries solid. Then just liquid nails the tile straight to it. Seems like it makes a pretty water tight install.

Looks good to me :)  

Be thankful you live in Florida instead of California.  Over there the building code requires you to "hot mop" it with liquid tar.    

Jay the way you are doing it is not waterproofing your surround,thats more of a vapor barrier. To properly waterproof it needs to be between tile and wall such as the membrane that is mentioned or i prefer a product by schluter. Just so you know for the future, the hardi board or durarock boards are NOT waterproof, more like water resistant. Grout,tile and backer boards are not waterproof, you need to use something between the two. 

@Keith Belzner  the method of putting plastic sheeting behind the cement board is acceptable by most codes.  But, like you, I much prefer the topical coatings such as RedGard or the blue version who's name escapes me at the moment.  Easier to apply and you have a solid membrane.

Jon Holdman, Flying Phoenix LLC

I always use Schlueter Kerdi,  expensive but real nice to work with and customize.  Never had a failure yet. 

Sorry fellow rehabbers. Think about the results. When, not if water penetrates the tile and hardiboard. It runs into a 6mill visqueen, which is overlapping tartape....which is overlapping the edge of the fiberglass pan. Thus running, or slowly dripping into said pan. Otherwise, the water that inevitably penetrates the above mentioned Tile and Hardi then settles or drips onto the coatings mentioned above, will end up where? Under the fiberglass base or in the wall turning into mold. 

@Jay H. when using topical coatings with a fiberglass base, the cement board would overlap the flanges of the base.  You would bring the topical coating down the the bottom edge of your cement board. The water penetrates the tile and mortar.  Hits the topical coating and runs down to the bottom of the cement board.  At this point, its below the top edge of the base, so it drops though the mortar to the base and from their into the drain.

If doing a tile base, the schulter drain works well.  You bring the coating down the sides, over your mortar base all the way to the drain.  Then tile over everything.  The schluter drain gives the water a path to the drain plumbing.

Jon Holdman, Flying Phoenix LLC

@jon Holman 

Maybe I should clarify a bit. I'm not saying in lieu of the coatings. I'm saying as a inexpensive last defence barrier. I use the coatings as well jut as you all describe but I also add this method as a final barrier. My fear has been with the effects of the trowels edge on the coating. Also, I don't take the visqueen all the way to the header. To allow for air flow. 

Also, the cement board shouldn't overlap the lip on the base unless you shim the studs, or you will create a curve effect in the hardi. 

First thing to do is get rid of the, plaster & lath, drywall, greenboard and cement board and substitute a material that is water proof backer. Once you do that you can forget about all the vapor barrier, waterproofing behind your backer problems. Your water proofing and your vapor barrier will all be on the correct side.

2nd thing if your underlayments and water proofing don't conform to the TCNA then don't do them. Don't reinvent the wheel, just follow proven building science and you won't go wrong.

http://www.tcnatile.com/handbook-all/910-2014-tcna-handbook-for-ceramic-glass-and-stone-tile-installation.html

@Jay H.  I understand what you are saying about extra protection but how are you attaching the plastic? The cement board? With screws correct. you have just compromised your install and allowed a water entry point to damage your studs. Vapor barrier is ok as long as you realize that is what it is. Use what ever type of backer board you want but it needs a solid un-compromised waterproofing to be 100%.  

@Keith Belzner 

I think you may be confusing "vapor barrier". This isn't a sealed or compartmentalized application. The visqueen is open at the top. As for the screws into the studs. I apply a shot of 100% silicone to each screw whole. Since there is a pocket door behind the wall I predrilled my holes because I ground off my hardi screws. Didn't want to scratch the door. The plastic is stapled. 

most if not all of my discovered leaks have come from the seams or inside corners where two hardI boards meet. The visqueen method has no penetrations in the corners, thus giving the water a path to travel back to the pan and drain. 

Originally posted by @Mike F. :

First thing to do is get rid of the, plaster & lath, drywall, greenboard and cement board and substitute a material that is water proof backer. Once you do that you can forget about all the vapor barrier, waterproofing behind your backer problems. Your water proofing and your vapor barrier will all be on the correct side.

2nd thing if your underlayments and water proofing don't conform to the TCNA then don't do them. Don't reinvent the wheel, just follow proven building science and you won't go wrong.

http://www.tcnatile.com/handbook-all/910-2014-tcna-handbook-for-ceramic-glass-and-stone-tile-installation.html

 What's a waterproof backer? 

Backer board directly to studs. Redgard over hardi backer. Then tile with thinset mortar, not the premixed glue. It doesn't last. Also use the smallest spacers you can get away with.

The only time I use a membrane or a coating is when I build a tile lined walk-in with a mud bed pan. And then only go a bit above the curb. A vapor barrier on an interior wall is unnecessary and actually acts to trap moisture in wall and degrade components. 

If you have enough water permeating the tiled walls to actually run down the wall to the pan, you have bigger problems than what a coating or vapor barrier could address.

With full contact of thinset, there shouldnt be enough connecting voids for water to pass. If there us enough water to saturate and wick its way down, you have missing grout or bad caulk job. If you mix thinset to the proper consistency, flat trowel surface then notch trowel it, butter backs of tile, and "beat" tiles into place, you will acheive full contact. IF, and I repeat, IF, water permeates beyond grout, it would simply wick into thinset and dry out. A vapor barrier would inhibit that process.

Stone is not waterproof, ceramic and porcelain are. Cement based grouts are not waterproof, unless properly sealed with a good sealer. But even with an unsealed tiled wall, during a twenty minute shower, there us not enough water soaked into the grout to cause water to run down in wall behind tile. Without a vapor barrier, it dries out in short order.

Before spending alot of cash on sleuter backer, membranes and coaters, Id recommend epoxy grout, which IS waterfroof, doesnt need sealing, and cleans much easier.

Me thinks there is too much over-thinking going on. Ive demo'd tile surrounds that are decades old with NO signs whatsoever of water damage behind tile. Tile set on painted drywall almost always presents with mold between tile and drywall. Why? Because the painted surface inhibits movement of water vapor thru wall. It traps moisture just as a vapor barrier does. 

If you want to beef up your showers and surrounds, install blocking across walls behind tub flanges and behind pan flanges and mid way up wall of walk-in showers. Also, reinforce framing at inside corners with screws. Using ice and water shield or roofing repair/flashing tape at tub and pan flanges under backer IS a good idea but also unnecessary with a proper caulk job.

I prefer Durock as it is structurally superior to hardibacker and has better breathability, but it is a bit more flexible than hardibacker. I always use blocking behind Durock.

Why reinvent the wheel? We've been setting tile for centuries. Follow manufacturer recommendations and industry standards and youll be fine.

Originally posted by @Jay H. :

@Keith Belzner 

I think you may be confusing "vapor barrier". This isn't a sealed or compartmentalized application. The visqueen is open at the top. As for the screws into the studs. I apply a shot of 100% silicone to each screw whole. Since there is a pocket door behind the wall I predrilled my holes because I ground off my hardi screws. Didn't want to scratch the door. The plastic is stapled. 

 A pocket door in a tiled wall sounds like cracked grout in the making. Not enough structural integrity to prevent excess movement in wall.

If moisture penetrates your wall and encounters visqueen, it will act as a vapor barrier because it cannot readily travel to your opening at top. 

Originally posted by @Jay H. :

@jon Holman 

Maybe I should clarify a bit. I'm not saying in lieu of the coatings. I'm saying as a inexpensive last defence barrier. I use the coatings as well jut as you all describe but I also add this method as a final barrier. My fear has been with the effects of the trowels edge on the coating. Also, I don't take the visqueen all the way to the header. To allow for air flow. 

Also, the cement board shouldn't overlap the lip on the base unless you shim the studs, or you will create a curve effect in the hardi. 

Actually, neither the coating nor the flashing will accomplish whats been stated. IF water runs down behind tile, whether it runs over a coating or flashing, it cannot run to drain as it will be trapped by caulk. If it cannot evaporate it will just sit there and break down the thinset over time.

I dont overlap the flange. I set the backer above top edge of flange. Not willing to have my tile tilt out at bottom between 1/4" and 1/2". For that reason I install blocking for stability behind where flange and backer meet. If it makes one feel better, you could caulk that joint, but if I had to build showers and surrounds with water running behind my tile in mind, id change professions.

Originally posted by @Jay H. :

 What's a waterproof backer? 

DENSHIELD made by Georgia Pacific. Simple, simple solution. Waterpoof shower with vapor barrier automatically in the correct location.  You can typically even buy it at Home Depot in many parts of the country which I know will be a big happy face for many here.

Problem solved, no need for all the rigamarole.  Have built a minimum of 1000 showers and have never had a single leaky shower yet. Cement board was a dead product 10 years ago, no reason for it.

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