If you need to decide which method is best for you I have a free shower waterproofing manual that you can download here. Shower waterproofing manual. Go get it – it’s free! And I’m not gonna use one of those damn annoying pop-ups! I hate those things…
There are several ways to prepare the wall of a shower for tile. Depending upon what was originally there, what stage the shower rebuild is currently in, and what type of tile you plan to install plays a minor part in choosing which method to use.
The most critical aspects of which product to choose are: how much work you’re willing to put in and how much money you’re willing to spend. The end result should be the same – a waterproof box. The methods used to accomplish that vary in effectiveness and cost. So we’ll start with what I consider the most bullet-proof method.
Kerdi Shower System
A company called Schluter makes a shower system called Kerdi. The entire system, which can include everything from the wall membrane down to the entire shower base, is considered by many professionals to currently be the top of the line in shower substrates and waterproofing membranes. And no, I don’t work for them. I don’t owe them money. And they don’t take me on those all expense paid vacations to Bermuda – bastards. I like their products anyway.
The waterproof membrane made by Schluter is called . . . well, Kerdi. It’s bright orange and you can see it from space. It is installed over regular drywall or cement backerboard with regular thinset. It makes your shower a big bright orange waterproof box that glows in the dark. Okay, it doesn’t glow in the dark.
The material is difficult to describe with words, it’s kind of like a fleece-lined rubber(ish) membrane. I like it for two reasons: It is the best available and it happens to be the easiest, least work intensive option (once you are used to working with it). While there is a fairly large learning curve to effectively work with it, Kerdi is fairly easy and very well documented. There is a wealth of infomation on the internet about it. Just Google Kerdi. Go ahead, I dare ya. Noble company also makes a similar membrane called NobleSeal, but it isn’t pretty bright orange.
Liquid Membranes
After Kerdi, a brush or roller applied liquid membrane such as RedGard works very well. It is applied with a brush or roller like a thick paint. It’s bright pink. You coat it once, after it changes to red, coat it again. Usually two coats is sufficient for any shower (except steam showers). After is sets overnight just go in and stick the tile to the membrane itself. It is a bit expensive, but they are also simple and quick to install.
There are several of these membranes on the market, the most common being Redgard. My favorite is Laticrete Hydroban. Laticrete also makes Hydrobarrier and Mapei has Aquadefense. They are all pretty much comparable.
Preparing shower walls with RedGard
If you are building a shower and want a manual describing the entire process you can find it here: Liquid waterproofing membranes for shower floors and walls
Cement or Fiber Based Backerboard
If you don’t want to spend the money for Kerdi or RedGard, this is your next best option. These are products such as Durock, Hardiebacker, and Fiberboard. While the product itself is not waterproof, it is water-resistant. The backerboard will actually hold water, as in water will soak through it. There needs to be a vapor barrier put up between the wall studs and the backerboard.
The unique thing about these products is that, although they are not waterproof, they will not become unstable with moisture. (That just means water doesn’t make it swell up.) To use these you must first install some type of moisture barrier over the wall framing. Get a 4 mil or thicker plastic (mil is just the thickness of the plastic) which can be purchased at places like Home Depot, and staple it to the studs of the wall framing. You can also adhere it to the studs using silicone. Completely cover all areas from the tub to the ceiling. The backerboard is then screwed onto the studs to make your shower walls. Then you just stick the tiles to the wall and shower away.
I also have a couple of manuals describing the entire process from the wall studs all the way up to a completely waterproofed shower substrate ready for tile. You can find them here:
Waterproof shower floor and walls manual
If you have a tub or pre-formed shower base and need to only do the walls you need this manual:
Waterproof tub and shower walls
Denshield
Denshield (and others like it) are similar to drywall in that they are lightweight and easy to install. It is a waterproof core laminated on each side with a fiberglass based face. It is installed like drywall except you need to run a bead of silicone between the sheets to waterproof the seams. You then need to use fiberglass mesh tape over the seams. It does not require a moisture or vapor barrier behind the sheets. When properly installed Denshield is an adequate tile substrate for shower walls and relatively affordable compared to alternative methods.
If you are building a shower and want to use a topically-faced wall substrate you can find that manual here: Building a shower with a traditional floor and topically-faced wall substrates
If you are just tiling around a tub or pre-formed shower pan you can find that manual here: Topically-faced wall substrates for tubs and shower walls
Plain Drywall *DO NOT DO THIS!!!
Yes, you can do it if you must. I absolutely do not recommend this! But I’m also realistic enough to know that if you decide this is what you’re going to do, I’m not gonna be able to stop you from here. You can not just go up to your drywall and start sticking tile to it – ever. There needs to be a moisture barrier between the drywall and the framing. At least then when water gets behind your tile and grout and disintegrates the drywall it won’t disintegrate your wall framing as well. Remember, if water gets to one of the studs not only will you be replacing the shower, you will need to do some serious repair work to your wall framing and possible structural work. Please also note that using this method runs the risk of parts of your wall literally falling apart if it gets wet – drywall disintegrates in water.
And it will. So don’t do this!
Unsuitable substrates for shower walls – no matter what you’ve been told
- GreenBoard, also known as green drywall. Never use this or you’ll get a lot of practice replacing showers.
- Backerboard without a moisture barrier.
- Drywall without a moisture barrier. (I do not recommend drywall as your substrate at all.)
- Any type of plain wood or plywood. Ever. No, painting it makes no difference.
I’m certain there are a lot of things I’m not thinking of that someone else will. If you wouldn’t let it set in a swimming pool for a week, don’t use it for your shower walls. That should clear it up.
The golden rule
Although there are many products that can be used for your shower wall, many should not be. Regardless of which method you choose one thing to keep in mind is that you need to have some type of waterproof membrane between your tile and your wall framing. Kerdi membranes and RedGard are both waterproof membranes that go directly on the wall. Plastic stapled to the frame before installing your substrate is also acceptable.
The main thing you need to ensure is that no water reach your wall studs – ever. Wood swells with moisture and the only place that excess swelling is going to go is right into the back of your tile. Remember, your tile is not waterproof so you want to adhere your tile to a substrate that is as waterproof as you can make it.
If you need to decide which method is best for you I have a free shower waterproofing manual that you can download here. Shower waterproofing manual. Go get it – it’s free!
We have a very small, slow leak in our 4 year old tiled walk-in shower. There are cracks in the vertical corner grout seams – which we think may be the culprit. We’ve also found that there was not a moisture barrier used behind the cement walls and the cement walls sit inside the copper shower pan. We have been in contact with the installer and he appears to be puzzled over where the leak is coming from (not the drain as that is tight). Since there is not moisture barrier between the cement board and studs, would you say that is the problem? How can this be fixed short of tearing out the shower?
Thanks, Shelly
Hi Shelly,
The leak is a result of no moisture barrier. The cement board needs to have a moisture barrier behind it directly over the studs and running into the copper pan. The lack of that is what is causing the leak. The cracks in the vertical corners are simply the easiest way for water to get into the wall. Once that happens you will not stop it. Tile and grout are not waterproof! Water will get behind your tile. The cracks are simply making it happen much more quickly and it is likely that the damage you can see is far less than the damage in the wall that you cannot see.
Short of tearing out the shower? Nothing, really. You can silicone the corners which may slow the leak, but it will not stop it. The cracks are not the sole source of water for the leak, simply the fastest source. Water will continue to migrate into the framing where it is currently being sucked in – it will simply do it more slowly and less noticeably. That also means more damage with fewer visible signs. With no moisture barrier or any other type of waterproofing your shower was not waterproofed. Your shower walls need to be waterproofed. Tearing it out and rebuilding it properly is the only way to do that.
Should you tile the floor under the bathtub before setting the tub, and if the tub has already been set, is there something special that should go around the edge of the tub before the tile is installed?
Hi Gloria,
No, tile up to the tub, never under it. If you tile under it you can never remove the tile if you want to replace it and it leads to problems if you ever have plumbing issues. Leave about a 1/16″ space between the tile and tub and silicone it when you’re finished.
All the above has bneen a good read however, noone has mentioned using tar paper below the hardy backer as a membrane. My contractor just put some up under the first wall above the tub! I asked if tar is supposed to be used inside especially in such a small bathroom ? could this off gas and be quiet unhealthy?
I’m glad I noticed now before any more goes up.
Sure hope to hear from you soon?
thanks!
Hi Valerie,
The tar paper you refer to is likely roofing felt. It is an acceptable and approved product to be used as a vapor barrier. It is actually better than regular poly plastic because the pores in the membrane swell and close up when subjected to moisture or vapor. It has been used in showers, literally, for over 100 years. It was the original barrier beneath a mud shower. I have never heard of any offgassing or similar problems with it. I’m certain that if that were an issue professionals in the industry would have heard about it long before now. It’ll be just fine. Really.
Hiya thanks for great info! Is it overkill to use durock then kerdi over top?
guv
Hey Guv,
Define overkill.
Not necessary, but not necessarily overkill either. Simply another viable method. In steam showers durock is required beneath kerdi. If it helps you sleep at night then it isn’t overkill – it’s preventive medicine. 
1/2″ ultralight drywall and kerdi for shower. Will 1/2 ultra light drywall be suitable for a tiled ceiling when covered with kerdi? The ceiling is 3′ by 4′.
Hey Lonnie,
It should be fine provided your ceiling joists are located 16″ o.c. or closer.
Roger the super elf…. Thanks a million. I’ve ready your book. It is the best out there.
I would have written a book also…. However I can’t spell… see post above.
LMFAO! Thanks Lonnie, I’ll keap an i owt fer yer buch.
Hi Roger,
I realized the tile I fell in love with has the grey design on top of a red/brown. I am worried that the red/brown will show on the sides of the shower, should it be covered with caulk, grout, or should I find a nicer tile that isn’t made from the red/brown base?
Also, there is a 1 1/4″ gap between the tub and and hardie, should I have my contractor remove the hardie and put plywood up the entire wall to reduce the gap? I’m worried if he tries to use grout it will crack and caulk will eventually mold, any other ideas?
One more question, if the tile in the shower goes all the way to the ceiling the hardie should go to the ceiling too, right?
Thanks!
Michelle
Hey Michelle,
You have a clay-bodied ceramic (that’s the red/brown part). Most ceramic tiles have matching bullnose tiles available. These are normally 3″ x 12″ tiles with a rounded over edge that is finished. The rounded part is placed on the outside and runs the color of the tile (gray) all the way back to the wall rather than seeing the red edge of the tile.
That will crack – guaranteed! The tub should be moved back against the studs of the wall, or the wall studs need to be built out to meet the tub. Ideally the hardie should be over the upturned flange on the back of the tub. That gap cannot stay there, water will end up down in it THROUGH the grout (grout is not waterproof).
Technically it doesn’t need to go higher than the shower head, although it’s always best to have backer behind everything in the shower that’s tiled. It won’t negatively affect anything at all up that high, though.
Can you elaborate a bit on why you don’t like the greenboard in this application? I’ve had multiple contractors tell me that’s what to use for a surround. Usually, they’ll say something like “The Hardiebacker is better, but the water-resistant drywall is pretty good.”
Hey Mike,
Certainly. Basically ‘greenboard’ or water-resistant gypsum board is no longer an acceptable substrate for tile in any wet areas. Notice it is described as water ‘resistant’ – not water proof. The paper face on the gypsum is not waterproof. Once water or moisture hits it, the paper will begin to wick water. Once that happens the face (paper) will become delaminated from the gypsum core, which will then break down. Once that happens mold will begin to grow.
The International Residential Code (IRC) has determined that effective January, 2006, paper-faced greenboard will no longer meet its standards as an approved tile backer substrate for wall tile in wet areas such as tub and shower areas.
R702.3.8 Water-resistant gypsum backing board. Gypsum board used as the base or backer for adhesive application of ceramic tile or other required nonabsorbent finish material shall conform to ASTM C 630 or C 1178. Use of water-resistant gypsum backing board shall be permitted on ceilings where framing spacing does not exceed 12 inches (305 mm) on center for 1/2-inch-thick (13 mm) or 16 inches (406 mm) for 5/8-inch-thick (16 mm) gypsum board.
Water-resistant gypsum board shall not be installed over a vapor retarder in a shower or tub compartment. Cut or exposed edges, including those at wall intersections, shall be sealed as recommended by the manufacturer.
R702.3.8.1 Limitations. Water resistant gypsum backing board shall not be used where there will be direct exposure to water, or in areas subject to continuous high humidity.
The new requirements are (as of January 2006):
R702.4.2 Cement, fiber-cement and glass mat gypsum backers. Cement, fiber-cement or glass mat gypsum backers in compliance with ASTM C 1288, C 1325 or C 1178 and installed in accordance with manufacturers’ recommendations shall be used as backers for wall tile in tub and shower areas and wall panels in shower areas.
Whoever has told you that is apparently not familiar with the IRC code changes nor the propensity of that board to wick water, break down and grow mold. I don’t feel it is anywhere close to ‘pretty good’.
I just happened upon your site – great stuff and thank you for all the time you spend answering everyone’s questions! Here are mine – So which method of waterproofing do you recommend? Membrane versus hot-mopping camps appear to be the tiler’s form of Democrats versus Republicans! Each side believes they have it right and that the other is wrong…
Only today I learned from one contractor about waterproofing by putting down layers of fiber glass, with ‘I cannot remember what’ in between… Till then I had only heard of prefab fiber glass shower pans.
Does the Kerdi system involve a type of membrane? If so, what makes it superior to the kind found at places like Home Depot?
Hi again!
I just read my email and found a reply from another contractor who says he uses a product called ‘chloriloy,’ which is some sort of rubber membrane. How would you rate this material compared to the Kerdi (and Wedi, which I have also been hearing/reading a lot about).
The guy who talked about the layers of fiberglass (which I mentioned in my previous post) said that it is 3x the cost of hot-mopping, but that it will essentially last forever (30 yrs+), while HM may last about 15- 20 yrs! He said the membrane from HD/Lowes is lousy, but had not heard about Kerdi and did not appear to want to try anything new since he feels he has the best system in town… I would have no problem with it if I knew enough to agree that it really is the best way to go, but I do not – so like everyone else, I’ve come to the Guru!!
Thank you much!
Jen
Hi Jen,
I’m an independent.
Both work well provided they are installed correctly. I prefer topical membranes for a couple of reasons, first and foremost being that no part of your substrate ever gets wet – ever. The waterproofing is directly beneath the tile. However, traditionally built shower systems work very well also. Fiberglass waterproofing is an option but that’s actually one that I don’t think is necessary in most applications. I do not like hot-mopping, but it’s likely simply because I’m not very experienced with it and it isn’t a common form of waterproofing in my area of the country. That being the case I really can’t speak to the durability of it, I really don’t know.
HD/Lowes membranes are normally pvc-based sheep membranes whereas Chloraloy is a CPE membrane. They both also work effectively provided correct installation. All of the above mentioned products deal with a ‘traditional’ shower build which incorporates a waterproofing membrane over which your substrate is installed, then tile.
Topical membranes, on the other hand, utilize a substrate with the waterproofing over it, then tile. These are products like kerdi, redgard, and wedi. Have you downloaded my shower waterproofing manual yet? It’s free and it will explain all this stuff very simply. Grab a copy of that and give it a read and you’ll likely know more about it then most contractors.
You can do that here: Shower Waterproofing Manual
I am renovating my tub surround. It used to be a plastic surround that the previous owner had installed, but some of the panels never stuck completely to the wall and there was LOTS of caulking around it. We tore it off the wall and found that globs of glue still on the wall, which is cement board by the way). I have been chipping away at this glue for a while now but not all of it comes off. Am i able to tile over the glue if i can sand it almost flush with the wall? Will the mortar hold on this glue or even on a painted wall?
Hey Robert,
It is always best to remove all of the glue before attempting to thinset anything over it. Glue and like products are called bond-breakers, that’s exactly what they do. Thinset will usually not be able to grab onto those spots well enough to adhere the tile long-term. You can go over a painted wall provided you rough up the surface first. Try stealing your wife’s hair dryer and apply heat to the glue. Many times that will soften it up and you can get it scraped off that way – then sand over the spot where it was.
DO I USE 1/4 OR 1/2 INCH BACKERBOARD BEHIND MY SHOWER WALLS, WON’T THE 1/2 INCH PROJECT THE TILE OUT FARTHER THAN THE WALLS OUTSIDE THE SHOWER OR DO I JUST USE BULLNOSE AT THE ENDS TO MAKE IT LOOK NEAT
HI jAN!
THE TILE WILL NORMALLY STICK OUT FURTHER THAN THE WALL, BULLNOSE IS USUALLY USED AT THAT TRANSITION.
(Your caps-lock seems to be dyslexic)
I’m ready to begin tiling my shower. A custom fiberglass shower pan has been installed and I purchased hardibaker from home depot. But not sure how to handle the waterproofing. My shower & my tub are partially on outside walls with insullation. The other walls are inside walls with no insullation. I’ve read that I shouldn’t put the plastic over the insullated walls. What do I do?
Hi Carolyn,
You can install the vapor barrier over the insulation. If it is ‘faced’ insulation (it has the paper over the front of it) then you’ll need to simply cut some slits into that paper in order to allow vapor behind the barrier to dissipate and not be trapped between it and the barrier, that may lead to mold. Just cut some slits into the facing and tile away.
Final questions….maybe. The fiberglass comes up 10″ on the back and side wall and covers the entire 36″ pony wall. The guys that installed it said not to put any holes in it and to glue the backer board to it. 1. What kind of glue will hold the backer board to the pony wall since I’m not suspose to put any screws in it? 2. Is there a specific pattern that I use to avoid trapping water? 3. How far down do I glue?
Hi Carolyn,
Not sure what type of fiberglass you are speaking of? There shouldn’t be any fiberglass behind tile or backerboard that I am aware of. Can you elaborate a bit on the details?
Don’t see my reply so not sure it went through. I did reply to your email with pictures since I can’t tell how to send them via replying to the post. There is a cfoncrete mud base that was sloped to the center drain. The fiberglass resin was applied to that. On the sides there are solid fiberglass panels and a resign was applied over that. I’m including a website that a picture of basically what was done. http://cdn.njfiberglassdeck.com/wp-content/uploads/CIMG0066.jpg The pictures I sent via email are of my bathroom and shows how far up the fiberglass goes.
Hey Carolyn,
It went through, and I did get your email. You know, I’ve never actually seen one of those so I really can’t tell you what you need to use to install the backer to it. I would think that without mechanical fasteners (screws) into it that the only thing that would reliably attach to it would be epoxy. But I could be incorrect, there are many different types of fiberglass coatings so you may have one on there that will adhere to a different material. Your best bet would likely be to contact the contractor who installed it and ask him what you need to use.
I plan on building a shower stall using durock as the substrate, and then applying redgard as the waterproofing layer. My question is if the ‘rubbery’ surface crated by the redgard will be a good bonding surface for the thinset…it seems like the durock would be better for applying thinset, as it is cement to cement, not cement to rubber( or whatever redgard is). Thanks
Hey Kevin,
Redgard is an elasomeric membrane. That”s just a fancy-ass term for a specifically formulated rubber membrane. Part of that formulation is to allow the portland crystals in the thinset to adhere tenaciously into the membrane itself. It’s made for it, and it works very well.
Is it OK if I use 1/2′ Durock on the walls, but use Densshield on the ceiling? (I like the fact that it’s significantly lighter). Can I also Redgard the Densshield, even though it has a waterproof skin?
Hey Kevin,
Yup, no reason not to do it that way. And I honestly don’t know if redgard will adhere to the denshield well enough to support tile so I probably wouldn’t trust it. Both are waterproof, it’s the bond of the redgard to the substrate I’m worried about, it may be a weak link – not something you want in a tile installation above your head.
hi Roger,
installed my 1×1 shower floor and left on one side a gap that I siliconed about a 1/2 inch between tile and hardi. Thought that my wall tile would cover gap on bottom row and in certain spots it is even or a hair out where bottom tile and floor tile meet with( 1/8 to 3/16 gap). The walls are up and floor is grouted. Walls are not. Should I chip out the small tiles where this has occurred or just insert caulking and grout when I do the wall area.
When I did the floor I left small gap between hardi and tiles but left larger gap on this one side and thought the bottom wall tiles would completely cover. Only I can notice this so wondering what your thoughts are?
Also, hardi to drywall on top of shower. Bullnose transition. Bullnose seems to have larger ridges on back to make thema bit thicker when next to regular tile and may have slight lippage.
Thank you for all your unlimited knowledge.
Dick
If it is 3/16″ in only a few, small spots just go ahead and caulk that in. No one is going to notice it except you – stop looking at it.
The bullnose pieces are normally cut from full tiles and bullnosed. It probably doesn’t have bigger ridges, it’s probably just bullnosed on the edge that wasn’t an outside edge initially. You can usually make up for that with thinset.
Hi Roger,
Just a big thanks. I have asked atleast 20 questions throughout my renovation of shower stall and all were answered. You have gone above and beyond. I now feel vey comfortable with all areas(probably not true). I look at many of the questions others send in and can answer because of your patience with me.
I used vapor on my project but my daughter bought a home and would love to attempt kerdi walls( I know more questions would follow to you) That’s for another day.
THANK YOU FOR EVERYTHING. I will continue to get knowledge from you even though I am DONE.
You’re very welcome Dick. Enjoy your new bathroom!
Hello….if the walls are properly waterproofed (i.e. Redgard) what happens if there is water penetration behind the tile? Does it migrate down the waterproof wall until it drips into the shower pan?
Once it hits the redgard gravity pulls it down into the pan.
My apologies if this question is ridiculous, but if the (waterproofed) backerboard has been covered with thinset, how does the water migrate down. I guess I am having a difficult time envisioning how water will run down between tile and substrate when it should be completly full of thinset
Hi Kevin,
Water travels through thinset, as well as nearly every other cement-based product. Think about your driveway when it rains, it gets dark. It does that because it soaks in water. As it dries it will get lighter. While a small portion of the drying process is due to evaporation from the surface, most of it actually drains into the ground beneath the driveway by running through the concrete. Water does the same thing behind your tile – gravity pulls it down out of the thinset.
Oh, and your question wasn’t ridiculous.
Thanks for all the information your web site provides….I’ve learned so much. Thankfully I stumbled across it before starting my reno…..Cheers…..
You are very welcome Kevin! Glad I could help.
Hi again, so many places for so many questions! Please tell me where to start tiling my shower. I figure I must start at the bottom and go up, but how about from front with whole tiles or the back? I can’t seem to find it within your site. Great and entertaining info! Thanks for your trouble. gigi
Start on the back wall at the bottom and go up. The sides start with a full tile on the outside edge of the shower and work towards the back wall, cutting the last piece to fit in the corner.
Hi Roger!
Question. I’m using Denssheild for my remodel. Since you state above “does not require a moisture or vapor barrier”, does this mean I don’t need to use Redgard?
Thanks for all of the great info you’ve provided!
Hi Leah,
Yes, it means you don’t need redgard. The denshield already has the waterproofing membrane on the face of the board. You do need silicone in all the seams to fully waterproof it, though.
Hi Roger,
Awesome Website for us weekend/evening warriors!!
I am remodeling my bathroom and yes, you’ve guessed it I have a couple of questions. Right now my walls are down to the studs and I plan to put in a tile shower floor, walls, and ceiling. I am getting a custom made fiberglass shower pan that I can tile right on to it. For the walls, I was told to use cement board to tile onto, so I was going to put 1/4″ mold resistant board on the studs first, then put 1/4″ cement board on top, so i can tile on. I am thinking, (and sometimes that is not good) that the cement board is not going to be a water barrier. So my first question is, Do I need to install a membrane on the walls? when should i install the membrane? Thanks for your knowledge!!
Hi Damian,
There is absolutely no need for the mold resistant board. You need to install a 4-6 mil plastic membrane over your studs, then install 1/2″ backerboard over the top of it. Using the two layers of different material may lead to problems you are attempting to prevent. And you are correct, the cement board is not a barrier.
Excellent shower handbook by the way, that is the first time i have gotten drunk drinking choc. milk!
it did answer a lot of my questons. thanks again for the help 
I’m going to install the Schluter Kerdi shower. Does the sheetrock need to be primed before using the thinset to install the Kerdi material or can you use the thinset directly on unprimed sheetrock?
Hey John,
You can do it right over unprimed drywall. Just make sure you burn it in first with the flat side of the trowel first, then install as normal.
Quick question for you… I have my shower stall ready to tile. We have a fiberglass pan that has the 2-3″ lip that goes up each wall and butts up to the backerboard. When I begin to tile, how far down should I bring the first row over that lip? And do I fill the small space beneath it with caulking or grout??
Hi Sandra,
Take it all the way down over it to within about 1/16″ – 1/8″ from the horizontal plane of the pan. Fill it with silicone or caulk – grout will crack out of there.
O, Great and Wise One,
As (your) luck would have it, I have another question about our upstairs bath reno. DH is determined to do much of the work himself (aside from the plumbing and electrical), which puts me in the dubious position of telling him how to do it (as opposed to telling him where to go… although, based on reports of couples and renos, this is a distinct possibility as well).
Our house is 70 years old, and this bath is pretty much a total gut job. Since all the walls & ceiling will be taken down to the studs anyway (including removal of one wall into unused closet space and moving another one back about 15”), our options for materials are open. I’m considering Kerdi board for the approx. 3’x5’ shower, but because the stuff is so new, I can’t find much info on their use other than the Schluter videos. (Well, except that it might be hard to get.)
The problem I’m foreseeing is with the sloped ceiling at the far end of the 5’ shower length. The upstairs ceiling height is 7.5’, and the 2 shower heads will be located at the full-height end of the shower. The slope at the other end begins at approx. the 33” mark, sloping the last 27” down to about a 62” height, where we plan to install a shower bench.
Can the slope be painted, or should we plan to tile it? Also, the info I’ve found so far seems to indicate that Kerdi board has too much deflection for 16”oc studs, unless we use the ¾”, which will affect the thickness of our ceiling (green board?), right? It’s an exterior wall, so maybe drywall first, then cover in either Kerdi membrane or thin Kerdi board? And how to marry the Kerdi with the ceiling at that angle if we tile the slope? Is this what Kerdi-fix is for? Or maybe just tile the whole d
ceiling? WWRD (what would Roger do?)
You do understand that, whatever your answer, I will have more questions? At what point are you going to tell me that we have no business trying to tackle this job ourselves?
Hi Cathy,
You have no business trying to tackle this job yourselves.
j/k
Now that it’s out of the way… Dunno who’s telling you about the deflection problems with 1/2″ kerdi-board but it just isn’t so. The kerdi-board is great stuff and has just as much deflection (or less) as normal drywall with kerdi on it. Once the wall is tiled you’re not gonna move it – guaranteed! So go ahead and use 1/2″ for everything. To tie the walls into untiled planes, like the ceiling or sloped area, just kerdi-fix or silicone the joint (leave a 1/16″ gap). You’ll also want to cut the sloped part back into a miter to fit perfectly against the vertical and horizontal planes. In other words, don’t leave the ends square and have a 1/2″ gap on the sloped transitions.
WWRD? Charge obscene amounts of money for a professional tile installation and make it look spectacular! But Roger is kind of a dick like that.
When I have one of those sloped ceilings I’ll usually tile the entire shower all the way up to the ceiling. I think it looks better and eliminates the goofy looking transition with that end of the shower – everything looks like it belongs in there.
After the redguard do I use thinset to put the tile up. The tile doesn’t adhere to just the redguard does it.
Hi Shaun,
Yes, thinset must be used to adhere the tile to the redgard.
Hi there again… so I’m doing a Kerdi shower and finally got the damn drain in (I used the adaptor drain kit). Ready now to put the drywall up so I can get that fabulous fabric on the walls! How much of a gap do I need to leave between the mud pan and the bottom of the drywall? 1/8″ ok? I think I probably did it back-asswards by not installing it first, but I’m not finding a lot of literature on my specific install. Help?
Gracias!
Hey Stella,
You actually don’t need a gap at all, nothing back there gets wet. The purpose of leaving a gap between your mud deck and wall substrate is to prevent the substrate from wicking up water from the floor – if the floor isn’t wet it’s a non-issue. Put it wherever you want.
Rad! Thanks! Now can I borrow a truck to get said sheetrock home? Doesn’t fit well in my Carolla with a baby seat.
Bungee cords – works on my Geo.
In the process of planning our bath remodel, and since my husband is the one who works to support us in the manner to which we would like to become accustomed, the job of researching the minutiae is left to me.
We will be tiling the shower walls and installing a frameless pivot door. My question is how to tile the door jamb. Since the walls will be roughly 4.5″ deep and the bullnose is 3″, do we tile the entire 4.5″, which allows for only 1.5″ of field tile next to the bullnose, or use the bullnose only? And since the bullnose isn’t totally flat, can the shower door be installed on top of it? FYI, the walls outside the shower will not be tiled. It just seems to me that 1.5″ tile cuts seem awfully narrow and might not be practical or visually pleasing. Oh, and it’s porcelain tile, if that makes a difference.
Stumbled onto your website this morning. You’re a real kick
Hi Cathy, you’re a real kick too!
I usually use two pieces of bullnose for each foot (or however long your bullnose is) and cut them down to half the width of the jamb. In other words, if your jamb is 4.5″ cut each 3″ piece down to 2 1/4″, then install them with the rounded edge on opposite corners so both inside and outside edges have bullnose finish.
Random minutiae: install the tile inside the shower up to the jamb first, then measure the total width. It should be 4.5″ plus the width of the tile. Split that measurement in half for your bullnose cuts.
Thank you, Roger! Your vast expertise is exceeded only by your sheer awesomeness
Hi Roger,
I am a rookie so forgive me if these questions are silly!!!
As I am reading the different sections of your site, more and more quesitons pop up in my head..
Question 1, When you waterproof around the shower, and I assume you have to cut a whole out for the shower head and other plumbing on the waterproof membrane. What do you use around those holes to seal the membrane?
Question 2, Do you need a vapor barrier on the bathroom floor? Or is it okay to put the cementboard on the plywood and off you go?
Thanks a bunch again!!!
PS when you do the niche, do you have to use the bull nose for the sides, or can you cut the regular tile to size and use that? will it look crappy if you do?
Hi Sara,
Silicone around all those pipes and fixtures. You do not need a vapor barrier beneath your floor. You do need thinset beneath your cement board – then off you go.
You don’t have to use the bullnose – you can use whatever you think looks good. If you look at most ceramic tiles you’ll usually fine one edge with consistent color on it. If you simply cut the tile for the niche have that edge as the one that shows – it looks better.
I was hoping to find shower drain installation and recommended shower drains to use on your “How to create a shower floor” page. However, there was no info at all on that page. Please enlighten, this is new construction in a 6’x 4′ shower on slab. In pics from Kerdi’s website, looks like it’s o.k. to use there membrane on the floor. Does this mean no hot mop and would we then need to use Kerdi liner on the floor?
Hey Deborah,
If you are going to use kerdi on your shower floor you need to utilize the kerdi drain. It is made specifically for kerdi and other topical membranes. You are correct – no hot mop. Just fabricate a single-layer mud deck and install the kerdi membrane over it. Schluter’s website has detailed instructions about this type of installation.