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!
Roger,
I am installing 12×12 tile in our shower and I am planning on using DenShield 1/2″ 32″x 60″ sheets.
The guy at Menards (our local home improvement store) said I should still put plastic up between the studs. Will this cause a “mold sandwich” or does this sound ok?
Also do you have a specific silicone and mesh tape you recommend for DenShield?
Thanks and keep up the great work!
I still would like to know what silicone and tape you recommend though. Also while I am thinking of it should I use cement board screws for installing the DenShield?
Thanks again!
Hi Scott,
I usually use GE silicone II. Any alkali-resistant mesh tape will be fine. I use the one from durock, but there are quite a few different ones that work just as well. No need for the cement board screws, you can countersink regular deck screws. If you want to use the backer screws you can, but you do need to use a water-resistant screw like deck screws.
Last Wed. the Ex calls, says a tile fell out n thr shower. Her first question is how to glue it back in. My first question is why did it fall out. I go over to find out. By noon the next day, I had 4 contractor garbage bags full of mush and she had a 6×8 hole in the side of her house. Luckily, the temp. was up to a balmy 40 deg. I swear, if she had leaned against that wall she would have wound up on the sidewalk outside and the neighbors would havs had a show.
So, Thusday I had the wall back up and was ready for the backer board. It just seemed logical to use visqueen,(6 mill) and 1/2 in. cement board. But nooooo, the guy at the lumber yard said can’t use the plastic, the wall had to breath! Breath for crying out loud! And cement board would just mold again. What I needed was this blue board, mold and water resistant wich he just happened to have Ok, what do I know, I’m just a retired airplane driver. So I get it on the wall and figure to put on the new tile the next day with the MASTIC the guy said to use. I kept looking at it and finally said this is BS, it has to have some kind of waterproofing. So I hit the net and found your really neat site. I read all the FAQ’s, downloaded the book, and tomorrow will remove the blue crap and go with the coated board and thinset, as time is short. That’s assuming I can find it in this one horse town in Upper Michigan. If not, back to my original plan.
Really, this is a very good site and you do a wonderfull job of explaining all this. Thanks for your hard work.
Hey Steve,
Thanks for letting me know! If you have any questions at all don’t hesitate to ask. Your original plan is an approved installation method. Vapor in the wall cavity does need to dissipate, but I have yet to see a wall breath.
Your site is truly the best I’ve found to date regarding shower installation. Kudos to you, Roger. I asked Santa for a local tile professional to replace our 48″ fiberglass walk-in shower but all I found was my over-worked middle-aged husband who needs all the help he can get to complete this project. We’re ripping out the one-piece unit and tearing the rest of the small room down to th studs. I’ve poured over all your posts but hope that you won’t mind breaking it down into a brief summary of “this is how I’d do it”. I think it’s studs, plastic membrane either stapled or siliconed to the studs, then…and so on. We watched one of those HGTV bathroom make overs and saw them pour a very sandy concrete mixture directly onto the waterproofed floor. It was the consistency of wet sand, then padded down with the trowel. Is that something you would consider? This is a shower that we use at least twice a day and we don’t ever want to mess with it again. Thanks in advance Roger – you have no idea how much you’ve alredy helped this overwhelmed couple!
I forgot to mention that they were putting river rock on top of the dry-ish sandy concrete mixture. Just wondering how much water this base would absorb and if you had your preference, what type of base would you use that wouldn’t drain our bank account. Thanks again.
Hi Roger, Yes – Tired Mom must be my name, that’s all I hear from the guys when they ask me to participate after a long day at the office “You’re always tired mom.” :o)
We rec’d your email and the pdf is now printed an in a binder to share; what a wonderful holiday gift! We appreciate your time and thoroughness!
Hi Tired Mom (If that IS your real name
)
I’ve watched those shows, mostly for laughs, but I have watched them.
I believe what you are describing them as doing is a poured mud deck for tile. It is the standard way of creating a tiled shower floor BUT they always get their deck mud (the sandy concrete mixture) too wet – waaaaaay too wet – every time. It should be the consistency of sand used for a sand castle. I have a series describing the entire process here: Creating a shower floor for tile. Keep an eye on your email, I’m gonna send you something that may help out a lot more.
EDIT: Umm, your email address doesn’t seem to work for me. Can you send me an email to Roger@FloorElf.com with a working address so I can send you some more help? Thanks.
Roger, what is the proper technique for the water membrane around the tub supply valve and spicket? Do you just cut a hole as close as you can and put the plastic up over it or is there a more sophisticated method with layering the plastic like flashing? Also, would it be better to have one large piece or several smaller pieces layered like the roofing felt? appreciate your time
Hey Jim,
You cut the hole in the barrier the same size as the hole in the backerboard and silicone the barrier to the back of the backerboard. This way when water runs down the membrane it will hit the silicone and run around the hole. With the cover on the control and escutcheons water will not penetrate the wall through the front of the hole, you just need to be concerned about water running down the membrane.
I am gutting and restoring a bathroom and will be tiling surrounding a tub. I like the idea of a membrane, but thought that one of the reasons for the backerboard is that it has more strength compared to sheetrock. Or do you just recommend a thicker sheetrock like 5/8″? Thanks.
Hi CM,
I think you’re confusing two different things – the membrane and the substrate. Unless you are using kerdi or one of the faced boards like kerdi-board, wedi, or denshield, you should have cement backerboard on your wall. The ONLY time drywall (sheetrock) is acceptable inside a shower is when using schluter kerdi. That’s it – the only time.
Even when using cement backerboard you need a membrane of some sort. Either a moisture barrier behind it or a topical membrane such as redgard on the front of it. You always need a membrane of some sort in your shower – it is the only way it is waterproofed.
Tile wall mystery: Old shower walls were totally gutted and new “pink styrofoam” (unknown name) wall board installed on all three sides. White subway tile installed, but the end result is an uneven/unlevel job with waves and dips, and sharp edges of tile exposed when you run your hand over the surface. What happened? I expected that the new walls would provide a totally smooth surface upon which to install the tile. Also, the curb has exposed cut edges on the corners; shouldn’t bullnose have been used here? And, the wall tile just abruptly ends at the floor; shouldn’t cove base have been used to finish it off? I was not present at the time of the actual tile install…and cannot get an answer from the installers. Would appreciate your thoughts! Thank you!
Hi Marcy,
I’m not sure what ‘pink styrofoam’ product you would be talking about. I’m not aware of any such product approved as a tile substrate. The only products which would be similar would be wedi, which is blue, or kerdi-board, which is orange. As far as the tile itself it does sound as if it is a poor installation. Bullnose is normally used for tile and there should be no lippage (the uneven tiles), or exposed cut edges. All of those are indicative of a sub-par installation which makes me leery of the product used as your substrate. Cove base at the bottom is more of a geographical thing – it’s rarely used around my part of the country, I normally just run the wall tile straight to the floor.
Thank you so much for all the help you provide, this has been a learning experience reading everything you’ve written over the past few days. I have a small bathroom I’m remodeling in an old house. It’s an upstairs bathroom that I plan on tiling the shower walls and the floor. A total of 78 square feet. The upstairs floor joyces are 2×10 on 16″ centers and 3/4″ ply wood over that……THEN they have the bathroom floor raised above that with 2×6’s on top of that. (it was obviously an after thought and they raised the floor to accomodate the plumbing) I have redone the raised floor joyces 2×6″s on 12″ centers and blocked them all every 12″ as well, I’ve then installed 1-1/8″ sturdy floor T&G ply wood over that. It is solid and has very littel deflection with my 300 lb ass stomping on it, now there is a smidge but not much. Everything has been nailed/screwed together thoroughly and now I’m ready to lay the substrate for my tile. So this brings me to the questions. Apparently I’ve never done tile the proper way, (according to everything you’ve taught me) and this time I’m gonna try…..LOL. I like the idea of using Densguard on the shower walls for expense and ease of installation. To clarify, do I screw it up horizontally or vertically and then caulk between sheets, where board meets lip on tub and around the single handle fixture opening…correct? Now when I lay the tiles, (12×12 Dal floor tile) what should I use for thinset…something with polymer to help with the potential for deflection/movement in the upstairs of this old house……or what are my options? Also what grout do yu recommend and is the epoxy version a more solid option for me?
Ok now on to the floor…..can I lay the densguard on the floor OVER a layer of thinset and have a solid, waterproof substrate ? (caulking the seems and taping them same with the shower walls I assume) If this is ok what thinset should I use under densguard and between densguard & tile and what grout…..keep in mind this is an older house though I’ve over built the floor support it’ll still have movement I’m certain. Thank you so much for all your help and humor it’s hugely appreciated!
Hi Mike,
You can install the denshield (densguard and denshield are two different products – you want denshield) vertically or horizontally. Once you get one sheet installed, silicone the side of it and install the next right against it. And yes, everything else is siliconed as well. You can use denshield on the floor as well, in the same manner except with thinset beneath it. It doesn’t matter much which thinset you use beneath it – it is only there for support, not to adhere anything. For the tile installation you do want a modified thinset. Versabond from Home Depot or Mapei Ultraflex II from Lowes are two good ones.
Epoxy grout is always better than regular grout – but it is expensive. I prefer Laticrete specratlock, it’s fairly easy to work with and is a very, very good grout.
I am hiring a tile installer becasue m previous tile installations never turned out as besutiful as i would like as this is my master bath. This guy is also going to install my mud pan and liner. I am going to preparethe walls. I read your manual/ebook, and i wanted our advice. I obviously don;t want any problems with water, but i also really don’t want to have to worry about this for years to come. Between using 6 mil plastic and 1/2″ hardi board as option 1 or installing denssheild as option 2, which do you believe is the better option? I have also considered doing hardi-board and installing redgard over that and the floor once the pan is built… Any opinions to share? If it helps one option or another, 2 walls of this shower are exterior and it is a 6′ X 5′ shower.
Hey Vince,
The backerboard and redgard is a better option – but if there is a liner in your shower floor only paint it onto the floor about three inches out onto the floor. Do not go over the entire floor. My second option would be the denshield, properly sealed on the seams and screw holes of course.
Roger, I’m installing wall tile in a tile shower (no tub): I have installed vapor barrier against the studs, then installed cement backer board over the vapor barrier. I now have a few questions:
1. How should I seal the seams between the cement boards? Should I be using fiberglass tape and underlayment? Or should I use silicone in the cement board seams?
2. Should I use Silicone sealer around the base of the walls where it meets with the shower floor?
3. Once all the seams are sealed, should I Red Gard the entire face of the cement Backerboard before tiling?
4. Should I use Acrylic Mastic or Thinset mortar to adhere the tile to the backerboard?
thanks, Jay
Hi Jay,
1. You should use alkali-resistent fiberglass mesh tape and thinset to seal the seams.
2. No, that will not allow water from the vapor barrier to get into the drain behind the tile.
3. No, you want either a vapor barrier or a topical membrane (redgard) – never both.
4. Thinset mortar to install your tile to the substrates.
Roger
Contemplating tiling my shower ceiling. The shower ceiling is separated from the rest of the bathroom by a 1 foot ‘wall’ and traps moisture. Can you use Kerdi on the ceiling?
Thanks
Hi Fubar,
Yes, I always use kerdi on every ceiling I tile. No problem at all. If your user name is any indication of your shower tile perhaps you should begin again, eh?
Roger, I have a home in south Florida and I ripped out the old tub and tile and have installed the new tub and I am ready to start the tile. One wall is an exterior CMU wall, the other two are interior wood stud walls. I was going to install Aquabar B to the studs and then a cement board over that and then tile. Is this a good system or would you recommend against it? I have purchased the materials but could easily return them. I had also planned to run the Aquabar B over the lip of the tub and stop the cement board at the lip so it does not bow out. I was also planning to leave about an 1/8″ gap where the cement board meets the green board that is on the remainder of the bathroom walls and fill with silicon. I would then allow my tile to just cover this silicon filled gap. Any suggestions would be greatly appreciated. I really enjoy your site!
Thanks,
Scott
Hey Scott,
Aquabar B is good stuff, combined with cement board it will be just fine for your shower. Make sure after you run the aquabar over the tub lip that you silicone the back of it to the tub lip to prevent water from getting up behind it. Rather than silicone between the backer and greenboard you should use fiber mesh tape and thinset. This will lock them together so they don’t move independently. Silicone will allow them to move separately which may lead to problems at the edge of your tile installation.
Thanks Roger, I took a break to work on my other 25 home improvement projects and now I am back on the shower. I put up my Aquabar B and started putting up my cement board when it occured to me I would like to add a recessed niche for shampoo also. Can I just cut my Auqabar B in a X and fold it back into some wood blocking I will add into the wall and then just add cement board and fill the seams with my thinset and fiber mesh tape? I think I read somewhere that I should not use a water proofing product on the outside if I have installed a moisture barrier on the inside?
Hey Scott,
You only have 25 goin’ on??? Trade ‘ya.
If you are using a membrane behind the entire installation you do not want a membrane over the entire face of the substrate. It is always best to go ahead and use a liquid or fabric topical membrane for your niche. Yes, cut an X in the aquabar and fold it back into the wall, install your niche, and use something like kerdi or redgard inside the niche and about two inches outside around it.
Hi Roger,
I have started a project to replace a tub area with a tiled shower using the Kerdi system. I understand the importance of waterproofing the floor and walls, but what about the ceiling? I have purchased a new ceiling light that is UL approved for wet locations but if I put the Kerdi system on the ceiling how do you seal around the electrical ceiling box?
Thanks in advance for your response and the great website.
Lloyd
Hey Lloyd,
You can use kerdi-fix or regular 100% silicone to seal around the ceiling box, as well as any shower controls.
Hey Lloyd,
You can use kerdi-fix or regular 100% silicone to seal around the ceiling box, as well as any shower controls.
I noticed on here, where you stated not to use greenboard. I got a question I hope you can help with. I already installed greenboard on my shower walls, but I plan on wrapping that with vapor barrier and then installing the cement board. Would I be okay then. I’m trying to avoid from removing the greenboard, but if I need to, now is the time.
Hey Wes,
IF your walls end at corners and IF you are tiling all the way to those corners and IF you are tiling all the way to the ceiling and IF you get your moisture barrier installed perfectly and IF you ARE NOT having an inspection done by the city (greenboard is currently against code by most building standards) – then it won’t be a problem. IF any of those things are not true you will either end up with a bump-out on the wall around your shower (the tiled portion sticks out further than any other wall it meets) or you will end up with wet greenboard – which WILL grow mold. Completely up to you.
Am installing new tile over new cement board coated with Redgard, while searching your site for an answer as to how to handle (waterproof) the gap between the cement board and the lip of the existing tub I found the below answer. How will the same result be achieved using Redgard?
Roger November 9, 2011 at 9:41 pm
Yes, tile is fine in those areas without thinset behind them. With kerdi you would run the kerdi all the way down to the tub rail and silicone the back of it to the tub lip to prevent any water from getting behind the kerdi.
I will keep reading, perhaps discovering the answer in another comment.
Thanks, Ron
Hi Ron,
You would silicone the gap between the tub and backer and paint the redgard right over that once cured.
I believe ill be re tiling, does the moisture barrier on insulation against the studs, behind the concrete backer count as “better than nothing”? 3 shower walls(1 exterior) were insulated from inside, with paper barrier carefully stapled to studs. Augggh just typing it out I feel so stupid for not vertigo a book. I’m retiling fer sure huh?
Hi Uh Oh (If that is your real name
)
Yes, it’s better than nothing – especially if you already have your tile installed. Just keep a very close eye on the installation and make sure it doesn’t begin to get squishy anywhere.
PUTTING IN A NEW SHOWER….USING A KOHLER FIBERGLASS BASE>>>>NONE OF YOU MENTIONED A BACKER”GREEN BOARD” FOR THE MEMBRANE AND HARDI/BOARD OVER THAT>>>>>>I’M DEALING WITH H/DEPOT ONLY>>>>>.WILL THE H/BOARD LEAVE ME THE CHOICE OF MATERIAL TO USE ??? LEXON ,RECYCLED GRANITE,TILE I’M UP IN THE AIR AS TO WHAT I MIGHT USE>>>I WENT CRAZY WITH WINDOWS IN THE SHOWER 2X4 ON THE SIDE AND 2X3 AT THE FAR END , WANTED LOTS OF LIGHT>>>NO SKYLIGHT.. DROPED CEILING TO 7′ X 6″ PLANNING ON HARDI BOARDING THE CEILING++SOUNDS LIKE I’LL HAVE TO USE PLASTIC ON THAT…
Hey Paul,
Green board should be absolutely nowhere near a shower at all. It is no longer approved for wet areas. The plastic just goes directly to the studs and the backerboard over that.
Hi Roger,
We are tiling a shower and want to get your opinion on using redguard. The drywallers’ used Dens Armour Plus … here is what the site says about it … DensArmor Plus® High-Performance Interior Panel is a highly mold-resistant interior gypsum wallboard. DensArmor Plus mold-resistant interior drywall panels carry a 12-Month Weather Exposure Limited Warranty. I just want to clarify that we do not need to redguard over it before tiling, thanks for your time.
Hi Devin,
That is not correct. You DO need to waterproof Dens Armour, only denshield is approved for showers. DensArmor Plus does not have a water-stopping acrylic coating, denshield does. DensArmor Plus is intended mainly as a backing unit for exterior facades such as stone and brick veneer, not for wet areas such as showers. You will need to waterproof that in some manner.
Roger,
I want use to Kerdi but I have a concern about the curb. I may use a frameless glass door and glass panel to enter the shower. I’m worried the weight of the glass door/glass panel on the curb may cause it to crack. Is this a concern? Should the curb be built up with another more firm material if I’m considering placing the heavy glass on top of it?
Thanks,
Eric
Hey Eric,
The kerdi is simply a thin membrane material which will be placed over your built curb. The amount of weight it will support depends entirely on the curb you build for your shower and nothing at all to do with the kerdi itself. If you are talking about the kerdi curb (the styrofoam one) it will support the entire weight of your glass without a problem – really.
First, I want to say that you do great work helping us DIYer’s, thanks a bunch. Now for my question… I have ripped out my old tub surround and am now ready to start rebuilding. I was planning on Durock, with a poly sheet behind for waterproofing. But now I’ve read your niches blog and want to build that, but can’t figure out how to water proof it cuz I can’t use the poly sheet, right? Also, I have a window that I haven’t been able to figure out how to waterproof or tile. It’s in the CMU outer wall and it was just mortared to the concrete, I’m thinking that’s not right, but don’t know what to do. HELP PLEASE!!! Thanks so much!
Hi Caryn,
It can be done with the poly, you’ll just cut the poly in the same shape and put it in there before you place the backer over it. Use silicone rather than thinset to stick everything together. You can also install your walls, cut out your opening and silicone your poly to the back of your backerboard and use a liquid membrane such as redgard inside the niche to waterproof it. The best option for your window would likely be redgard as well.
I’ve been in a lot of forums and read a ton of posts in the last few years and this one has probably been the only, “one stop shop” so to speak, that I’ve been to. I love the fact that you have a good sense of humor about it. Ive been doing every aspect of home remodeling now for about 7 years so I still come across new problems and jobs that I’ve never experienced or done. I’m constantly on my iPhone looking up proper methods or solutions to common problems and most of the time I’m already frustrated cuz I’m only looking it up cuz I’ve already done something wrong and realized it isn’t going to work. Theres also an app for the iphone thats been very helpful. Its called CT Forum. (hope thats ok? I dont work for them or owe them any $ either! It’s just been very helpful :-)) not only has this site has been VERY helpful but It’s nice to read a few things that make you laugh. It definately makes the day a little brighter! Thanks
Thanks Brian! Glad I could help.
I have tiled a number of bathrooms in my old house “old school” with 15lb felt, cement board, thinset, tile, yadda yadda yadda (getting the yadda to look good is difficult)
I now have a NEW house which needs the 1972 lovely blue bathroom erased from the earth.
I am loving this Kerdi and plan to use it. However the preferred backer is DRYWALL ?!?!?!
I can follow instruction (and I will) but the old school in me wants to put up 15 lb felt, cement board, and THEN Kerdi.
Why is the preferred back board for Kerdi drywall? Is it just because it is cheaper and easier to work with, or is there a performance reason as well?
Thanks for an awsome site by the way
-dave
Hey Dave,
No reason at all not to use cement backerboard if you’re more comfortable with it. DO NOT place the felt behind it – it will trap moisture in the wall substrate. Make sure to wet down the backer before installing the kerdi, backerboard sucks moisture out of thinset prematurely. I think they state drywall simply to cater more toward the DIY market, most homeowners don’t like working with backers. Either one works just as well.
Thanks for the answer. One more follow up. When using felt paper and cememt board in a tub enclosure, I would run the felt down OVER the lip of the tub, then stop the cement board just before the lip (to pervent a hump). I would then pack a bit of thinset in that space when placing the tile, still leaving 1/8″ or so to run a bead of silicone.
What is the procedure for the edge of the tub when using Kerdi? The way I used to do it, the felt paper would prevent any water that wicked up into the cement board from getting to the studs. With Kerdi, there is no barrier against the studs, so you have to seal that raw edge of the cement board or sheet rock. Do I just use silicone caulk? Somtimes that lip can be pretty big. Is it OK to let the first row of tile overhang that much with no real support behind them?
Thanks again.
-dave
Yes, tile is fine in those areas without thinset behind them. With kerdi you would run the kerdi all the way down to the tub rail and silicone the back of it to the tub lip to prevent any water from getting behind the kerdi.
Hey Roger,
New to the site….very impressed! After looking over your site(for over two hrs) I have a few ?’s. 1. I remodeled a bathroom shower using the moisture barrier drywall (the blue sided stuff) and did not usea moisture barrier behind it…if and when could I expect problems. 2. Can roofing felt be used as a moisture barrier? 3. Do I have to prep a concrete basement floor before I tile over it?
Thanks!
Hey Brian,
1. That depends on what type of tile, what type of grout, how often your shower is used, the flow rate of your shower head, etc… In other words, it’s a question that can’t really be answered.
Sorry. It may be fine for as long as you want, it just isn’t guaranteed.
2. Yes, roofing felt or tar paper can be used as a moisture barrier. It actually works better than plastic. Weird, right?
3. You don’t HAVE to. It depends on what shape your concrete is in. Splash a few drops of water on it and see if the concrete soaks it up. If it does you’re good to go. If it beads up and sits on the surface you need to mechanically or chemically scarify the surface so the thinset will grab onto it. And while you CAN tile directly to concrete, it is always best to have a membrane such as ditra over it.
Hi Roger,
First off, what a fantastic website, I really appreciate all the time and effort you’ve put into it, with absolutely no expectation of getting compensated for it. I would, however, love to email you some beer if that ever becomes possible.
Ok, anyways, I didn’t just comment to say thank you…but that would have been nice of me…I do have a question to ask, that I expect is a very dumb one.
What is the difference between “regular drywall” and “plain drywall”?
No, it’s not a riddle, it’s actually a question. The reason I ask is because I think I want to use that Kerdi membrane, which you type can be installed over “regular drywall” but then in a separate paragraph you say not to use “plain drywall”. I am expecting the answer will be something like “it’s the same thing (you jack ass), I’m just typing that you should never use plain drywall without the Kerdi on top.”
Thanks
Hi Andrew,
You answered your own question. But I’ll take the emailed beer anyway.
That was simply a caution not to install tile directly onto the drywall without a waterproofing membrane over it. Sadly it doesn’t usually work – people do it anyway.
Excellent, thanks for the prompt reply!
Do you have a “donate” option anywhere on the site? Maybe I could donate enough to get you that beer after all
Nope, I do it all for free – I’m just super cool like that.
I ask anyone that wants to donate to make a donation to Homes For Our Troops, one of my very favorite charities. Thanks Andrew!
Super cool indeed!
Thanks Roger
Where does the waterproofing stop? Do you roll your Aqua Ban on the floor before you tile? Do you go 6 to 8 inches up the walls of the entire bathroom? Many walls are next to closets or bedrooms. Its amazing where kids can track water. I have a closet that is connected to the bathroom wall. The sheet rock is crumbling off at the floor area due to moisture from the bathrrom.
Hey Michele,
I will usually run the waterproofing about three inches out onto the floor outside the shower. However, you can waterproof everything that will be covered with tile if you want to. Entirely up to you. If you do go up the walls around the perimeter install a bead of silicone around there first, then paint the waterproofing onto it as well.
We are remodeling our master bathroom, and are ready to start tiling the shower. As we were dry fitting the tiles we realized the Durock is not completely flat, some of the tiles will not lay flat, we are wondering if the mortar be enough to level the tiles out or do we need to sand the Durock or something? Thanks
As long as the variation is less than about 1/4″ then thinset should be fine to get it all flat.