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!
Hi, my husband is a retired mason. We bought a house that need updating.he tore out our master bath and put new insulation, vapor barrier (plastic 4 ml) and tiled shower walls but he put that black plastic for the base of shower and concrete 6″ deep and then put small river rock with thin set. And water leaks in the back corner behind shower. The black plastic goes up the wall 6″ under the tile/thin set. The slope in the shower base to the drain is 1/4″. What did we do wrong? How can we fix this?
Hi Ginny,
It could be a number of things. Start here and read the proper steps and see which ones were missed or not done: Creating a shower floor for tile
Hi Roger,
Once again thanks for the wealth of information you provide to guys like myself!!
I’ll be doing a 36″ square shower in our basement bathroom with a preformed acrylic base (single threshold), and wanted to know if there should be any waterproofing of the plywood floor? I’ve still got some Redgard left from the previous project in our other bathroom.
Regards,
Jeff in SK
Hi Jeff,
You have a plywood floor in your basement?
No matter. If you mean under the base then no, no reason to. If you mean the bathroom floor itself there’s no real reason to, but you can if you want to.
Ok, I have been loving Kerdi-board for installation but by the time I kerdi-band (is that even a verb?) all the screws that hold the board to the wall and kerdi-band the seams I don’t feel like I saved any time. Have you ever tried using kerdi-board and using redguard for the screws and corners?
Hi Chris,
Kerdi-band is a verb.
I use hydroban rather than kerdi-band in my showers. Redgard will work as well. It is SO MUCH faster, easier and better.
Does the use of laticrete Hydro ban complicate repairs? I’m concerned that replacement of tile and or grout would damage the water barrier? Is laticrete hydro ban simply reapplied in such circumstances?
Hi Kathy,
Yes, it does to an extent. You need to ensure that when you replace the hydroban you get a good seal between the existing hydroban and the new. The easiest way is to cut out all the way through the hydroban against the tile you’re removing. That way when you remove it you should have a grout line’s width of existing hydroban left on the wall to tie in with the new layer.
Awesome – precise – answer. I can do that. That might make a good tip to add to the book.
I’m considering a shower floor of sliced pebbles. Obviously, this means a lot more grout than using a 2″ (porcelain) tile. I’ll have the hydroban, and a bit more slope than the 1/4″ per ft required. But ultimately, it seems unlikely that small puddles can’t be completely avoided. If the mortar bed is graded correctly will I have a problem from likely unevenness in grout and/or sliced pebbles? Or does potential repair work strongly indicate a preference for the 2″ tile?
Provided the floor is sloped correctly you won’t have any problems with flat top pebbles at all.
Roger,
I recently installed my first Schluter Kerdi shower system complete with shower pan. I installed a mosaic tile consisting of 2X2, 2X1 and 1X1 glass and porcelain tiles on the shower floor. It was different from any mosaic that I had worked with in that it didn’t have a mesh backing, but rather the front of the tile was faced with paper. (Which was removed by wetting it with a sponge after about 30 minutes.) I set the tile in to a good bed of non-modified thinset. All was good until I went to clean up some extra thinset a few days later and had a tile pop loose. Then I went picking around and found several loose tiles which I took up and reset with modified thinset onto the layer of non-modified that remained. I haven’t been back yet to check on things but I’m a bit nervous. Do you have any thoughts on this? Why did my tiles come loose? Do you think I need to be nervous about the remaining tile? Do I need to pull up the tile? Was it the wrong type of tile to use with Non-modified? Thanks for any advice you can give.
Brad
Hi Brad,
Mosaics with glass should not be installed on a floor, and glass should not be installed with unmodified thinset. The good news is that if they aren’t loose now, they likely won’t be loose in the future. So if you get all the loose ones reinstalled and grout you should be fine.
The kerdi board does seem very expensive. Would this work just as well for a shower? I am using a pre made base.
http://www.menards.com/main/building-materials/drywall/cement-board/fin-pan-propanel-1-2-x-3-x-5-backer-board/p-1698651-c-5705.htm
Or should I just use wonderboard or concert board? I want to make sure I am using the correct method before ordering any books from you. Thx.
Hi Jeff,
The finpan boards work very well. Make sure you follow the installation instructions and get them installed correctly, but they work just fine.
Thanks for the quick response. So the book ‘Topically faced shower walls around a tub or pre-formed base’ would be the one I need, Correct? I have laid quite a bit floor tile but I do not want to make a mistake with the prep for my shower. Your site is an excellent resource. Thanks for sharing.
Yes, that would be the one.
You da man, Roger!
I will forego the kerdi, as well as, the Mapei Aquadefense and simply tape the seams with a fiberglass cement board tape. Then, apply thinset and tile and grout.
I’m buying the New Belgium Sunshine Wheat if I ever make it to Fort Collins…
Thanks again for sharing your knowledge with this first timer…
Good beer!
Roger,
In preparing to tile a shower my plan was to install a vapor barrier, hang backer board, then Mapei Aquadefense, then mortar and tile. After reading your instructions I understand a moisture barrier on both sides of the cement board is no good. I had already hung the vapor barrier (4 mil) and cement board. So, my new plan is to install Kerdi on the cement board seams/corners. But, on the Kerdi website, it does not recommend a modified thinset (I just bought Mapei Ultraflex 2 which is modified but haven’t opened it). So, in looking at Kerabond (Mapei) that would be recommended it appears it is a dry-set. Not thinset. Is this Okay? Am I in trouble anyway in using Kerdi with the vapor barrier up behind the cement board?
Or, can I just use mesh tape on the backer board seams and not worry about the Kerdi? Some corners have a 1/4″ gap where the cement board doesn’t perfectly come together.
Or, would it be better to tear the 4 mil vapor barrier down (I have access to it from other side of wall) and apply the Mapei aquadefense to cement board and fill in the corners with a generous amount?
Your knowledge and expertise is highly appreciated,
Brad
Hi Brad,
Dry set mortar is just a technical term for unmodified thinset. You can also use modified thinset – just don’t tell ’em I told you that.
You can also forego the kerdi and just use mesh tape and thinset, the vapor barrier is just fine. Water will get through backer as quickly as it will thinset, so kerdi on the seams really doesn’t do anything. Backerboard is not waterproof, just water stable. Right now your shower is waterproof, just tape the seams, it’ll be just fine.
Hi Rodger,
I was wondering about waterproofing around my cutout fixtures. My plumber is coming back and only has rough in pipes sticking out right now. Once he puts the permanent pipe on and handle do I need to caulk and or Hydroban right up to that pipe before he puts the final covers on? I’m assuming so otherwise water could get in there and then why did I spend all that time waterproofing everything? I don’t think many people do what I’m talking about. Any thoughts?
Hi Hogan,
You can hydroban right up to them, and actually onto them. Or you can just do this.
Hi Roger,
I’m confused on a few things. I’ve read your waterproofing e-book and also your linear tile-in drain article.
1) Your waterproofing e-book implies that Kerdi is significantly more expensive for shower walls than CBU and HydroBan, but in pricing materials for a 6’6″ square shower area, it seems like 5G of HydroBan ($300) plus 12 3×5 sheets of CBU ($13/ea plus screws and mesh tape ~$175) totals $475 whereas 200sf of Kerdi ($300) plus Band ($75) plus unmodified thinset, plus Kerdi fix sealant ($50) plus drywall ($50) — but still the Kerdi system seems roughly the same cost as Hydroban. Am I missing something ?
2) I’ve seen these “tile-able” shower bases you mention in the e-book, and they are actually much more expensive that the same size acrylic bases. In your linear drain article you applied HydroBan to the metal drain piece to make it a tile-able surface. Wouldn’t the same thing work for an acrylic shower base ? Would that make a $200 acrylic base plus $20 of HydroBan the equivalent of a $600 “tile-able” base ?
Hi Kirk,
1. Nope, you’re not missing anything. I wrote that manual, as well as most liquid waterproofing posts here, assuming redgard since it is available at big box stores and seems to be the one most people have access to. 5 gallons of redgard is about $120, 5 gallons of hydroban is about $300. All said redgard is about $200 cheaper per system than hydroban (on average). Hydroban and kerdi showers are about the same.
2. I honestly don’t know if laticrete approves acrylic as a suitable substrate. Whether they do or not – flexure in the acrylic base could be extremely problematic. A mud base would be the equivalent of a tilable base for about $50.
Roger,
1) I notice you seem to use HydroBan more than RedGard, and I suspect that means you think it is a better product ?
2) Yes a mud base seems cheap and easy (to a professional like you), but then the HydroBan becomes critical to prevent leaks from the most critical water-holding element in the shower — instead of just giving tile something to stick to. And you then need to spend $100 on a topical drain rather than the cheaper $12 drain that would fit the acrylic base, right ? I was hoping the newer acrylic bases with the high-density styrene backing wouldn’t flex much. Is that not true ? I had always assumed I was going to have to do a mud base because the joist (actually engineered truss floor system) spacing kept interfering with the drain placement of available bases. I was kind of excited to find rearranging fixtures meant some bases with drains would fit … but maybe give me the option to tile over it in future if the acrylic starts to look cheap. Just chicken about creating a waterproof pan/curb, I guess.
1. Yes, I do think it’s a better product. I like the workability of it over redgard, the time between coats is better and it’s laticrete, which means I have complete support. I always have it with me for a number of things, not just waterproofing. It’s an extremely handy product.
2. You can actually do it with a regular three-piece drain – just google ‘divot method’. It’s also included in my liquid waterproofing manual.
Roger,
That divot method seems time consuming and error prone. I can see why the makers can get ~$100 for topical drains.
Hi Roger,
I’m in the process of completing a new below grade basement bathroom with tiled shower and have been researching Schluter Kerdi as a waterproofing membrane.
As per the Schluter Kerdi install guide (although from what I’ve read you still don’t recommend it) I have used drywall for my shower walls and have a slopped concrete mortar bed for my base. Surrounding my mortar base I have used Cement Board which rises about 4” above the base before the drywall.
Tilemasters Canada sold me the Kerdi membrane and recommended that I use Kiesel Servoflex-Trio-SuperTec for thin set to bond the Kerdi to the drywall and eventually tile to Kerdi. Tilemasters is listed as a dealer on the Schulter website for my area so I’ve taken what they recommend as correct information.
Researching the Kiesel Servoflex-Trio-SuperTec I’ve realized that this is a modified thin set and as per Schluter should not be used. I’ve contacted Schluter directly to find out why a dealer would recommend a modified thin set and how this could potentially impact the Schluter Kerdi warranty. After being place on hold for a few minutes I was told that Schulter will still honour the Waterproof Warranty aspect of Kerdi and that Kiesel will Warranty the adhesion of their thin set in this application.
Having limited experience with this sort of work I was hoping for some insight from anyone who may have used or heard of the Kiesel Servoflex-Trio-SuperTec being used with Kerdi.
Thanks.
Kiesel Servoflex-Trio-SuperTec Info Sheet:
http://en.kiesel.com/fliesenkleber1.html?&no_cache=1&user_crikieselproducts_pi1%5BshowUid%5D=1387&user_crikieselproducts_pi1%5Bcuid%5D=1388&cHash=38edbd6eca9c07cd3f69670332cccd4e
Hi Scott,
Schluter requires unmodified thinset to be used with their membranes in the States. Schluter actually accepts modified thinset with their membranes in Europe and a few other locations, and have for years. It looks like they are also beginning to phase it in with locations in Canada. I have never heard of that particular thinset, but if they accept it then you’re good to go with it.
As an aside: I regularly use modified thinset with schluter products with at least 60% of my installations. I believe they are changing their view because competitors are supplying membranes which accept modified thinsets.
Hi Roger,
My husband and I are remodeling our bathroom and have been reading your tips for successful waterproofing. Our house was built in 1927 and has plaster walls in the bathroom. The wall around the tub is some type of rock like material bound to metal mesh with plaster over that. We are going to tile that area and are thinking a liquid membrane seems to be the way to go if we can apply it directly over that surface. Your advice would be greatly appreciated.
Thanks,
Eugenia
Hi Eugenia,
That is likely a regular mud wall in your shower, which is STILL the best substrate for a shower wall. If you can rough up that plaster (or, ideally, remove the plaster back to the mud) you can go right over it with redgard then tile.
So let’s say I use Hardiebacker on the walls. What happens in the future when my wife wants to remodel again? The HB will be screwed onto the studs, and the screws will be completely covered with mortar and tiles. How the heck will I remove the tiles and Hardiebacker? I’m already getting nervous about my kitchen floor – porcelain tiles over HB. I think I will have to move when she says it’s time to remodel the kitchen.
Never worry about how to get it out when you install tile. Hammers and crowbars make quick work of nearly anything, as does a Bosch bulldog. It’s hard work, but it comes out. I tear them out every week. Worry about building it to last, and make her pick out tile she’ll be happy with for a while.
Got the DS up today and thinking over the use of AD. Really, if there is a problem with the install I would be more concerned about getting it fixed than trying to get someone to pay for it; and the time associated with doing that.
My only concern is if I’m compromising something by not using thinset. Got any thoughts on that?
I just read where you weren’t using mesh and thinset – you need to do that. It has nothing at all to do with waterproofing, it’s to tie the individual boards together to create a single plane on each wall.
I was going to tie the boards together via mesh and AD instead.
The AD won’t do the same thing, not even close. It needs to be taped and mudded.
So you were thinking AD over the mud as waterproofing.
Ed, you’ve got several things going on and I think it may be confusing the outcome. First lets deal with the board itself, it needs to be screwed to the studs and all seams and changes of plane need to be taped and mudded. If you are using AD tape and mud the seams first, then do AD for waterproofing. If you are not using AD use silicone at all seams to waterproof them, then tape and mud.
The AD is not required, it simply takes the place of silicone for waterproofing purposes at seams, changes of plane and the heads of the screws. The waterproofing of the boards and the taping and mudding of the boards have nothing to do with one another. The order of installation in regards to the waterproofing depends on which waterproofing method you choose as stated above.
Thanks, Fully understand and we are in agreement. I just saw a video where the guy just used AD with the mesh tape but I’ll follow GP instructions and save on the AD.
Roger,
DensShield is up and I’ve siliconed the corners and cutout edges. Now we are down to the screw heads. GP mentions nothing about this specifically but does mention to silicone all penetrations of which I think the screws would be in that category.
Given that thinset does not stick to silicone… is there a chance that the tile adhesion is compromised by putting silicone on the screw heads? I would think not even if the thinset does not hold where the siliconed screw heads are, that will only reduce the potential contact area by a few percentage points.
Can’t see how just a little smear of silicone with the tip of my figure could hurt.
thanks,
The screws are exactly what they are talking about when the say penetrations. Use silicone over them. The area affected by lack of thinset bonding is negligible.
Done and green mesh tape embedded in Thinset on the DS and in drywall compound on the adjoining water resistant drywall sheets not in the shower area.
All seems good so far. Now onto preparation for tiling. So far I’m keen to use epoxy grout and heard that Spectralok Pro is very good and is easier than other epoxy grouts to use. Gotta find a local distributor for it first.
And still need to decide on exactly the grout width that I need to use. Someone mentioned to measure the tiles and see what the variation is in length (i’m using 12 x 24 tiles) across a few of the tiles. Then take that difference and multiply by 3 to get a minimum width that will hid this variation.
Also still have not exactly finalized the tile layout pattern. With this size tile and potential bowing of the tiles in the middle that no more than a 33% overlap in a brick type pattern should be used. I’ll check the bowing later on to see if I can go 50% overlap. Tiles are 5/16″ and 3/8″ thick so I hope that helps reduce the bowing affect.
In the meantime, finalize feathering out drywall compound around shower, paint ceiling and walls, install Ditra.
Should I tile walls first or last?
I normally prefer doing the floor then the walls. You can do it either way, though, doesn’t make a difference.
Hi Roger,
Got the floor levelled with SLC and installed acrylic shower base and now am going to install DensShield around shower stall.
I’ve read the DS install instructions but they are not good with waterproofing. So here’s what I plan to do:
1. Coat all edges and cutouts(cut and uncut) with a coat of Mapei Aqua Defense to prevent moisture transfer to the inside of the DS.
2. Run a bead of silicone between all panels to prevent transfer of water to behind panel. Silicone bead at edges could do most of #1 but there is a chance that the bead leaves a gap between the front waterproof panel of the DS and the internals.
3. Apply AD to the edges and corner joints and embed some fiberglass tape. This will waterproof the corners and is a bit of overkill at those connections but does then keep the thinset off of the silicone bead. Thinset and silicone don’t adhere well but Thinset and AD do.
4. Coat all screw heads with AD.
I think this should do great to waterproof. The only item I am not doing from GP installation is embed the fiberglass mesh in thinset. Thinset will not prevent water from getting to the edges of the DS.
Do you see any reason for me not to do what I have planned or do you have any suggestions?
thanks,
Hi Ed,
Nope, nothing further from me. Sounds like a solid plan. When I screw the DS up I normally place a dab of silicone on the board, then drive the screw right through it. This seals the penetration as is goes in. With AD it’s not really necessary, but that’s how I do it.
Thanks Roger, AD not recommended by GP approved list. I’ll call on Monday to see if it is an acceptable alternative. Any other waterproofing membrane you might recommend?
Aquadefense is just fine. You’ll NEVER find a manufacturer who recommends a product made by another company for use with theirs. Ever.
Yes they do…see below.
DensShield® Tile Backer
Any installation recommendations of other
manufacturers using DensShield Tile Backer as a
component must be in accordance with the installation
instructions contained in this brochure. Direct
questions to the Georgia-Pacific Gypsum Technical
Hotline at 1-800-225-6119. Or visit our website at
http://www.gpgypsum.com. Georgia-Pacific Gypsum is not
responsible or liable for improper DensShield Tile
Backer application.
Finishing Materials* Manufacturer
Genesis® DM; DS174 Dryvit® Systems, Inc (1.800.556.7752)
Sto Flexyl,TM Sto Primer Sto Corp. (1.800.221.2397)
ParFlex® Parex® (1.800.537.2739)
Waterproofing Material* Manufacturer
Laticrete® 9235 Laticrete Intl., Inc. (1.800.243.4788)
Mer-Krete® Hydro-Guard® 2000 Mer-Krete Systems (1.800.851.6303)
NobleSeal® TS Noble Company (1.800.878.5788)
* Products may be substituted with equivalent products. Manufacturer must
provide equivalency.
Hmm, I was unaware of that one. That’s new. Curious why they would recommend a waterproofing product for their waterproof product, though.
I don’t see that they would have a problem with the AD then.
Yeah and maybe that’s why they don’t provide any waterproofing steps in the install instructions as well. Most of these products are sheets membranes similar to kerdi not liquid membranes though.
So Roger, DensShield will not warranty what I am doing as it does not follow their listed installation instructions. But, the guy said that they are aware of people using various liquid membranes and that he does not see any problem with installing the way I propose. Then again he reiterated that they cannot warranty it.
I honestly don’t give two whits about a manufacturers warranty. There should be no problem with the AD, decision is up to you.
Yeah I agree but once I talked to him the install procedures do seem ok and it does save me $90 for the gallon of AD here in Canada. And that’s $90 and I’ll use at best half of it. Silcone should be fine.
Roger,
Your information on here has really helped me piece together all the random, disconnected things I knew about tiling. Thanks for doing this! I’m about to tile the tub surround in our bathroom and had a few questions I just haven’t been able to find an answer for yet. First, I’m planning to use Durock as the substrate and finish with a porcelain tile. I’ve seen a lot of mixed opinions on whether or not to put plastic sheeting as a moisture barrier behind the backer board. If you don’t put plastic, the consequences are obvious, but if you do, some say that water will get trapped between the backer board and the moisture barrier and will still mold. I know Durock is mold resistant, so I wasn’t sure if this is true, but I wanted to check first. What would be your recommendation?
Also, I’m using a 12″x12″ tile and stacking 6′ up the wall. Is there a certain size trowel I need to use for that? Or does that really matter? Thanks!
Hi Ben,
You need either a barrier behind it or a membrane over it. You NEED something, not having it is not an option if you want your shower to last any amount of time. Gravity pulls water out of the board, it will not get ‘trapped’, that’s bullshit. It is in the specs, in the book and the only proper way to build a shower. No idea why whomever told you that would tell you that – they obviously have no idea what they’re talking about. Stop taking advice from that particular source.
You need a trowel large enough to give you complete coverage, I usually use a 5/16″ or 3/8″ for wall tile.
Perfect.. I’ll put some plastic behind it. Last question. I’m tiling the shower in our only bathroom in a really old house (+100 years). The framing is anything but standard; however, the walls are solid 1″ thick boards which should be perfect for supporting the cement board. My question deals with the thickness of Durock I should use. I know they recommend 1/2″ for walls, but the problem is that the existing wall in the bathroom is only 1/4″ thick (I’ve never seen it used for interior walls before, but it looks like that cheap backing board they put on the back of furniture). So, in this case, if you’re liberal with the screws, is it ok to use 1/4″ Durock on the walls to keep everything flush?
Hey Ben,
The problem is the space between the studs, not the sturdiness of the studs. With 1/4″ backer is not strong enough to hold your tile as sturdy as it should. You need 1/2″ backer for walls.
Hi Roger!!!
I just bought your Kerdie installation ebook.
I have a couple of questions.
After I burn my Hardiebacker board with smooth side of trowel, what size notch trowel do you use for the Kerdi?
Is there a chart somewhere in your site here that specifies what notch size to use per size of tile?
I’m using 12″ porcelean.
Also, I’ve got a solid preformed base. I’m going to bring the kerdi down to the horizontal surface of the base and silicone the hell out of the flange like you explain, but the tile will come down to about an 1/8″ of the horiz. of the base. Do you also silicone between the tile and the surface of the solid base? It seams to me you could trap water between this seal and the Kerdi seal unless you leave little weep holes somewhere. Can you please explain how to do this.
Oh one more …What kind of beer do you recommend with kerdi
Thanks Roger
ps Roger I have not been notified by email on my previous questions to you
Hey Jim,
I use a 1/4″ v-notch trowel for most of my kerdi installations. The trowel size post is on the way, it’s been on the list for a while (it’s a big ass list…). I already have explained where to leave weep holes here: weep holes in tile installations
New Belgium Brewing Company’s 1554 is a great kerdi finisher. Their Fat Tire Ale is a standard stand-by. It is also six blocks from my house (seriously).
Great stuff.
If you haven’t received notifications you may want to check your spam folder or make sure I’m on your ‘white’ list in your email program. They are sent automatically.
EDIT: It could also have something to do with me receiving an automatic reply immediately after I replied to your question stating that you are out of the office.
Roger…
Got your email this time. I’ll use a 1/4″ v notch trowel for the Kerdi then, but still cannot find the big ass trowel noch per tile size list. I didnt get that in your email.
I’ll have to try your New Belgium Brewing Company’s 1554 Kerdi finisher though. I was a strict Guinness draught beer drinker but lately trying all of the goose island products. Maybe these will be bathroom floor finishing liquids.
Thanks for all of the advice.
I thought your kerdi book was very good.
Later ,
Jim
Hi Roger..
Trying to determine the new floor height up to the toilet flange.
There was a mud base that was very thick. I’m using Kerabond thinset, 12″ porcelean tiles. Can you tell me the trowel notch size and the expected thickess of it after setting. I’m puting one layer under and one layer over the hardiebacker board.
My guess would be 1/8″ of an inch per layer.
Thanks,
Jim
Using a 3/8″ x 3/8″ trowel leaves a 3/16″ layer of thinset (tile), using a 1/4″ x 1/4″ leaves 1/8″ (backer).
Hi Roger,
I cannot find on your site of favorite modified thinset.
I’m going to use your suggested 317 on the kerdie, but on the floor and walls of the bathroom I want to use a modifed.
Is there a list on here of your favs of modified thinset like you did with non modified?
If not, does HD or Lowes or Menards have a good quality Modified?
Thanks,
Jim
Hey Jim,
My standard thinset is laticrete 253. Any of the laticrete modified thinsets are good, as are mapei ultraflex 2 and 3 and versabond.
Roger,
Thanks for all the help!!!
Jim
Roger…You say that the Ditraset is the best unmod thinset for kerdi….Is the correct one D-25?
Jim
Hey Jim,
Yup, that’s the stuff.
Hi Roger,
I cannot find a 3/8 x 3/8 trowel in this town to save me.
Everyone has a 1/4 x 3/8.
Did you mean 1/4 x 3/8?
Jim
No, I meant a 3/8 x 3/8. A 1/4 x 3/8 will work fine.
Roger,
The information here has been GREAT, and I’ve also grabbed your manual on how to use the Densshield with my existing shower base. So, all is mostly well and good, with the Densshield up on the walls. Except (you knew there was an except!):
Our shower has a bench on the back wall. I’ve used Densshield for the horizontal and vertical part of the bench of course. But, when I cut the Densshield, the horizontal board has an unfinished (cut) edge that is facing the shower. I’m quite confident that this would be a big problem. How do I keep water from getting into this unfinished surface? I could cut a new piece and have the finished (yellow) edge facing the shower, but I suspect the yellow side isn’t waterproof either.
Ideally if this was just wood, I would be able to cut both pieces at a 45 degree angle and fit them together, but I don’t know how I would make a 45 degree cut with Densshield. What to do? What to do? Thank you!
Hey Brian,
Actually the yellow side is waterproof as well. When doing a bench you should either have a finished edge showing or waterproof it with a liquid waterproofer or kerdi – both of which I know most people don’t have bouncing around in their truck like me.
Thanks!
One more question: On this page, you state that Fiberglass tape should be used on the joints of the DensShield. However, that wasn’t called out in your Topical Waterproofing manual. So, two questions:
1. Do I need to use the fiberglass tape?
2. Assuming the answer is yes, do I need to mud over the tape? And, if so, what do I use to mud? Regular drywall mud wouldn’t be waterproof, right?
Notice how I snuck three questions into my second question? Sorry about that!
Hey Brian,
Yes, you need to use it. You use regular thinset with it, it has nothing to do with waterproofing. It ties the boards together to create a monolithic wall so the panels don’t move separately.
Can swimming pool paint be applied to cement backerboard to waterproof it before applying the tile to a shower.
Also, my “contractor” did a less than perfect job installing the tile, several tile appear to not be flushe against the backerboard. Can these tiles be individually removed and new tiles be attached properly?
Yes, provided it is incorrectly set tiles rather than the backerboard itself causing them to do that.
Hi Robert,
I don’t know. I do know it’s not an approved nor recommended method. Whether it will work? I have no idea. Never even used the stuff.
I have a neo-angle shower that I tiled the walls about 8-9 yrs ago with waterproof backer board and then used mastic to glue tiles on, now I am pretty sure I am getting water between tiles and backer board, I have been told I will need to pull off tiles and use a metal mesh to hold the mortar and then put mortar on the new tiles in order to make a completely waterproof wall for this stand up shower. Is this the only way to keep moisture from getting behind the tiles.
Hi Tammy,
Wow, I don’t know who told you that but they are completely mixing up two different things. Water will ALWAYS get between the tile and backer. Regular cement backerboard is not waterproof, only water stable. It should have a vapor barrier behind it or a topical membrane on the face of it. If you download my free shower waterproofing manual it will explain all of that for you, it will also help you decide on a course of action. You can find it here: Shower waterproofing manual
Easy questions: Should I use waterproofing on the bathroom floor? Not only am I imagining my future kids flooding the bathroom in about 100 different ways, but also how the shower curtain never quite clings to the shower and how most of my life there will be water next to the tub after people shower (not just me either, it can’t all just me failing at shower, nope!) Would it be useless to only put some sort of vapour barrier a foot or 2 away from the tub but nowhere else?
Second question: Is not tiling or putting cement board under the toilet dumb for some reason besides aesthetics? Quite frankly I’m scared to remove the toilet myself and put it back properly, and I don’t want to have to pay a plumber 100$ for 10min. worth of work. I mean, if I pay a professional to remove my toilet, I might as well pay one to tile my floor for me too. The apartment I’m about to leave had a leaking toilet seal for ~4 years before I finally caught on that, hey, those stains in the vinyl aren’t from my husband and his friends missing the toilet. I’m also worried about having to change pipes cuz all that flooring will make it sit higher.
Third question: How soon after applying cement board and taping/filling the spaces can I start tiling? How soon after tiling can I start grouting?
As yes, I’m aware that if I change my toilet it likely won’t fit the current tiling. I’m not too worried about that…I figure it’s very likely that when/if I change the toilet, I’ll probably want to change the floor again.
Hi Veronica,
Aesthetics is the only reason. You don’t need to move pipes if you remove the toilet – use a thicker wax ring. You can begin tiling immediately, you can grout after the thinset is cured (usually 24 hours). Technically you can grout immediately, but the tile may move and you can not walk or crawl on it, so…
I am in the process on retiling my tub surround. I have removed the old tile and drywall / mold substrate. My question is that the adjacent side walls are 3/8 drywall. I would prefer to use 1/2 backerboard. what is the best way to handle the transition.
Hi Mike,
You can use a pencil rail or half-round ceramic trim piece on the edges which can be tilted to cover from the wall tile to the 3/8 drywall. You may also be able to find a metal tile trim (schluter) which can make that transition for you.
I am currently rebuilding a bathroom shower stall. It contains three sides two which will have Dura rock or similar product as a substrate using the Kerdi system as a water proof membrane on all wall surfaces and floor.
The third wall and a small return wall are framed, that also has the bathroom door attached to it. In order to form a better connection to existing structure, it would be desirable to use a marine grade plywood skin to screw and glue all these members together. The plywood skin would be applied to the shower walls and the Kerdi system also used over it.
Two obvious options would be to skin the outside portion of the wall and drywall over it, or still go inside the shower wall and all the added layer of Dura rock over it with Kerdi.
All wall surfaces and floor will use the Kerdi system.
Thank you for your time and expertise
Hey Mike,
I would go with the durock over it inside the shower. Actually, were it mine, I would simply build a frame and durock it. It will be plenty solid once completed and tiled. I would forego the plywood altogether.
Hey Roger.
Kind of a long winded retort here but bear with me. Shower walls are up, 1/2″ backer board, taped and mudded seams, 6mil plastic sheeting behind backer board for waterproofing. I found that the silicone caulk I used did not adhere to the plastic sheeting where the sheeting ran over the tub’s tiling flange. The flange is about 3/4 to 1 inch tall around the 3 sides. Caulk was applied to flange first and then the back of the plastic sheeting was gently pressed into the caulk. Once it cured the plastic sheeting separated from the caulk. I was concerned that water might make it’s way behind the sheeting so I ended up re-sealing that area with roofing tar and sticking the sheeting to that which seems to have adhered better. Is that ok? Or was that unneccessary? Hope my dog won’t catch on fire!
Next, I am about to start tiling tub surround. I want to use a stringer to allow a the bottom row of tiles to rest on to ensure they are perfectly level and don’t slide down once I stick them to the wall. Is that recommended and if show how do you suggest I temporarily attach the stringer to the tub wall?
Lastly, I will leave a small gap (1/8″) where the bottom tiles meet the level surface of the tub and I was wondering what to do with this gap. It seems to me that caulk would be a bad idea because any water that penetrates tile and grout lines will run down my membrane and become trapped between the caulk and tiling flange described earlier. What do you recommend to do with this line. Is it ok to just grout it with spectralock?
As always thank you very much for your help!
-Brian
Hey Brian,
Yes, the roofing tar is fine. It is always recommended to bond the back of the barrier to the flange. Not ‘required’, but to my mind it is.
A lot of guys use ledger boards (the stringers) to get a level starting point and fill in the bottom row the next day. You can screw them in and fill the holes with silicone when removed or, depending on your particular backer, double-sided foam tape will also work with hardibacker, propanel and wonderboard.
You should use silicone and use weep holes.
If I use a product like redgard but want to use glass tile can I paint over the redgard with regular paint? I don’t want red showing through the glass tile. Or is there something else I can do?
Hi Carla,
It is translucent glass tile? You can (and should) use white thinset behind it. If installed properly you won’t see any of the waterproofing or substrate behind the tile, even if they’re clear glass tile.