Tile FAQ’s

by Roger

The questions below are the ones I get asked most often about tile and installation methods. Each one gets a very short answer, and where a full article exists there is a link to it at the end. Filter by topic or search for a word – if you would rather just read them all – just scroll.

Substrates

Can I simply stick tile to the drywall in my shower or the plywood on my floor?

You can but it won’t last – so no. Read this: Preparing a shower wall for tile or this: Installing backerboard for floor tile

Do I need a waterproof membrane for my shower walls?

Yes, a membrane of some sort is required. Read the article for the different types. Read this: Preparing a shower wall for tile

Does my floor have to be level before I install tile?

No it does not. Read this: Does my floor have to be level for tile?

Setting Materials

Are mastic and pre-mixed “mortar” acceptable to install tile on a floor or in a shower?

No they are not. Read this: Proper setting materials for tile

What should I use to set my tile?

It depends on where you are installing the tile. Read this: Proper setting materials for tile

Grout

Can I install my tile without grout lines?

No, you should not. Read this: Tile with no grout

Are tile, stone or grout waterproof?

No they are not. Read this: Is tile waterproof?

Does grout help stabilize tile, hold them in place, or make them stick better?

No it does not. (Epoxy grout is different) Read this: Does grout stabilize tile?

Are there any “magic” products available to remove stains from your grout and tile?

No there are not. One of the closest things to magic that you can buy is oxygen bleach. It is not bleach! It’s a slight misnomer. This is the main ingredient in products like oxyclean. It works very, very well to clean grout. More information: How to clean grout

Sealers

Should I seal (or re-seal) my tile and grout?

If you would like it to be easier to clean then yes, you should. Read this: Tile and stone sealers

Will sealing your tile and grout make it waterproof?

No! It absolutely will not. Read this: Sealers, part 2

Transitions

Should I use grout or caulk in the corners of my shower?

Technically? Caulk. Realistically? It depends. Read this: Caulk or grout in corners?

Miscellaneous

Can I install floor tiles on my shower walls?

Yes you can. Read this: Floor tiles on a wall

Question that is not here? Leave it in the comments below and I will add it to this page.

Leave a Reply Cancel reply

Tom

Roger:

I am installing a new shower but I do not think I want the tile to go up to the ceiling. If I am going to stop the tile about 76″ above the floor, should I stop the backerboard at this point also then install drywall above this point? Or if I run the backerboard to the ceiling, can Durock be painted and have a decent finish?

Thanks

↩
- Roger
  
  Hey Tom,
  
  You can do either one. Durock can be finished exactly like regular drywall, once finished you can’t tell the difference.
  
  ↩
Dale

Hi, Roger!

We are making the decision to remove hardwood from our media room 16’x18.5′), which is below grade for the most part (has one wall is all windows as house is built into hillside). We are aware of mild to moderate moisture issues (no seepage or flooding, more “wall sweat”) and run a dehumidifier all summer long. We would like to use large format porcelain tiles (18×18 and 12×24). The current floor (hardwood) is built on a subfloor that is on top of a vapor lock that is on the slab. In your opinion, is tile a smart application for this area?

↩
- Roger
  
  Hey Dale,
  
  It can be done over that subfloor if it’s solid and you install a proper substrate over it. You can go directly to the slab but you’ll need a thermal break beneath your tile. Depending on the moisture content of your slab and the amount of hydrostatic pressure ditra may be a good option. It does have vapor management built in but your slab needs to remain relatively dry normally.
  
  ↩
  - Dale
    
    Thanks, Roger!
    
    One quick follow-up question — I see lots of differing opinions out there regarding the proper substrate: Hardibacker, Durock, Denshield. What is your preferred substrate material for laying a tile floor in a below grade area like ours?
    
    ↩
    - Roger
      
      When I use backerboard it’s normally hardibacker or permabase. Durock is a pain in the ass – and messy. With your installation I would likely remove everything and go to the slab with ditra. If over the wood I would likely install an additional layer of AB ply and go over that with ditra. If using backer it would be hardi with thinset with thinset between it and the ply.
      
      ↩
SweetCyn

Hi Roger,
Love, love, love your site! I’m tackling a small half bath/laundry room, 7’2″X5’6″. Ripped out the particle board someone put down-oh joy-and discovered “4′ boards of T&G car decking”. Seems very study as a subfloor. I chaulked the grooves(overkill) and am laying thick tarpaper down, then an underlayment of 1/2″ ccx plywood in opposite direction to get a level firm base to tile upon. 1.-Do I need to leave space between the two pieces of Plywood (side by side) or the ends/sides of the plywood where it meets the walls to account for expansion?(Can’t remember which way it expands-on the ends or the sides) 2.-Using Ditra 1/8″ and 12X12 porcelain tiles. It says to use the modified under and unmodified over the ditra, get that, but is it ok to lay modified thinset right on the plywood??? Also, once you do, should you roll a weight over the ditra-walk on it or what to make it bond well???Won’t this squish the thinset and make it uneven??? How long is it ok to wait to tile over the ditra??? and finally 3.- how should I cut the 12″ tiles into 4ths to lay a staggered 12″ and 6″ tile pattern? I discovered 12″ is not exactly 12″ and with a 1/8″ grout line I’m not sure exactly what size to cut the 12″ tile down into so I get clean-straight grout lines. I thought just quartering the 12″ would work but was told no, with no other answer. Is there a particular kind of spacer brand I should use-I see a lot of warnings but no good suggestions of what to use. Thanx, a 1st timer tile job (no kidding) DIYer with no $ but plenty of moxie!

↩
- Roger
  
  Hi Cyn,
  
  1. It expands on both the ends and the sides – sides more than ends.
  2. Yes, it is fine to put modified right on plywood. I use my concrete float to embed the ditra into the thinset. You can also use a 2×4. You should not have enough thinset beneath that it will make it uneven, if it does your trowel is too large. You can walk on it immediately, or wait until the next day when the thinset is cured.
  3. Cut them in fourths. You’ll need to have twice the grout line width around the smaller tile than you have between the larger. The width of the saw blade as well as staggering the joints makes this the case. Any spacer brand is fine – they’re all the same size.
  
  ↩
John M

hey Roger,

I’m doing a total gut on a small 6 x 7 quest bath (shower, hopper, and vanity) I’m using a 36″ round neo-corner acrylic base unit with a frameless glass door and 10 x 16″ wall tiles. My questions: 1) I was planning on tiling the entire floor then setting the shower base on top (just like I would do for kitchen floor/cabinets) so that I have a perfect, clean line where base meets floor. Good idea in this room or not ? 2) I am using Kerdi membrane on the shower walls. There are only 2 walls (it’s a corner unit) and neither wall will be completely tiled the entire length of the room – only in the shower area ~ 38″ wide, floor to ceiling. The rest of the wall will be painted. How would you handle this one ? Just drywall the entire room (fewest seams) and be done with it, do 2 walls completely in hardibacker (but will tile only 1/2 of each one), or use hardibacker only behind tile and then have to deal with joints where drywall meets hardibacker (yuk)? 3) my shower base has 1/2″ thick flange, so I’m planning to mount the base directly against stud wall, then hang wall substrate so they are flush with the inner flange surface, then kerdi and tile over it. Yes ? 4) the flange is a bit over 1″ in height (from base “wet-lip” to where wall substrate sits on flange). Should kerdi and tile overhang this entire flange height or only some portion of it ?

Your sight is great. Wish I lived in Colorado and could have you do the prep work !!!!

Thanks,
John M

↩
- Roger
  
  Hey John,
  
  1. Yes. Setting those bases on top of tile will give you the cleanest transition.
  
  2. I would drywall the entire room and just install the kerdi over the drywall in the shower area.
  
  3. Yes
  
  4. Kerdi overhangs it and gets sealed to the flange to seal it all up. Tile overhangs it to about 1/16″ above the horizontal arm of the base.
  
  ↩
Hernan

I applied my third and last coat of redgard sunday night. I went through the directions written behind the 3.5 gal bucket and never saw the prep indications of wetting the hardibacker before applying the membrane. Anyways, it’s been 2 days since the third coat, and unlike some people I do not see the red gard peeling or tearing from the walls. Why would this happen? I tried scraping a small section with my nail and that stuff is really in there…
I also screwed some wood strips on each wall, leveled…in order to start tiling tomorrow (wednesday night). Is there like a time frame for the membrane to start getting weak? Also, should I trowel delicately or just do it like if it was a regular concrete surface? I’m just concerned about tearing the red gard with the trowel teeth. By the way, I plan on using a 1/4 x 3/8 x 1/4 trowel to lay 18 x 18 tile on the shower wall. Should I go ahead or get a bigger trowel?

↩
- Roger
  
  It would happen if you don’t burn the redgard into the substrate. If you can’t peel it off you’ve done it correctly – now quit trying to peel it off! There is no time limit before tile has to be installed on it. You will not tear the membrane with the trowel. You may want to get a 5/16″ or 3/8″ trowel for those bigger tiles.
  
  ↩
  - Hernan
    
    I see. Just for the sake of knowing, what do you mean by burn the redgard into the substrate? I sure as hell did not use any fire Roger.
    On a different note, I was going to tile today, but when buying thinset, I saw the versabond flex from custom, actually everything in that aisle is made by them. So the versabond flex has a tag that says made for use over redgard and also says that if you combine both membrane and flex, you get lifetime warranty on your project. This thinset is double the prize of regular fortified versabond, $15 vs $28. Is this a really good product Roger? Warranty sounds good too, lifetime! If my wall falls off some character from custom will come and pay. Anyways I want your insight on this thinset..
    In the meantime, I decided to prime, butwhen doing the ceiling some primer got on top of the redgard way up there where wall and ceiling meet. Is it ok to prime or paint before laying tile or would that affect the membrane in any way? Im not priming nor paintimg the redgard, just surrounding walls and ceiling.
    oh and I could only get a 1/2 x 1/2 x 1/2 trowel, no 3/8 found.
    
    ↩
    - Roger
      
      Burning means working the redgard into the substrate with the flat side of the trowel first. It is the same result as priming the substrate with a redgard/water mix first if you didn’t use a trowel.
      
      Flexbond and versabond are different products, both from custom. The flexbond is a very good thinset.
      
      You can paint first as long as you don’t get overspray or drips onto the redgard.
      
      ↩
      - Hernan
        
        Hmmmm well to be completely honest with you, I did not use a trowel for the red gard at any point, nor did I use no redgard and water mior priming before the membrane itself. I grabbed a roller and applied it like paint on the hardieboard. I did not wet the board, I hit edges and corners with a brush, also the seams, then rolled it all over verically, 2nd coat horizontal and let it dry saturday aftrrnoon. Sunday I gave it a 3rd coat. So no burning whatsoever. I don’t know what to expect. Should I rip it off and redo it?
        
        ↩
        
        Roger
        
        No, leave it. It’s fine. It’s normally always fine. People find out they can peel it off and all of a sudden think their shower’s gonna explode – it isn’t. Sheer force and tension force are two completely different things.
        
        If you aren’t going to do it in the manner I suggest when you ask questions – why are you asking questions? Or did you apply the redgard before asking any?
        
        ↩
        
        Hernan
        
        Roger, if I didn’t take your professional knowledge and suggestions into consideration, I would’ve been done with the shower, and I wouldn’t be showering in the back with a bucket daily. It’s taken me so far 1 month and 1 week trying to follow your guidelines as best as my diy’er persona can perform. So I read the instructions on the bucket of regard and never read anything about priming or burning etc, just trowel it or roll it on the substrate, AT LEAST AS FAR AS I REMEMBER.
        I applied the red gard, and didn’t have any doubts until I read somewhere about the membrane peeling…actually he said tearing easily…then I started doubting, and then I asked you.
        
        ↩
        
        Hernan
        
        And that was meant in a good way actually. If it wasn’t for your knowledge, I would have built a mold room already, not a bathroom.
        
        ↩
        
        Hernan
        
        I tiled part of the shower walls, and the next day I noticed a couple of tiles that were sticking out more than the rest. I have not grouted that area yet, or finished the entire wall, but I was wondering if you have any tricks, tips or suggestions to hide these imperfections or make them less noticeable. I’m using 1/16 grout lines.
        
        ↩
        
        Roger
        
        Nothing you can do once it’s set. Just ensure it’s flat as you set it. You can make up for a LITTLE bit with grout, the grout slope from one to the other will hide it a little, just depends on how much difference is there.
Bruce

Do you use a tile leveling system for floor tile, if so what brand do you recommend?

↩
- Roger
  
  Hey Bruce,
  
  Sometimes I do depending on the tile. I’ve tried LASH just to see how it works, it works fine but you need a lot of thinset beneath your tile and it will kill your thumbs. I own and use the TLS (Tuscan Leveling System), it is by far the best out there in my opinion.
  
  There is a new one Mick and Ernie (the inventors of tls) are coming out with, I should have it this week, but it looks better than the TLS. It’s still in manufacturing and distribution stages right now, though.
  
  If you know the inventors you get stuff early.
  
  ↩
Mike MM

When filling the seams between sheets of backerboard, do I need to let this dry before laying tile?

↩
- Roger
  
  No.
  
  Shortest. Answer. Ever.
  
  ↩
Brian

Hello Roger,

Just wanted to confirm your process for asking questions on threads already going from the past on you site. If I decide to ask another question to a thread from the past will you get a notification, I assume I use the “reply” prompt will notify to you of another question… yes? Basic question thanks for your time. BTW i did this scenario regarding a efflorescence problem I am experiencing.

Brian-

↩
- Roger
  
  Hey Brian,
  
  Whenever a new questions is posted it shows up on the back end of my website. All of them show up in the order they were posted, not by which post or question it was asked about. If you hit reply I get it in the same spot and the same order as if it were asked as a new question or attached to any other post or question. The questions posted are separate from everything else on the site.
  
  Being that they are separate, the ONLY way I know what someone is talking about is to view the question where it was posted. If it is attached as a reply then I have a reference to what has been asked and answered and know what the hell I’m talking about. If not I get a question like this:
  
  “so should I use the 1/8″ or 1/4?”
  
  That right there is all that shows up, in the middle of 50 other questions I’m answering. I have absolutely no idea who that is or what they are asking about. So I have to stop and SEARCH through all previous questions in an attempt to attach it to the proper thread and answers previously given – then I have to move it. Then I have to answer it.
  
  So I can either type “1/8”, or I can do everything included in the paragraph above, then type “1/8”. If you type your question as a reply to the first question asked on this site it will still show up in the same place with all my other notifications for that day. The time aspect of the thread you are replying to is irrelevant.
  
  ↩
Dan McDermott

Roger,
Thanks for all the previous replies on tile quality and neo angle shower enclosures. Is a frameless 38” neo angle shower enclosure a good or bad idea based on your experience? I was thinking it may be hard to keep a frameless shower enclosure from leaking with all that water splashing around. Do I need to go with a semi frameless shower enclosure?
Dan

↩
- Roger
  
  Again, provided it is installed correctly it will be watertight. A framed or semi-frameless will eliminate any uncertainties, but they are all watertight if done correctly.
  
  ↩
Dan McDermott

Do Noble Niches Have The Bottom Shelf Slope Built Into Them?

↩
- Roger
  
  Yes, provided you install them plumb and level.
  
  ↩
  - Dan McDermott
    
    Roger,
    
    The Noble Company Rep say they do not. What’s up with them? See below.
    
    Hello Dan,
    
    The Noble Niches do not have a slope built in. According to our Tech Dept., you can put a little extra thin set towards the back to set your tile with a little slope.
    
    If you would like to speak with one of our Tech Advisors, please call 800-878-5788.
    
    Thank you,
    
    Online Store Customer Service
    Noble Company
    800-678-6625 x128
    M-F 9 – 5 Eastern
    
    ↩
    - Roger
      
      Then he’s probably correct. The last time I used one was about seven years ago, I just don’t like them. I know they’ve changed designs since then, I just figured they’d keep the important parts – like a sloped shelf. They may have flat bottoms now like my college girlfriend.
      
      They are waterproof, though, so it’s not as big of an issue. I don’t think it makes any sense, but I’m not the guy that specs their products.
      
      ↩
Vicky

Hi Roger, my tenant saw fit to grout over the original grout between all the bathroom tiles before his departure (I have no idea why as the original grout was fine and only 4years old… ) There is clearly no bond between the two as on cleaning it on his departure the new grout is coming off in bits. Is there any way I can gently remove this new grout leaving the old behind or am I gonna have to start from scratch? What do you recommend.

↩
- Roger
  
  Hi Vicky,
  
  You can try a stiff nylon bristle brush. That may take it off. If not then you’ll probably have to remove it all and regrout it.
  
  ↩
brett

Roger

A guy I hired to remodel bath just installed 12×18 tiles on bath surround. Naturally, in the corners he didn’t get the tile straight (vertical grout lines are crooked — looks like he’s got problems with math/measurements). Underneath the tile, I had him slather on Redgard (“that red shit,” say he, “is good stuff”). Anyway, if he (or I) remove said tiles in an effort to straighten things, I’m assuming we run a decent chance of compromising the Redgard, right? Thoughts? Perhaps I can (emphasis on I) — perhaps I can tile over his job? The shower has not been used. At this point, I’m thinking I can do a better job than the “professional” I hired. Thanks, sir, for your time and thoughts.

Brett

↩
- Roger
  
  Hey Brett,
  
  About the only thing you can do is tear it out and start over. Once the thinset is cured it will take the redgard off with it when you remove the tile. Tiling over tile, while a viable option, can create more problems as well as creating issues at the outside with the thickness of the installation.
  
  ↩
Dan McDermott

I have two questions. First, I have heard that some tile at big box stores are low quality, while tiles at places like “Florida Tile” or “Daltile” are high quality. Have you found this to be true? The reason I ask is I found tile I =I like at a place called the “Tile Shop” and do not know if it is high quality or not.

My 2nd question is: do all good tiles have a quality rating that comes with them that gives the overall rating, the wear rating, etc.

↩
- Roger
  
  Hey Dan,
  
  Quality of tile is relative in a lot of ways. The biggest problem with big box tile is not necessarily quality of the tile, it’s inconsistent sizing in the tile. They have good ones and they have bad ones, just like everywhere else – Tile Shop included.
  
  Tiles have several different ratings that deal with different aspects of the product. The PEI rating and Coefficient of friction rating are two good places to start.
  
  ↩
brett

Mark:

I’m sure you’ve spoken of this topic, but i’m lazy…how do you rid tile of haze after they’ve just been installed and grouted?

thanks,

b

↩
- brett
  
  ROger (not mark):
  
  OK, what’s the secret to applying silicone between tub and shower tiles? Gasp! I drank several Pepsi Colas while working…
  
  ↩
  - Roger
    
    Hey Brett,
    
    Use a microfiber towel to clean up your grout. The secret to applying silicone is practice. Really.
    
    ↩
Dan McDermott

I was wondering if you have any experience with shower glass enclosures for a neo angle shower. I plan to use a Swanstone 38 inch neo angle shower pan with tiled walls. I was wondering if a frameless or semi frameless shower glass enclosure would keep the water inside and not leak out. Or, is it best to use a framed shower glass enclosure?

↩
- Roger
  
  Hey Dan,
  
  I have a glass guy that does all my doors. Installed properly any of them keep the water contained inside the shower without leaking out.
  
  ↩
Bruce

Roger,
I plan to tile the perimeter walls in my master bath about 45” high and finish with chair rail trim. One of the walls is a knee wall of the same height. I also plan to install purchased tile base trim. Where to start? I thought I would install floor tile first. Not sure where to go from here. Base trim first? Chair rail first? How do I compensate between slight inaccuracies between floor and level base trim or base trim and chair rail. I’ve thought about this so much my head hurts. Please relive my pain.
Thanks,
Bruce

↩
- Roger
  
  Hey Bruce,
  
  Floor tile first, then base and work your way up from there. Slight inaccuracies? If you mean thickness then more thinset behind the thinner tile or an additional substrate. The chair rail is supposed to stick out. Not too sure what you mean. If you just mean out-of-level floor then either begin at the lowest spot and cut your base tile up to the level line or begin at the highest and shim the base up to level.
  
  ↩
  - Bruce
    
    Hi Roger
    
    I do mean out of level with the floor. It looks like I have about a 3/4″ differential in hieght from the floor to a laser line measured at various points around the room. The base tile is 4 3/4″ high x 12″ long. If I compensate by ultering the hight of the base tile what is the minimal amount of material I can expect to remove with a wet saw. The base tile is 5/8 thick marble.
    
    Could’nt do this project without your help. Manuals are great. Answering questions is priceless.
    
    ↩
    - Roger
      
      I can take a slice off a tile the thickness of a piece of paper. If you are only removing material from your base tiles it won’t be a problem. If you are trying to cut a piece off to use (? pretty sure that’s not what you mean) then I have cut 1/8″ off, but normally 1/2″ is about maximum.
      
      ↩
Ken

Roger, thanks for your awesome website and sharing your knowledge. Is your dog back from the burn center yet?

I am installing a cement backer board over my OSB underlayment. Should the air-gap between panels of OSB be filled with thinset? I don’t understand why these gaps should be left for expansion of the wood and then filled with incompressible mortar.

Thanks

↩
- Roger
  
  Hey Ken,
  
  Keep the thinset out of the gaps.
  
  Dog never went to the burn center – he prefers to rock the mad max look.
  
  ↩
  - Ken
    
    Roger, thanks! How do you suggest keeping the thinset out of the gaps? Perhaps masking tape over the seam?
    
    Your dog has a lot of confidence to sport a Mad Max look. I’m getting a dog, but will wait until I’ve finished tiling the bathroom. Either that or get one of those low combustible dogs, like a hairless Chihuahua.
    
    ↩
    - Roger
      
      Tape over the seams or silicone in them.
      
      ↩
Patrick

I have just installed a triangular corner better bench. I know I fill the bench with cement and also put cement on the front. Is a thin layer of cement supposed to go on the bottom (underneith) of the bench or is that not even possible. Im asking for when i put the kerdi on the walls and bench. If there is no type of skim coat on the bottom side of the bench, will the kerdi attach to the metal? How is this done?

↩
- Roger
  
  Hi Patrick,
  
  No cement on the bottom. The holes bond the thinset to the cement inside. The kerdi will attach to the cement through those holes. It won’t be full contact, but it will hold your tiles up there.
  
  ↩
  - Patrick
    
    Roger,
    
    OK that makes sense but the is only about 1/2″ hole on the bottom (underneith) of the bench and then the rest of the contact area is metal. Is that enough for the thin set to bond to?
    
    Thanks
    Patrick
    
    ↩
    - Roger
      
      It’s enough for 1/2″ of it to bond to. What bench are you using? Thinset will not bond to metal, you’ll need to use a topical liquid on it, or nothing at all. Some guys just leave it bare, it doesn’t hurt anything.
      
      ↩
      - Patrick
        
        I’m using a better bench. What would you recommend? Cover the top and front of the bench with kerdi, And then use a horizontal bead of silicone underneath to seal it where the kerdi (that’s attached to the cement board underneath the bench) touches the metal? Or is the something else you would suggest that is typically done. Also for the better benches, typically are they just left alone on the bottom so there is no tile or anything, and the metal is showing? (I guess no one really sees underneath the bench.
        
        Thanks,
        Patrick
        
        ↩
        
        Roger
        
        They used to have more holes. You can use kerdi-fix to attach it to the metal or just leave it bare. Some people do it, some don’t. Your best option is to use a topical liquid on the bottom for your tile rather than kerdi. It will bond to the metal and you tile right to it.
        
        ↩
  - Patrick
    
    Sorry my last statement was confusing. There is one hole on the bottom. It is about one inch in diameter. Is that enough for the thin set to bond to?
    
    ↩
Becky

We tiled our kitchen floor before we found your website (3 years ago). We therefore didn’t know about the 511 Impregnator and used one of those bottles with a little brush on top that you are supposed to just put on the grout lines. It didn’t seal at all and our light taupe grout turned black, so we cut out the grout and regrouted. We are in the stage of wiping the haze off and are seeing areas on our tiles along each grout line where the old sealer got on the tile (I assume it must have been a coating sealer). It seems that this residue has also attracted/trapped some of the grout haze. Scrubbing at this does not seem to be taking it off, and we don’t want to move on to the sealing step until we get this residue off. Any suggestions?

↩
- Roger
  
  Hi Becky,
  
  You can use some of the sealer to get the old sealer off. The new stuff will reintroduce the carrier into the sealer and you should be able to buff it off.
  
  ↩
Tim

Roger,

We are considering a 12″ high tile backsplash between the kitchen sink/counter and cabinets. It is an older home (1948) and there are cracks in the wall there. Can Ditra be used in this kind of application, or only for flooring? What would you suggest doing to avoid cracks forming in the backsplash?

↩
- Roger
  
  Hi Tim,
  
  If you go over it with redgard it will take care of those cracks for you and prevent further cracking from transferring through to the tile installation. Ditra won’t really work well for that application.
  
  ↩
John

Hi Roger,

Thanks for all the insight on you website. I’ve read all I can find on the cbu to drywall transition but not the answer to my question. In a tiled shower where the tile goes to the ceiling, does that drywall ceiling to wall cbu transition need to be taped if the tile is caulked at the ceiling? If it does, do you use the cbu mesh tape in the corner and thinset on walls and drywall mud on the ceiling? And if it does, why does it need to be taped? Also is there any harm in coating the cbu and deck mud floor with Aqua Defense and joint taping the mud deck to wall corners with waterproofing joint tape prior to tiling? Thank you.

↩
- Roger
  
  Hey John,
  
  It should be, just to tie everything together so it moves as one. It’s not really necessary, though. If you tape it use thinset everywhere, it can be finished just like wall mud. If you have a liner in your floor do not put a topical membrane over the top of it. Not too sure what ‘waterproofing joint tape’ may be?
  
  ↩
Terry

I have installed a new tub I am adding a shower. I used denshield and now I’m wondering if there is waterproof tape I can use to cover the seams and screws or is the best a caulking.
Thanks

↩
- Roger
  
  Hi Terry,
  
  Regular silicone is normally used. You can use kerdi-band as well after the fact, or regular silicone.
  
  ↩
brett

Have you ever used Redgard instead of traditional shower pan liner? If so, how’d you do it? Thanks!!

↩
- Roger
  
  Hi Brett,
  
  Yes, a lot. Along with hydroban, 9235, hydrobarrier and aquadefense. You should have either a laticrete or schluter topical drain. If you mean in place of a liner (which are two different methods) then it is simply used in place of it, with the proper thickness. There are two different methods.
  
  ↩
  - brett
    
    Roger:
    
    To be clear, I mean something along the lines of sloped mortar, then redgard, then thinset, then tile. Is this correct? I checked redgard’s site and am a bit confused with the process. I am due to have a custom shower built a the guy wants to use Oatey shower liner. I’m thinking maybe redgard would be better. Thanks so much for any insight you can offer. (Would i still need special drain for above setup??)
    
    Thanks,
    
    B
    
    ↩
    - Roger
      
      Yes, you still need the topical drain. The regular drains have weep holes below the surface of the top mud deck. With redgard you’re only doing the single deck as you’ve mentioned. With a regular drain you would end up with open weep holes below the waterproofing, that defeats the purpose.
      
      ↩
Pat

Hi Roger,

I am replacing my kitchen backsplash. After removing the existing tile and dry wall, should I replace with new dry wall or cement board? If cement board, which kind do you recommend (easiest to cut, etc.)?

BTW, you helped me with the shower project a year ago. It is still holding up. Thanks.

↩
- Roger
  
  Hey Pat,
  
  Backerboard would be a better option (I prefer hardibacker or fiberboard) but in most backsplashes regular drywall is fine.
  
  ↩
Bruce

Roger,

Should I seal my light beige marble floor and walls before grouting? If I do will the sealer affect the adhesion of the grout?

Thanks for all your help.

↩
- Roger
  
  Hey Bruce,
  
  You can if you want. It normally helps with grout cleanup. It will not negatively affect the bond of the grout.
  
  ↩
  - Robert
    
    Hi, Roger,
    
    Completely love this site….very informative and entertaining!!!! I do have a question.
    We are remodeling our bathroom in our 1954 home. We have gutted the bathroom down to the studs and replaced with new drywall and Hardibacker. I was told, by a big box employee, that taping and mudding the seams of the Hardibacker with drywall material was ok…so I did so. I have seen from some of you previous posts that it is wrong to do that. Well, how to fix it….take all of the mud off, ooorrrrrr can I just put thinset over it and that will remedy the situation? I am also assuming, yes I know what that does, that I would still us drywall mud on the drywall side of a corner and thinset on the Hardibacker side.
    Found this WONDERFUL site after the fact and will not sray off any where else!
    Thanks for your help
    
    ↩
    - Roger
      
      Hey Robert,
      
      You need to remove the drywall mud. I know it’s a pain in the ass but water will cause it to fail. Yes, drywall mud on the drywall side and thinset on the tile side.
      
      ↩
      - Robert
        
        Roger,
        Here I go, off to sanding away!!
        Thanks for your help and steering me right
        
        ↩
        
        Roger
        
        Take beer!
        
        ↩