I get a LOT of questions from my readers about basic shower construction. I understand that my readers don’t consider this stuff basic and there’s no problem with that. The problem is that I end up answering the same questions over and over and over… So, to save what very little is left of my sanity (which is a number roughly equivalent to absolute zero) I will cover some basic things here so I can simply reply ‘read this’.
If you’ve been channeled to this page by one of my smart-ass comments please take no offense to it, I’m here to help. Please understand that I currently have over 12,000 comments (questions) on this site (seriously) which I’ve answered – every one of them. I’m just trying to make your life (mine) easier. I will continue to answer every question I’m asked, I’m just super cool like that. 
If, after reading through this, you still have questions feel free to ask them in the comments below.
You can also download my shower waterproofing manual which should answer a lot of questions and cover basic techniques and methods you may be confused about. Go ahead, it’s free. So without further ado (doesn’t even look like a word, does it?) let’s get on with it. (For all my readers who feel the need to correct me: I KNOW it’s actually ‘adieu’ – I was being facetious. Thanks. 
)
Leaks
First and foremost – tile is not waterproof. Grout is not waterproof. Adding sealer to your tile or stone will not make it waterproof. Your shower should be completely waterproof before a box of tile is even opened! No matter which waterproofing method you choose, proper substrate preparation is the only thing that will make your shower waterproof.
If you have a leak in your shower – stop using it immediately if at all possible. If that is not possible (it’s your only shower) have the shower repaired – immediately. If you see water leaking it is likely not nearly as much water as you don’t see leaking into your wall cavity and structural framing. By the time you ‘see’ most leaks the framing is normally already considerably compromised.
No, there is nothing you can put over your tile to make your shower waterproof if you have a leak – not even sealer. A tile or stone sealer is made to make your tile and grout stain-resistant, not waterproof. It does this by sealing the pores of the tile and stone to slow (NOT STOP) the absorption of liquid and prevent staining. It only means you have more time to clean up the spilled red wine cherry kool-aid before it stains anything.
Substrates
Drywall is not an acceptable substrate for your shower unless you are using Schluter Kerdi waterproofing membrane – that’s it. Cement backerboards are the standard and there are also other products such as waterproofed, gypsum based boards like Denshield and waterproofed, foam-based sheets like wedi or kerdi board.
Cement backerboards are not waterproof. They are water stable, which simply means that they will not swell or disintegrate when exposed to moisture or water – they won’t change size. But they are just like your driveway, they will soak in water, hold water, and dry out, just like your driveway when it rains. If using backerboards there needs to be a waterproof membrane utilized as well.
Membranes
If you are using a topical waterproofing membrane such as a liquid like redgard or hydroban, or a sheet like kerdi, do not use a moisture or vapor barrier behind your substrate. If you have a vapor or moisture barrier behind your substrate do not use a topical membrane on the front of it. This combination creates two waterproof barriers with your substrate sandwiched between them. any vapor or moisture trapped between them has absolutely no way to dissipate. This is lovingly referred to as a ‘mold sandwich’. It is not tasty. Use either a moisture or vapor barrier behind your substrate or a topical membrane on the face of it. One or the other – never both.
With that said, if you want to use a topical liquid such as redgard on the seams of your backerboard, after you tape and mud them, you can do so without problems. If your moisture barrier and backerboards are properly installed there is no real reason to do so – but if it will help you sleep at night go ahead and do it.
If you are using a topical membrane and you have an exterior wall with either plastic facing or kraft paper facing you need to cut slits into that facing before installing your substrate. If you do not it will create the aforementioned mold sandwich. Give moisture or vapor somewhere to dissipate.
Shower-tub transitions
There should be a gap between your tub or acrylic shower base and the bottom of your backerboard. If you are using a traditional barrier waterproofing method you do not need to do anything with this gap. Do not fill it with silicone! This will trap moisture running down your barrier and it will have nowhere to go. If you are using a topical method you can fill it with silicone if you want. If you are using liquid you should fill it with silicone. This creates a waterproof plane between your membrane and the tub or base so water or moisture ends up in the drain rather than in your wall.
When you tile you can tile right over that gap. You should not fill this gap with thinset behind the tile – it will crack due to movement. Your wall and tub or base will expand and contract at different rates – it will crack any cement-based product you place between the two. This includes thinset as well as grout. You do not need a solid backing behind your tile over this gap – it should be less than 1″ wide. You shouldn’t normally be walking on that tile in that particular spot. Yes, it can just hang there.
Grout
If your grout is cracking it is due to movement 99.9% of the time. Type ‘cracking’ into the search box up there and you’ll find in-depth explanations for your viewing pleasure.
If you have white, or lighter than normal grout when you’re finished grouting it may be efflorescence. This is mainly due to minerals in the water being left on the surface of the grout when the water evaporates. It is usually indicative of either incorrectly mixed grout or using too much water while cleaning the grout – not wringing out your sponge enough. This is normally only on the surface of your grout. Scratch the very top layer of your grout in an inconspicuous spot with your fingernail. If you have the correct, or at least a darker, color beneath the surface that is the likely cause. The easiest, quickest fix, provided it is only the very top layer, is to get some drywall sanding sponges and go over the grout lines very lightly. Just like burnt toast – scrape it to the color you like.
Corners and changes-of-plane
Caulk.
Disagree with me?
Like any other website I get my fair share of people who disagree with my methods or techniques – it really doesn’t bother me. I am more than willing to have a civilized, intelligent conversation about anything tile related. If, however, you simply attack me personally and act like an uncivilized ass I will call you on it – and not in a nice way. I write this blog in a particular manner, it does not mean that I take my profession lightly – I most certainly do not. If I wanted to be a pompous bastard I currently have 19 letters I can place after my name – all tile related. But I’m not a pompous bastard – you can just call me Roger.
If you are a contractor with a customer who has come here for information and I’ve told them you’re wrong – realize that the extent of my knowledge of that particular project is limited to what I’m told by your customer. It does not mean that I am ‘out to get you’ or anything of the sort. I normally limit my replies to those situations by stating the current TCNA and/or ANSI standards pertaining to what I’m told. If you disagree – please let me know in a civil manner, If you’re correct I’ll back it up – I do this everyday, too! If you’re an asshole about it expect the same in return (It’s the comment by ‘Kanela’ with the bold print before it) – and please have a thesaurus handy to interpret my reply – I’m a very well educated asshole.
That’s it for now. I will likely add to this post on a regular basis. If there is anything I’ve caused confusion with please, for the love of God, let me know. I can change this page since, you know, it’s my website and all. If you have any questions at all please ask them below – I’ll answer, really.
Hi Roger,
I have a tiling question. I will be cutting very large tiles, porcelain: 18 x 35 x 3/8″ thick and ceramic: 12 x 35 x 1/2″ thick. I need to rent a tile cutter from a local tool rental place. They are suggesting a paver tile saw instead of the typical wet saw. What are your thoughts and recommendations? And blade type as well? Can the same blade work for ceramic and porcelain? I have your tile tips book which I need to read again but I can’t remember if you mention anything about cutting extra large tiles. Any suggestions for this, such as making the cuts as straight and crisp as possible with such a long run. I don’t remember what type of “guides” there are on these cutters.
Also, for the trowel size for these very large tiles. I purchased a 1/2″ x 1/2″ square trowel at a local tile supply store which was recommended. Do you agree with this? If not, why, and what do you recommend and why?
Regarding the application of the thinset, and using the grooved side of the trowel after it is spread, at about what angle do you recommend holding the trowel to make the notches. I am hoping to be able to be consistent with this so the tiles will be flush with each other. Any tips are greatly appreciated!
Thank you,
Ruthie
Hi Ruthie,
A paver saw will work provided you put a tile blade on it. A rail saw would be a better choice. It’s made for that specifically.
1/2″ x 1/2″ is fine for those.
All trowels are made so they leave the noted amount of thinset on the substrate when used at a 45 degree angle. Just take your time with it.
Roger,
Great website! Your sense of humor is very close to my own (yes, it’s scary sometimes).
I’ve been perusing your many pages of info since yesterday when I found the crack in my 25 year old pre-cast shower wall and started planning the tear-out and tiling.
I finished the tear-out for everything but the floor pan which I had planned to save. I had planned on using the old school hardibacker and felt paper.
My question revolve around the precast floor pan. It has no lip! The old panels were just siliconed to it. It worked for 25 years as there is no water damage or mold. How would you recommend I proceed?
Hey Shawn,
Sorry for the delay – your comment was shot to the spam folder – are you a nigerian prince?
At the bottom of the tar paper fold it over out into the pan so it has a 1/4″ horizontal ‘lip’ lying onto the existing pan. Silicone the back of that lip to the pan. The bottom row of tile should cover the tar paper. A topical method would be a better choice in your situation, but it can be done with the traditional.
Roger,
Thanks for the great resource! I’ve downloaded the topical waterproofing book and am ready to get started this weekend on re-doing my corner shower. The only problem is, the acrylic base I ordered wont get to me until next week! Can I proceed with backerboard and tile, working from top to bottom, without the base? I have the dimensions of the base, so I feel like I could still get some work done this weekend, but don’t want to tile myself into a corner without the base either!? Thanks!
Hey Brent,
Provided you leave the bottom piece of backer off you can. You don’t want to install the backer down to where the base or base flange will be – it’ll be a pain in the ass to get the base in there.
Hi Roger,
A few questions:
1.Do you grout or caulk between floor and front of tub?
2. I used latisile silicone caulking and it was very humid and took a long time to harden. Could tool atleast an hour later. Seems to be better now (date on tube was 2013). Will this be okay down road?
3. Back splash and tumbled travertine. Seal then grout and enhanser? What size trowel for 3×6 and grout spacing is 1/8 or close as possible?
Would appreciate your expertise on these questions. Sorry for so many but want it to be done correctly. Latisile crossing fingers.
Thank you very much,
Paul
Hey Paul,
1. Silicone or caulk
2. It’ll be fine. If it’s extremely humid it will take extra time to cure.
3. Yes, seal, then grout, then enhancing sealer. Minimum of 1/4″ x 1/4″ trowel for that tile. I normally use 1/16″ spacing.
Thank you VERY MUCH.
One More question please. Can you tell me what to buy, an enhanser sealer, or straight sealer then separate enhanser.
I am a homeowner. What brands do you recommend that are
accessible? Was that one quaestion? I am sorry. so much to take in.
Thanks again,
Paul
An enhancer is a sealer as well, it’s simply a sealer that enhances the stone. You can use the enhancing sealer for both before and after grouting. I like Aquamix’s enhance ‘n seal, dupont makes a good one as well, I just can’t remember the name right now. Anything made by aquamix or dupont (Stone tech sold at lowes is made by dupont) are all good sealers.
Thank you for everything.
Paul
Thank you for your past help. I have another one. My tile guy already floated my tub surround. The felt behind it is only good enough for slippage and not water proofing. He wants to put Redgard on the joint where the floated cement touches the tub. Redguard will only be covering the joint on the tub side by 1/4 inch. Will that be enough to keep the joint from opening and letting water wick into the cement (and maybe eventually into the wall) Will it stick to the porcelain?
Thank you.
—Kent
Hey Kent,
As long as the tub is properly installed and supported as to limit excess movement then yes, that will be plenty. Redgard was actually first developed as a crack isolation membrane, so it has some elasticity properties. It will stick to nearly anything you want it to. And everything you don’t want it to.
Do I have a mold wandwich? The tile guy put felt and lath over a plaster wall. It didn’t come down all the way and overlap the tub lip. He went ahead and floated the surrond. There is a gap between the tub and the felt where moisture can go behind the tub. So, to correct that, he was going to use Redgard on the cement surround. Will this make a mold sandwich, having felt behind and Redgard in front, or will any moisture in the cement evatorate out the bottom? This seems like a mess to me. I don’t know what to do. Thank you.
Hi Kent,
No, you do not. A floated wall (I’m assuming he floated it with mud and not plaster?
) does not trap moisture. Any moisture between the two layers will be utilized by the cement in the mud. It rehydrates the portland and is utilized to grow more crystals in the cement. The hydrogen and oxygen atoms are separated and become a permanent part of the crystalline structure in the Portland. It’s fine.
Help! I have an old tub I thought I could keep and make it into a shower/tub. There’s no lip around the tub. It’s flat. The tub is up against a plaster wall from 1937. Is there any way to seal the seam between the tub and wall using a membrane, and keeping the original plaster wall? What would you do? Thanks.
—Kent
Hey Kent,
I would use kerdi and leave the bottom long. Once installed on the wall silicone the corner between the tub and wall to adhere the kerdi, press the kerdi down into that corner so it fold it from the wall down onto the tub, install the tile then cut the membrane right under the edge of the tile.
The tile will cover the kerdi (where you’ve cut it off) and the silicone bead prevents water from creeping back up under the kerdi.
Hi Roger,
Back to my daughter’s bathroom. Took out all the grout and used the Laticrete grout(new one) Seems fine.
Only had one silicone caulking tube (same color for change of planes) so decided to grout corners with rest and between tub and tiles down side and in front of tub using caulking.
This is temporary for a year or so until they get funds to rip out and try schluter system.(that will be my next group of quaestions for you) Had some water issues prior to them moving in and want to help somewhat alleviate for time being. I do understand that if not properly waterproofed behind no good but do not know until tear down time.
I love using silicone(especially laticrete but I have been cleaning the old caulking and want to make sure the new silicon will adhere.
What is best way to go about cleaning so you know it will adhere. You should do a DYI. I am sure others would appreciate it.
So Many questions and you always come through. Thank you a thousand times.
Paul
Hey Paul,
Clean the tile and whatever other surface you’re siliconing with denatured alcohol. Make sure everything is scraped off then just wipe it down with that.
Roger,
Do you think I will be okay for a while with grout in corners? Also around the soap dish should I caulk? There is a window shoulder high gainst out side wall. Best to caulk?
Thank you,
Paul
Anything you can silicone would be best. The grout in the corners will be fine short term, I just don’t know how short term.
Thank you Roger.
I have a few questions about a couple of the more complicated areas of my custom tile shower.
Topic #1 is regarding what to do with two changes of plane that are outside corners instead of inside corners. One is for the edge of a bench seat that we have framed in and plan to cover with a substrate of hardiebacker and redguard. The other is to wrap the custom tile shower surround around a 4×4 weight-bearing post (my shower base is slightly L-shaped to accommodate this). Do I still caulk those outside corners with silicone? Can I use bullnosed tiles on them, particularly the bench to make sitting on it more comfortable? Now that I think about it I have the same general question for the margins of my niches as well.
Topic #2 – I’m only tiling about 6 or so inches around the vertical 4×4 post, and it is covered by 1″ wood on the one of the sides that I will be tiling. This tile surface will not be taking very much direct contact with water, but it will be supporting a frameless glass panel. The shower base I am using is a KBRS tile-ready Shower Base with their Hard Curb upgrade so I’m not worried about screwing into the curbs with the glass partition anchor hardware. But do I need to worry about moisture being introduced through the screws for the wall glass achors that will be going through my tile –> redgaurd –> hardiebacker –> 1″ wood –> 4×4 post? If so, how should I mitigate that?
P.S. You rock!
I’m baaaaaack, already, with a picture this time. It nicely captures both the bench and the funky corner with the angled wall due to the staircase that clips part of the bathroom that gives me much anxiety and deprives me of much sleep as a DIY tile novice:
http://farm8.staticflickr.com/7140/7737790726_ea1bd2a306_z.jpg
Imagine a frameless glass partition jutting out at 90 degrees from the point of the half-demolished plasterboard, cut to accommodate the angle. Anything to the right of that imaginary glass will be tiled and within the shower, anything to the left of the imaginary glass will be outside of the shower. The photographer is basically standing where the glass shower door will swing open.
Same answer.
Hi Kate,
Outside corners should be taped and mudded, not siliconed. And yes, you should use bullnose on them. Anywhere you have an outside change of plane looks better with bullnose.
Drill a hole smaller than your glass fastener screw and fill it with silicone, then install your screws right into it. The silicone seals the penetration as you screw it in.
Roger,
Computer fouled up spelling for name.
Thank you
Paul
Hi Roger,
I am filling the voids on my backsplash with joint compound. Will there be a problem with the tiles adhering to it(took off old tiles and this was result).
What type of mastic shall I use for this job?
Last- when using silicone caulking what do you use to smooth it out (finger with soap water, 409, just finger?
Thanks,
Preremstaul
There should not be a problem with the joint compound in a dry area such as a backsplash. I don’t know what type of, or even if you should use, mastic. You did not say what type of tile or stone you’re installing. Use mastic only if your tile is ceramic or porcelain and less than 8 inches square. If they do not meet those requirements use thinset.
Hey Roger,
Me again, same job, different questions. So I’m to the point now where I am ready to tile. New tub in, new window in, Hardiebacker up, multiple coats of redgard slathered on and been drying for days. My first question, I am doing 6″x8″ tiles(putting the 8″ length on the horizon) what is the proper trowel size to use? I have a 1/8″x1/8″ round trowel(the thinset left on the wall will be rounded instead of squared flat top), is that adequate to hold the tiles or do I need to step up to 1/4″x1/4″ square trowel. I like the 1/8″x1/8″ cause it’ll leave a smaller caulk line on the side where my edge tiles meet the sheetrock. But if it is not going to hold the tiles and I have to step up in size, I’ll deal with a thicker caulk line on my edges. My second question, how do you recommend starting your first(bottom?) row of tile? Do you measure up a tile size, taking into consideration the grout lines, screw a straight board to the wall and start your tiling from the there up using the board as a support? Or do you go up from the tub an 1/8″ and start right off the top of the tub? I’ve read numerous numerous threads that people say do it both ways because it’s easier and the other way is impossible and vice versa for both versions. I’m leaning towards screwing a board up to prevent from chasing tiles down the wall before my thinset sets. Please let me know how you recommend doing and an suggestions you might have. Love your site, love your posts and they have helped a ton so thanks for that! Hope the dog is okay.
Bane
Hey Bane,
A 1/4 x 1/4 would be the minimum. Sorry.
I normally start right at the floor or tub and work up. I use lasers ’cause I’m a big Star Wars fan.
I shoot my line one full tile height from the lowest point on the floor or tub (plus 1/16″) and cut my bottom row if needed so it sits right at that line. That gives you a level line from that point up whether or not your tub is dead-on.
I’ve also used boards and started up one tile as you describe. There is no real right or wrong way to do it – whatever you feel comfortable with. Keep in mind that you’ll need to fill the fastener penetrations with silicone after you remove the ledger boards.
Awww man that bums me out a wee bit. I guess I can’t be too surprised that ‘something’ isn’t going the right way for me
poor me, lol. I like the idea of the ledger since I’m scared my first batch of thinset might not be spot on and that’ll compensate for me being green. Thanks for the response and the tips. I’m sure I’ll be back here at some point to pick your brain about something else I’m about to screw up 
. Thanks again Roger, you 
!
Bane
I have started my first istallation of Kerdi and have 2 issues.
1) Either I loosened some of the mud bed and had a rock under the Kerdi, or I didn’t clean up good enough. Either way there was a couple of little rocks under the Kerdi when I embedded it and they poked through. I poked the Kerdi enough to remove the stones but now what do I do with the small hole remaining? I am thinking Kerdi fix or a 4″ patch???? It is on the floor of the shower.
2) I embedded the kerdi in the thinset and saw the ridges from the trowel disappear joyfully. However, when I run my hand across it now, there are spots that ‘sound’ different as if there is a void of thinset underneath. It doesn’t seem to have flex in those areas, but if I tap on those spots, it sure sounds like there is a space below it. There seems to be a few spots like that. I suppose it is possible that I had an air bubble trapped and just moved it around as I embedded the Kerdi. I am a perfectionist and this is driving me crazy. What would you do?
Ok. After getting home, I did a thorough inspection of my work. And I must say, I am disappointed, no, I am pissed.
So, I in fact didn’t get all of the ridges flattened out (there is a 2″ x 10″ strip of ridges under the kerdi) and I found like 10 spots the size of a half-dollar or so that are not adhered. I want to fix it correctly. I am guessing I didn’t have my thinset thin enough. Is it possible to tear this out? Or cut out the spots, level them with thinset and lay a new piece of Kerdi over the existing? Or cut each spot, level it and patch each one?
Hey Skeeter,
You can patch each individually, but it would be better, quicker and easier to cut those out, level them and install a new piece of kerdi.
Thank you for all your advice. I feel very good about tiling and waterproofing as opposed to a year ago.
My daughter bought house and helping out. Tiling her tub and going to go step by step with you and would appreciate your input
1. Make sure wall are even with tub flange when stripped. (minus 1/2 inch backerboard).
2. Backerboard up and tape joints with thinset mortar in corners etc.
3. Bring bottom of board to within 1/4 ” of flange and and silicone between flange and board.
4. Redguard or laticrete product(I know you like their products) 2 coats over backerboard.
5. Thinset and tile and bring tile over backerboard to 1/8″ of tub.
when done tiling caulk planes and between tub and tile leaving 2 weep holes –one on each side.
**off on tangent here bear with me****Would you leave weep holes if you were doing an older tub job that just needed to be caulked not knowing what was behind older tile?
—What about where turn offs are? Best way to waterproof those if using redguard?
Feeling good and lucky I have your backing. Thank you again.
Paul
Hey Paul,
3. It’s normally easier to get a good, solid bead of silicone if your gap is only 1/8″ or so. 1/4″ is a large gap when you are installing silicone.
Yes, I would leave the weep holes. Water will get behind the tile, no matter what the substrate. Whenever you can give water a place to drain it’s a better solution.
As you install your tile place a bead of silicone around the cutout for the shutoffs. Install your tile sandwiching the silicone between it and the redgard. This creates a dam which water will run around rather than into the wall.
Roger,
Thank you for all your help.
Paul
Hi Roger,
On to my backsplash and a few more questions about tub.
I bought the tumbled travertine 3×6. I was told by tile distributor to put up and then grout(grout would get into areas that were open and then seal. Is that correct. Or seal first and then grout.
Also what is best grout that does not change color and caulking is similiar or dead on. Distributor likes polyblend(not big store) and can I use the laticrete acylic silicone for plane changes.
How much longer will the silicone last as opposed to acrylic silicone in a wet area on a regularly used shower?
Thank Roger.
Paul
Yes, grout first then seal. Laticrete grout and silicone are dead on. Polyblend, in my opinion (as well as mos pros I know), is the absolute worst grout on the planet – seriously.
There is no such animal as acrylic silicone. There is ‘siliconized acrylic’, but it’s acrylic caulk. Silicone will last considerably longer than anything acrylic-based. Silicone will not lose it’s elasticity – acrylic will. MANY factors play into the time that takes to happen, but silicone will usually last almost twice as long.
Thank you for all your patience and answers.
Paul
Roger: Do the screws in the backerboard need to be “taped” like the joints or just use thinset over them ?
Thanks a lot for taking the time to answer all these questions, keep up the great work.
Chuck
Hey Chuck,
Just thinset, the barrier behind will twist around it and seal the penetration or the topical membrane will cover them.
Roger: Is there any issue with using Ditra Set on Hardee backer under travertine ?
Thanks for your continued support !!
Roger: Crap………..should have told you its in the shower…..
Thanks again.
Hey Chuck,
No problem at all – that’ll work fine.
Dear Floor Elf,
I love you. I wish I had found you sooner. Unfortunately I found somebody who said that it was FINE to use Simpleset premixed “thinset” for porcelain tiles on the walls of a tub surround. Apparently what is called “thinset” isn’t really thinset. Damnit. And then I hate to say this but I kind of got carried away with the Redguard around my niche and kind of did a lot of the CBU. THEN I read the part on the bucket that said “don’t use it over a waterproof membrane”. My tile job looks so beautiful. How soon till it falls off??? sad face. Susan
Hi Susan,
I have no idea when, or if, your tile will fall off. I cannot guarantee a failure, I can only recommend and instruct on methods guaranteed not to fail. If may be just fine, if may begin to have problems in three months. There is no way to tell. Just keep a close eye on it and watch for cracking in the grout lines where the grout meets the tile. A crack there is indicative of a tile moving.
Hey Roger,
You’ve answered many a question for me and I have another. I am planning on tiling above a shower surround(20″) and the 2 short walls are wide enough to put wonder board, but the length of shower, the lip is only wide enough for tile. Can I just use kerdi membrane over that? Or something else? Thanks in advance.
Janice
Hi Janice,
If the top of the shower surround is above the shower head you don’t need to put anything up there. If you want waterproofing up there you can just use kerdi over the drywall. If you put wonderboard on the side walls without removing the existing drywall you’ll have 1/2″ edge of the wonder board sticking out – whaddya gonna do with that?
We used 1/4″, so it doesn’t stick out too much. I am texturing the walls and hope to use some of that for the difference/caulk/bull nose piece. I guess I made it more complicated. Are you saying on any walls you don’t need to use a backer board?
I’m saying that any walls above the level of the shower head do not technically need waterproofing or backerboard. While it’s always a better idea, it’s not required.
you are right Roger I did sign Dick because a friend of mine and myself were using same email.
New project at my daughter’s home. I am into tiling due to your encouragement and expertise.
I am taking out all the grout in my daughter’s tub surround and want to regrout and caulk as you have suggested at plane areas. My question is until I retile (which could be in next year). Newly bought home and not sure what is behind walls and how the shower was built. Could of had a leak in past.
What type of grouting and silicone caulking would you suggest so I can keep both same color. I know you like latisil products(epoxy and caulking) actually I used latisil caulking on my shower and accucolor grouting and got a close mathch on the shower you helped me with this Fall. Not easy to get laticrete products. Is there any special grouting and caulking with the same color match that you would use. I live in Mass.
I have said this many times but will continue. Your site is the best out there.
Thank you
Paul
Hey Paul,
No worries – you can sign with any name you want.
And if it is a completely separate project, as your is, a new thread is no problem at all.
Most grout manufacturers make matching caulk for their grouts. Mapei normally has the caulk right there with the grout in Lowes, same with polyblend grout and caulk at HD – although I HIGHLY recommend against using polyblend. In my opinion it’s one of the worst out there.
Use any brand grout you want and if you want 100% silicone with it and can’t find it I can always cross-reference the colors for you with what you have available. Just let me know the color and brand of grout. If you are going to replace the tile within a year or so regular sanded caulk should work fine – you don’t need to worry about the loss of elasticity in that time frame.
hi Roger,
Thanks for response. Does Mapei have silicon and is it well thought of? If so I will use their grout and caulking. I agree the polyblend at HD is not my cup of tea.(Used Latisil on my shower and loved it.) Difficult to get updated caulking from latisil in my area.(eastern Mass.)
Getting back to the removal of grout. How much do I have to remove?
skinned original and took about 1/8. Is this okay?
Thanks agin
Paul
Mapei does have silicone – in Europe.
I will sometimes order latasil over the internet to match the color (I have cross-reference charts if you tell me the color) and TEC also has silicone that matches a lot of them – that’s usually readily available if you know where to look.
You want to remove at least 2/3 the depth of the tile. Grout bonds to the sides of the tile – not what’s underneath it.
if the tile will be changed within a year can I use acrylic based latex. I have heard this performs well.
Thanks for everything Roger.
Paul
You can use whatever you want to use. I can’t guarantee that it won’t fail within that year, though. It will likely be fine for that amount of time.
Roger,
I live in eastern Mass. and I am having a difficult time getting straight silicone. Everyone has acrylic silicone. Went to Lowe’s etc. Rven called a laticrete rep. Waiting to hear from him. He was a good resource last time. So difficult to get good products that are updated locally without sending away.
One more question. I have heard GE silicone 1700 Sanitary is good easy to use product but again do not know where to get it.
Like your opinion.
Thanks again for all answers.
Paul
That is a good silicone. Your rep will let you know the best place to get laticrete products.
Roger,
Just asked a question this morning and now I have decided to do my kitchen backsplash. New granite and want the backsplash to be travertine(tumbled).
Is this a good type to use? I know I have to seal. Can I use epoxy grout from laticrete on this type? I have never used the epoxy(on my shower project) Have shied away due to all the steps and time mixing and setting up(have read your discussion on it).
Felt this would be a good place to learn and try in a small area, plus a backsplash is a good place for stain resistant grout.(area is about 24 sq. feet)
Your opinion please. Thank you again.
Paul
Tumbled travertine is fine provided you seal it well. A honed (flat, smooth surface) would be better, but if it’s sealed tumbled is fine. Yes, you can use spectralock on it without any problems.
Elf: Two questions:
Backer board meets drywall, perfect transition but its green drywall and I understand thats not a good thing, wondering about putting silicone on edge of drywall where backer board butts up against drywall so as to protect drywall from getting moist, is that acceptable or ?
Gap between tub surface and backer board is about 1/16 or 1/8 ” do you fill that with silicone or caulking when you are done tiling ?
Thanks and keep up the great work !
Hi Chuck,
Yes, you can silicone between the backer and greenboard.
You want to silicone between the tile and tub and make sure you leave weep holes.
Roger,
We built a shower with the mold sandwich situation you have described but we wanted to be sure the shower was waterproofed. We altered the size and made a few mistakes along the way. First we framed in an angled corner shower (cement pan, linercement board, moisture barrier and all), then we decided it wasn’t big enough so we re-angled to a rectangular shower, glued more liner together with the glue specifically made for the liner, then filled in the additional space (under and over) with cement. when the cement dried there was a thin crack between the old and the new. I then put homelux on the walls (cement board/moisture barrier) and floor (cement/liner/cement… and tiled. But if the Homelux, Kerdi, Redgard or other waterproofing systems are supposed to be waterproof then why would mold get in between? I thought it would be the easiest way to make sure it was fully waterproof without having to start over. What do i do now that it is already tiled?
thanks, Cheryl
Hi Cheryl,
There’s nothing you can do now that it’s tiled. ANY moisture between those barriers can enable mold growth – this includes moisture in the substrate before you installed the homelux as well as dissipating moisture from the adhesive. I have never, however, guaranteed that it will happen.
I cannot guarantee a failure, I can only recommend methods guaranteed not to fail. Most failures are a combination of more than one incorrect procedure – it’s rarely only one thing. Your shower could be perfectly fine for however long you wish to keep it. The mold sandwich describes a situation that MAY happen, it’s simply a possibility. Removing that possibility, to me, is the best practice. That does not mean that your shower is doomed to failure.
Just keep a close eye on the changes of plane and make sure it’s nice and solid once in a while. Don’t lose any sleep over it.
Roger!
Ok, im trying to do a curbless shower in bathroom that i’m gutting. It needs to be curbless for wheelchair access for my brother. Floor is currently1x4 tongue and groove. So these are the steps that I plan to use:
1) cut out 1×4 planks in my shower area
2)Notch joist to give me depth for my slope
3)sister joists
4)go atop of 1×4 on non shower area with plywood (to decrease notch out
depth in shower area)
5)install drain in the shower area
6)plywood, tar paper and lathe shower area
7)deckmud preslope to drain
*8)lay and cut 30 mil membrane in shower area
*9)deckmud
10)redguard over shower walls and non shower floor
Could i skip step 8 and 9 by just doing the whole floor and going atop my deckmud with redguard?
Hi Brian,
It’ll work fine. It’s actually better to forego 8 and 9 and use redgard for everything. A single slope is much easier to work with on a curbless and enables you to tie it into the transition without problems.
Roger that!
Now is I go with the single slope and redguard would I silicone around the drain then redguard atop of the drain?
Thanks
Brian
Nope, you would create a divot in your deck mud, paint the redgard over the deck mud, down into the divot and onto the lower flange of the drain, let that cure, then fill in the divot with deck mud and tile the whole floor. Silicone will clog the weeps – you don’t want to do that.
Ok I believe i have the idea down with redgard? Should I use mesh as well over the lowe flange with redgard?
Another question would it be better if I used plywood over the joist then hardi backer over the plywood then apply redgard?
Yes, use mesh tape inside the divot with your redgard. Yes, it would be better (necessary) to have plywood over the joists then backer over the plywood.
Ok a few more questions before I start my project this weekend… How long do i need to let the deckmud dry before I go over it with redgard?
You are supposed to wait 72 hours – 3 days.
Roger,
The east side shower will is an exterior wall. The house have tyvec house wrap. I am using redgard over durock (haven’t applied the redgard yet). Am I creating a mold sandwich if I do this? I think it will be fine, but need your advice.
Hey Chris,
No problem at all. You still have an open wall cavity between the two barriers. It’ll be fine.
My plan is to use a breathable Italian plaster (marmorino) on the shower walls and have a tile curb onto the stained concrete floor. Do I apply tiles before the plaster? Should I silicone the gap between Hardiboard and floor first? Does this make you want to run screaming from the room?
Thanks, Ginny
Hey Ginny,
Are you installing the venetian plaster directly to the hardi? If so – what type of waterproofing will you have? And how will your curb be waterproofed? Or are you waterproofing anything? The tile/plaster first question depends on the waterproofing of both the curb and the walls. You need to ensure that your wall waterproofing overlaps the curb waterproofing, then install your curb tile, then plaster. That’s how I’d do it I think. That way your plaster overlaps the curb tile giving you a better lapping order. If you went tile after plaster you’d be relying on the sealant at the ends of the curb to keep most of the water out from under the curb tile.
I have three kids – not much makes me run screaming from the room.
And believe me – I’ve heard much worse ideas. Yours is actually a viable installation.
This may be a little out of scope, but after the curb for the shower gets tiled, I am putting frameless glass on top of the curb. The frameless glass sits in a U channel that gets screwed to the curb. But if I screw it to the curb, Im going to pierce the liner under the tile. Can I just liquid nail or silicone the U channel to the curb or am I missing something else? perhaps use short screws that only go into the mortar for the curb?
Hey Kristopher,
You can either silicone the track to the curb (preferred) or drill the holes into the curb for the fasteners and fill them with silicone before installing the screws into them. This seals in and around the penetration as you install it.
Hey Roger, I am doing the topical floor and walls and using the laticrete drain so for figuring the slope would I use the height at the edge of the drain flange to the furthest corner (approx 1 1/4″ high by 3′ 4″ to corner from edge of drain to get the height of the mud deck around the walls? so I would be 3 1/8″ at the walls? not good at standard measurement fractions so rounded up to the nearest 1/8″…..I think? Also do you have a preferance when doing the backer board as to short walls first long walls second or start at one wall and go around circular? wasn’t sure if it made any difference in corner joints or not.
Hey Gem,
Nope – 2 1/8″ at the walls, not three. 1/4″ / foot x 3.3 feet = ~7/8″ + 1 1/4 = 2 1/8″.
Order of the backer makes no difference, whatever way works out easiest is the correct way.
Hi Roger,
Great site! I have a question about transitioning from a PVC shower pan liner (Shower curb) to ditra on the floor. I would like to keep the floor waterproof. Would you just lap under the pvc curb with kerdi or have the ditra come up and under? or another way? Thx, Pat
Hi Pat,
About the only way you would be able to have a definite seal would be to run the kerdi under the curb, install your curb as normal, run kerdi halfway on the ditra and halfway up the face of the curb (on the outside), install your liner and silicone the back of it to the kerdi. That would give you a watertight seal at the outside of the curb which will withstand any normal use.