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 3000 comments (questions) on this site 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 – 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.
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Dear Mr. Elf,
I’m the guy who recently posted on Facebook that we’re about to tackle tiling the walls around our tub/shower, and my wife was gonna attempt it with advice from the friendly guy in the orange apron>>>hahaha! Also, I have the possibly faulty wiring in my house, if the project doesn’t turn out right.
The wife MUST have these 16″ x 16″ tiles she found. But the tub/ shower plumbing is centered about 13″ from the long wall of the tub. My thought is, centering one 16″ tile over the plumbing, then having a 5″ width tile toward the inside wall and a 9″ width tile toward the outside would look better than having the plumbing sticking out 3″ from the edge of the inside (whole 16″) tile. We only need a 32″ total width for that wall, and I am a plumber, among other things…I could move the stuff to where it was centered 16″ from the inside wall, right at the tile joints, but then the plumbing would not be centered over the tub…would the 5″ tile to the left and the 9″ tile to the right look better, or the plumbing protruding way off center of one tile?
Hey Jeffrey,
I find that once the whole shower is put together you’ll never notice whether or not the plumbing is centered in regards to the tile – you will notice if it’s off-center from the tub. If you don’t use a full tile beginning at the outside of the tub, especially with that size tile, I think it’s really not going to look right. It’ll look silly if you have tile large enough to span that area with two tiles and end up with one full tile and two (unequal) pieces. Don’t alter your layout due to plumbing locations – it normally ends up looking weird.
MAN that was a quick reply!!! You are awesome!!!! I will buy some of your manuals tomorrow!
What trowel should I use for a 12″ x 12″ offset mosaic marble sheet of tile? The first layer of thin set is for the kerdi. Most of that gets pushed out. So what does that first layer plus the kerdi add in depth?
Thanks for you patience,
Grant
I understand the first layer is for kerdi – I also understand that if you squeeze out most of the thinset you’re doing it incorrectly. If you use a 3/8″ trowel the layer of kerdi with the thinset should be 3/16″. If you use a 1/4″ trowel it should be 1/8″. If you use a 3/16″ trowel (recommended for the kerdi) it will be 3/32″. It is nearly impossible to give you a precise depth of all your layers – we do not rely on the needed height or depth of our installation to dictate our trowel size, we rely on knowing which trowel is appropriate for the given tile, substrate, inconsistencies, etc.
If you need a specific height or depth for your overall installation you need to build the substrate shy of that and adjust the amount of thinset used to adjust the tile out to whatever height you need. As you are installing the kerdi you just want to bed the kerdi into the thinset – not squeegee the kerdi onto the wall. You lose bonding strength that way. It is akin to brushing thinset onto the wall and kerdi and smoothing it up there.
I need to know the depth of my finished tub/shower wall for the plumbing. I have 12″ x12″ sheets of random mosaic tile 3/8″ thick and 1/2″ cement board. How much do I add for the kerdi membrane and the 2 layers of thin set? For instance if I were to use a 3/8″ notch trowel what is the approximate depth of the thin set after the tiles are installed?
Thanks,
Grant
Hey Grant,
Two layers with a 3/8″ trowel will give you 3/8″. So with the mosaics, backer and thinset you’ll have 1 1/8″.
Roger
I am tiling the tub surround does the kerdi board work good for a beginning tiler? Also we have what my father in law calls car decking or 1×6 flooring what is the preferred method for substrates. I would like heated tile floor and the ditra, but only have 3/4 inch between the hallway floor.
Thanks
Dawn
Hi Dawn,
Kerdi board is one of the easiest methods you’ll find to waterproof a shower substrate. It works very well.
There is no way you’ll get a proper substrate, with or without heating, to match up with your hallway. You need a minimum of 1 1/8″ double-layer of wood above the joists, plus a proper substrate for bonding the tile to (that can be 1/4″ backer or ditra at about 1/8″) plus your tile – with what you have the wood and ditra with tile will take you at least to 3/4″. In-floor heat is going to add an additional 1/4″ or so. You’ll need some sort of transition to your hallway – they can’t always be level.
Roger
Can I do 1/2 plywood on the 1 by, then heat, ditra, tile or do I need backer board on top of the plywood? Or do you recommend another approach?
Thanks
Dawn
You can do it that way – you don’t need the backer if you don’t want it.
Roger,
Thank you so much for this site. I’ve learned a lot from reading your articles and appreciate your dedication. I have a question for you regarding tiling a shower wall.
1. When installing the backerboard, should I put it above the tub flange or overlap the tub flange? The tub that I am thinking about getting shows in its installation that I should use a 1/4″ furring strip on the studs so that the backerboard will not bow out at the bottom over the flange. If I use a furring strip would that defeat the purpose of the moisture barrier? Or would I just put the vapor barrier over the furring strip?
2. Also, if I do put the backerboard above the flange, would the tile that overhangs the flange be brittle? Or would I need to put something in the gap?
Sorry if these have been answered previously. I’ve tried to read/learn as much as I can regarding this but am having trouble finding answers to these questions. Thank you in advance for you help!!
Hi Blake,
You can do it either way. If you use furring strips place the barrier over them. It works just as well. If you go to just above the flange there does not need to be support behind the tile over the flange, it just hangs there. Anything you place back there is going to crack.
So we’re into the walls of our bathroom replacing all the plumbing/electrical, and we find a repair from the previous owners to the master bath sink done with……PEGBOARD!
Talk about redoing 1970s shit and totally wrong home maintenance.
Hah! Wow. That is what I refer to as ‘quality crapsmanship’.
Our entire life for the past 14.5 years has been redoing the original builder’s 1970s crap, plus the previous owner’s cheap-ass non-upgrades/repairs. Can I send you some pix of what we are doing in the walls? Where do I send them? These soldering pix are incredible. He should come work for you.
I’m actually working on a page where my readers can upload photos of finished projects as well as the ‘crapsmanship’ they run into in the process. When I say I’m working on it, I mean I’m actually doing it tonight – so great timing.
Check back tomorrow morning for a new tab in the menu to upload pictures.
Not that I’m anal or anything, but….considering I’ve had some adult beverages tonight and feeling very free with my input…Is there another email that I can discuss this stuff with you? Not on this board.
Yup, you can always email me at Roger@FloorElf.com
Hi Roger,
What do I need to put as a backing for new backspalsh in kitchen? Can I put directly to sheetrock.
Great site and info is terrific. Thank you
Paul
Hey Paul,
You can install a backsplash directly to sheetrock if you want. You can also replace the sheetrock with cement backerboard. For a kitchen backsplash it really doesn’t make too much difference.
Thank you, Roger.
Hi Roger,
First of all, excellent site! It is very informative and entertaining.
My problem has to do with a tile repair in my shower window. I rent an apartment in a pre-war building in Brooklyn. It can get humid here and there is no extraction fan—just the small window. The window has a wood frame that has been tiled over about 2/3 of the way up. The tiled ledge at the bottom of the window had loose tiles that have been “repaired” once before but water is still getting behind the tiles. If I owned the place, I would have the shower torn down and redone correctly but that is not an option.
Water does settle on the ledge but I am pretty good about passing a squeegee along the tiles after I shower. The tiles on the window ledge were getting loose and turning black on the edges (again!) so I decided to remove them. I was shocked to find that the tiles were laid down with mastic right over the painted wood windowsill! The window has a metal frame and the windowsill comes up against it. The windowsill extends about 6 inches with a 2” wood trim piece that lays on top against the window that is about ¼” high. A lot of mastic was used under 4” square tiles to create a slope over the wood trim. Then a tile with a slight bullnose edge (cut about 2” wide) was used to meet up with the tiles on the shower wall. There was a slight sag where the 4” tiles met with the edge tiles. The water collects there, the grout falls off and the water gets behind the tiles.
After I removed the tiles and the damp, moldy mastic, I let the wood dry. The damage was not as bad as I thought. I used paint stripper to remove the old paint and scraped away any soft, wet wood that I could get to. I bought a wood epoxy kit to treat the wood. From what I have read on your site, I know that an old wooden window sill is not a good substrate for tile. The problem is that there is no room for backer board. I don’t want to take off a row of tiles that are on the wall of the shower to make room for the backer board because new tiles were just applied over some old ones. That is a whole other can of worms.
But I want to make sure the windowsill does not get any more water damage. The wood epoxy putty that I am thinking about using says it is waterproof. Can tile be attached to wood epoxy? I guess the question is does thin-set adhere to wood epoxy? Should I forget about the wood putty all together and apply waterproofing (either liquid or sheet) to the wood windowsill directly and then tile over that? I am not sure if that will work because I was thinking of using the wood epoxy putty to create the slope. Is that even a good idea? Should I add a piece of wood to the window sill to make it even with the trim piece and work from there?
If I am not explaining myself well I can always send a picture.
Thanks!
Hi Roger,
It’s me again. The more I think about it the more I realize that I do need to use a backerboard over the wood windowsill and trim.
See, I learned something from your site after all. Shortcuts never work!
This is not my window but it gives you an idea of what I am trying to describe:
http://www.hgtvremodels.com/home-systems/choosing-the-right-windows/index.html
I stripped the wood of all the old paint. How should I treat the wood before putting on the backerboard? What is the process: Wood, waterproofing, backerboard, waterproofing, thin set, tile, grout and caulk? I want to be sure to avoid a mold sandwich!
Waiting for your reply…
Thanks!
Hi Michelle,
I actually have a fix that will work for you. You can use thinset and create a slope right over the wood feathered down to the edge of the sill so the tile will still meet the wall tile. Let that cure and cover it with redgard. Once that cures you can install your tile right to it. Water will get beneath that tile, no matter what you do. Provided you have the slope and the waterproofing behind it you won’t have problems. The thinset will give you the slope and the redgard will give you the waterproofing.
Thanks for the fix, Roger! I am so glad I checked with you first.
Roger,
We are purchasing an unfinished home and the shower has a can light roughed within the shower. The shower is roughed for steam as well. This seems like a no-no to me. Can you shed sarcasm on this ;-)
-Ryan
I can shed all kinds of sarcasm on it!
All ‘can lights’ or recessed ceiling lights have essentially the same rough-in aspects as far as the electronics and can. What you want to be concerned with is the cover you choose for it. They do make covers that are approved for use in steam showers, you need one of those. Vapor and steam will not get through the glass or metal, but it will get through the seams between those as well as around the cover. Make sure to follow the directions.
I know, as guys we have NEVER seen a set of directions for anything – but people tell me most products actually include them. Must be for the ladies.
Roger!
I haven’t received a tip in about 2 months!
What’s going on?
Tip as in: email tips.
Miss your sometimes funny, but usually wise words of wisdom!
Sometimes funny??? I dunno what the hell you’re talkin’ about.
If you have received all 50 tips there will be a brief hiatus. The exact length of this hiatus will be exactly this: until the FloorElf gets off his lazy ass and makes more of ‘em. I’m a slacker, I tend to prefer playing with shiny rocks in showers over writing more tips. 
It is on the list, however, and should resume in about three to four weeks. I just need to find the time.
Workin’ on it.
Roger, I have 2 questions regarding redgard/waterproofing membranes.
First, Would you add fiberglass tape to all corners in a shower in the first layer of redgard? I have seen some websites that recommend this. I know you need to use it around the drain.
Second, we are putting in a stand-alone whirlpool tub, no shower. Should I put any waterproofing on the deck, or maybe just on the front edge of the deck that is more likely to get wet? The deck is 3/4 ply covered by 1/2″ backer board.
Thanks,
John
Hey John,
Yes, you want to use fiberglass mesh tape in the corners to strengthen the membrane and prevent it from cracking or coming apart when your walls expand and contract. It’s there (as well as around the drain and all changes of plane) to strengthen the membrane and assist it to withstand that movement.
Although not required, it is always a good idea to waterproof the horizontal surface of a tub deck. With redgard not only will it waterproof, it will also assist with some movement inherent with tub decks. The tub WILL move, even if it is only the tiniest bit, when you fill it with 300lbs. of water – anything will. It’s always a good idea.
One other question…how durable is redgard to walking on it and ladders standing on it? I would need a ladder in order to reach the wall at the top of the ceiling for 2nd and 3rd coats.
John
Hey John,
On a scale of 1 to 100 the durability for wear resistance would be approximately negative two.
It is not made, in any way, shape or form, to be a wear layer with direct contact at all. You can place sheets of cardboard or something else over it to protect it as you work above it. I use moving blankets when needed.
you shoulda run for president but the voters don’t like people who make sense so you’re doing the right thing thanks for your last reply.Question all wall tiles of bathroom redo installed except for 5 inches remain to end of wall backerboard and gap between backerboard and subfloor varies from nil to almost 3/8 inch. I planto use 1/4″ backerboard on subfloor and 1/4″ tile on that. Not sure whether I should finish wall tiling 5 inches to end of wall backer and try to install 1/4″ floor backerboard an 1/4″ tiles to within 1/4inch of wall and silicone that joint or try to cut the wall backer to allow me to install complete floor under wall overhang which I prefer NOT to do. Please advise
Subfloor
So
Hey Rick,
I’m not batshit enough to run for president.
You can either finish the wall and get your floor substrate and tile to within 1/8″ (not 1/4″ – too big) of the wall or you can install your floor substrate up to the wall substrate (you can leave a gap there, it doesn’t need to go under or butt to your wall), install your floor tile up to 1/8″ of the wall substrate, then finish your walls to within 1/16″ of the floor tile. Whichever you chose you do want to silicone that gap between the wall tile and floor tile.
Hi Roger,
we are getting ready to remodel our master bathroom and I saw “bath crashers” and they used what I think was an epoxy grout (they mixed parts and color together) and then added what I think was finely crushed pebble. I have asked at several tile stores and no one seems to know what I’m talking about. I thought it was a great idea and would love to use it for our bathroom. Any help appreciated. Thanks!
Let me add that I’m talking about our shower floor here
They just poured it once it was mixed.
It was probably Laticrete SpectraLock with dazzle. Dazzle is a component added to spectralock to add metallic flakes, glow in the dark, all sort of interesting stuff. Was it this: Laticrete Dazzle?
Just curious about the shower curb. Previously you have stated that you like to use precast concrete blocks attached with thinset to concrete slab foundations as opposed to just buildng up a curb with lumber. What makes the application of the blocks to the concrete slab different than the installation of deck mud to the slab?…I mean, if the main reason for using deck mud is to combat subsequent movement in the slab up through the installed tile, I understand that completely, but wouldn’t the rigid pre-cast block curb transfer stresses up through the tile installed directly onto it?
Sorry if I went about posing the question in a confusing way
You have the reason for using deck mud over concrete correct, but the use of bricks for the curb has more to do with NOT using wood. Wood will suck in moisture from concrete and swell, when it swells stuff cracks. With the floor you’re talking about a 12 – 15 square foot area (normally), with a curb the amount in contact with the slab is normally a strip less than six inches wide – it would need to crack and move in exactly the right spot to negatively affect the curb, the wood WILL swell, doesn’t matter what size it is.
Hi Roger -
Starting a master bathroom remodel. The floors are porcelain tiles that look like distressed walnut. I will instal two widths (4″ and 8″) in two lengths (24″ an 40″ – both way to long for my tile saw). Majority of cuts are across the width, so easy to cut on my wet saw. My question is the length cuts. Most length cuts are along the wall and will not that visible (under trim). Some are in front of the shower and very visible. Is it best to cut the long cuts with a diamond blade on an angle grinder (dry)? Was going to make a jig to get the cuts as straight as possible. Any suggestions or advise?
Great site!! Thanks for all the help.
-Bill
Hey Bill,
Length cuts are rarely a problem on wet saws, there is nothing to interfere with them. You just want to back up a little.
You can walk the tile into the wet saw, it doesn’t have to be locked in front of the guide/stop on the tray. Think ripping an 8 foot sheet of plywood on a table saw – same method. Angle grinder works as well, it normally will not leave a very clean cut though.
My tile saw is a bridge saw, so 20″ is the max cut (rail supports prevent anything longer). Hoping to avoid buying or renting new equipment. Hoping for an easy answer, but life is not always easy (or cheap)! Thanks!
You know, I was gonna ask if you had a bridge saw but it’s fairly uncommon for someone to have one. My solution isn’t gonna work – but you already knew that.
Your best bet at this point is to use the grinder. Another solution would be to go to HD or someplace else and rent a saw for a day to make all those cuts. You can set all the tiles in the bathroom except the cut ones and get them all marked. You may be able to rent it for only a couple of hours, which is all you really need.
We are about to embark on redoing the tile in our shower/tub and had been planning to tearout the old tiles and install the new ones on the old concrete backer board, which isn’t really that old (15 yrs, maybe) and seems to be in decent shape. Is it ok to do this and expect to end up with a good enough surface for the new tiles? Or should we just plan on ripping out and replacing the old backer board and starting from the studs?
Thanks!
Hi Tim,
It’s always better to start with the studs. You can go over the old stuff as long as the tile comes off of it cleanly and the backer doesn’t tear apart as you take it off. If there are thinset stripes or ridges left over you CAN scrape them off, but it’s a pain in the ass. It’s normally not worth the headache. New stuff is much, much easier. But yeah – you can do it.
Roger,
Thanks for the quick reply, late on a Friday. Your site is amazing and a great source of information. Assuming we can get the old tile off and clean-up the old substrate, would it help to add a fiber membrane, such as Noble WallSeal, or a liquid product like RedGuard? I’m not sure if there’s a vapor barrier between the old backer board and the studs and I don’t want to make a funky situation worse.
Have a great weekend and happy new year!
Once you get the tile off look into the hole around the control valve and you should be able to see whether or not there is a barrier back there. If there isn’t – use one. If there is you can still likely use one, just depends on what shape the barrier is in. If it looks old, use a new one. Anything you may trap in between those barriers is long gone provided you don’t have mold issues or anything like that.
Thanks again Roger. I figured out my original dilemma, with your help. It was impossible to remove the old tiles without pummeling the wall, so we ripped it all out. Fun. But now a couple other issues have cropped up. I came upon DensGuard when looking for backer board at my local big box store and it looked good so I got it. I cut and fit the panels without a problem, no vapor barrier at the studs (none was there before and didn’t add one, as per manufacturer instructions), then taped and mortared the seems, sealed the bottom gap at the tub with silicone, and put RedGuard on the screw holes. I also plan to RedGuard the taped seems. However:
I’ve read conflicting advice on several websites about what type of mortar to use on DensGuard. I bought some pre-mixed, all-purpose thinset for the joints, but read afterward that pre-mixed is, in general, evil, and that one should only use modified thinset or mastic on DensGuard. Any thoughts on exactly what type of mortar to use on DensGuard and does having RedGuard on the seems and screws matter?
The tiled area surrounds the bottom half of a window opening, which I’m replacing with a glass block window, and I think I made a mistake by mortaring and taping the joint between the DensGuard and the wood window jamb. It should have been caulked, right? How bad of a gaffe is this? Should I try to rip out the tape and mortar and caulk or just leave as is and tile over it?
I also plan to tile all of the framing around the window opening, which is a new oak sill on the bottom and wood jambs on the sides and top. How should these wood surfaces be preped for tiles? I was thinking about applying RedGuard all around and tiling right onto that surface. The tiles would butt up right against the glass blocks.
I had to cut two 3.5″ holes for the plumbing fixtures on one of the end panels. How I am supposed to fill in and seal those holes? I tried to use the “cookies” from the keyhole saw and cut and fit them around the pipes and flanges, but that didn’t work. I ended up dropping most of the pieces into the wall, where they will lay forever. Any ideas on how to accomplish this?
Hey Tim,
You can use a regular modified thinset similar to versabond from Home Depot. The redgard makes no difference.
As long as you paint redgard up to and over where you taped and mudded the window. As long as it’s sealed well water cannot get to the tape or mud. The redgard, although not ideal (the wood itself) should work to waterproof the window framing.
You can use tape and thinset (the powdered thinset – throw the pre-mixed stuff away) right up to and around the fixtures to create the substrate, then redgard completely over and up to the pipes.
Hi Roger,
After a couple months working on our bathroom project we’re getting close to finishing, yet I still have a couple more questions regarding grouting and caulking. The more I read about this, the more confused I get.
Grout: The tile store sold us a box of Laticrete Permacolor, in a lovely shade, but the instructions for its use are hard to understand and I get the impression this is tricky stuff to deal with. Should we expect to mix up a single batch and grout all three shower walls in one shot? Its seems this stuff sets up quickly and I worry that we won’t be able to work it into the lines before it sets. Should we plan to mix it in smaller batches, even though we are only dealing with less than 20 sf? Also, how long does Permacolor need to cure? The directions say 3 hours. Does this mean we can use the shower that soon? If not, if the walls were covered by plastic sheets while the grout is curing, could the shower be used? Any other tips about working with Permacolor?
Caulk: My intent is to caulk 1) the inside corners of the shower walls, 2) the vertical line between bullnose and the painted sheetrock wall outside the shower area, 3) the space between the top of the tub and lowest course of tile (about 1/8 to 1/2 inch gap, which is backed by a bead of silicone caulk between the tub and Redguarded DensGuard backer board), and 4) the changes of plane around the glass block window. I’ve already purchased two types of caulk for this job – your standard GE Silicone II in “light gray” and Laticrete acrylic caulk in the exact shade of our Permacolor grout (silver shadow).
After these purchases, I learned that acrylic caulk is generally not the best choice for showers/tubs and that I should have bought something like Latacil caulk, which costs 20 bucks per gun and is not locally available. Given that I think I have a good sealed box behind the tiles, including a silicone caulked joint between the backerboard and tub, should I, 1) go with Laticrete acrylic caulk and enjoy a good color match to the grout, 2) use GE 100% silicone caulk and live with any difference in colors and assume the seal is good, or 3) spring for, and wait for delivery of, Latacil, or a similar product, to get the best color match and best water-proofing performance?
If “none of the above”, is there another product or caulking strategy you can recommend to address my situation?
As always, your advice is highly valued and your time is appreciated….
Tim
Hey Tim,
If you’re worried about being able to grout everything before it sets up just mix smaller batches. You can do it either way. It isn’t really that difficult to work with at all, but I’m probably a hell of a lot faster with grout than you’ll be.
Go ahead and use the laticrete. As long as your shower and everything is waterproofed correctly it’s only there for aesthetic purposes anyway – not waterproofing. Latasil is a better choice simply because it stays pliable longer. Either one will work just fine, though.
hi
Hi
Dave’s not here.
Roger
What tile sealer do you recommend for polished marble in a bathroom. I would like something that will protect it from water stains and if possible, scracthing. I’ve experimented with aqua mix high gloss that I had left over from a previous tile project on a spare piece of polished marble, but it removed some of the shine.
Thanks,
Germain
Hi Germain,
I prefer Miracle Sealant’s 511 Impregnator Pro. It will not change the look or surface of the marble. It will not, however, protect the tile from scratches – no sealer does.
Just found your website while searching for info about tiling by bathroom shower walls and this article saved my butt from creating a “Mold Sandwich”. Thank you for creating this website and I just added it to my bookmarks! Take care!
I think your site is great. I have an issue that has been partially asked but I need the definitive answers so I can move forward on my bathroom(s) remodel. I have two bathrooms that are back to back. I have torn everything down to the studs in one and am installing a new tub and eventually tiling the surrounding three walls. The wife wanted to add some sound dampening between the two showers which are back to back. I thought of using kraft-faced insulation and have read on your site about using rigid foam insulation between a bedroom and bathroom. I have learned from your site that kraft-faced fiberglass insulation needs to be cut to allow moisture to get out. If I use rigid foam should I worry about the “mold sandwich” effect if I use poly as a vapor barrier behind both bathroom substrates (cement board) or redguard as a topical barrier.
Hey Michael,
No problem with that at all. The problem with the paper-faced insulation is that the paper is run over the studs to create a solid barrier which won’t allow vapor to dissipate. The foam insulation is placed between the studs and the combination of the small space between the sides of the foam and not having the studs covered allows vapor to dissipate.
Roger,
I’m preparing the shower for a kerdi wrap and mud-pan floor over a concrete slab. I have searched for local Schluter dealers and have not had much success. Looks like no one in Memphis stocks kerdi. In one of my late night reading sessions, I came across your comment about ordering from one of the box stores, but paying twice the price. What is a realistic price for 108 sq ft roll of kerdi? I’ve seen $189 to over $200. I have looked, but have not seen any supplier recommendations on your site. Some of the search results brought up sites for Schluter, but when you go to the site, you can’t find Schluter for all of the other product the site is offering instead. One site could only sell to specific mid-west states. Is $189 a decent internet price or am I getting a BOHICA price? (Bend Over, Here It Comes Again) Do you ever share or recommend suppliers for Schluter? I’m shopping for all of the Kerdi product for a walk-in shower, including corners, but not drain. Thanks for your help. Time for a cold one!
This is an amazing site. You are an amazing individual to share so much. I’ve been reading your site for about 4 weeks now and keep finding new stuff. If I stop reading, I’ll have to start tiling…and I’m not ready for that yet!
Hey Aaron,
Schluter said BOHICA to all of us by limiting dealers to specific areas with online sales. It really, really pissed me off and is a subject I prefer not to elaborate on. Let’s just say I’m not very happy about it and leave it at that.
Average pricing is about 190-200 for the 108 ft. roll. Don’t know what HD charges for it. I do know that their trim pieces are ridiculous.
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