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.

Another request from one of my readers, this time concerning weep holes. As you may know I answer every question I’m asked here on my site when I sober up get home from work. I have tried to explain in the comments section several times where to create weep holes in a tub or shower (acrylic base) tile installation and now realize it’s a difficult thing to do with words.

So when Kurt asked me to clarify exactly where they go a stroke of genius hit me! (Yeah, I’m slow sometimes) I have pictures. Well, not exactly pictures of the weep holes themselves, but I can at least let you know where they are.

When you have a tub which does not have specific spaces for a weep hole you need to ‘create’ them in your caulk line. Let me back up here a second and explain what weep holes are and why you need them.

A weep hole is basically an open space which allows moisture that makes its way behind the tile a space from which to dissipate. This is the spot that moisture can run out. When moisture gets behind your tile it will always end up at the bottom of your wall (tile installation). When it gets there it needs some place to go – to get out from behind the tile and into the tub or shower basin. That’s what the weep hole is.

Some tubs, and most acrylic shower basins, have these built into them. There is a spot about 3/4″ long that dips down from the plane of the edge and back up. It’s a dip in the edge of the tub or shower basin. When equipped with these built-in weep holes – DO NOT FILL THEM WITH CAULK! Everyone does that – they are there for a reason and no one seems to know what it is. They are weep holes. If you caulk them in it defeats the purpose of them – that will seal in the moisture.

If the moisture is sealed in behind the tile it has no place to dissipate and will simply sit there. Beyond that, the level of that moisture will continue to build with every use. The moisture cannot dissipate at the same rate that is gets back there. That’s gonna lead to a problem. You need weep holes to eliminate the moisture.

When you caulk or silicone the change of plane between the tile and tub you should leave an open space – a space without caulk – in each side wall about an inch out from the back wall. If you click on that little bitty picture to the right you will see two pretty pink lines on it – that’s where those spots are.

Each of these spots are about an inch long (this doesn’t need to be exact) and contain no grout, caulk or silicone – they are simply open space. These are your weep holes.

These spaces will allow moisture to dissipate. These do not need to be the lowest spots on the tub. In other words, if your tub is not entirely level and those spots are not the lowest, it doesn’t matter. The water will end up there and run out – it is the only space to release the pressure the water will build up. It’s a whole physics thing and I haven’t had enough beer Pepsi to properly explain it – but that’s what happens. And yes, you can put them wherever you want, that’s simply where I put them.

When you have an acrylic or fiberglass shower basin without built-in weep holes the same technique applies. Depending on how your tile and shower door lay out you may choose to put the weep holes toward the front of the basin, entirely up to you.

If you click the photo of the shower to the right, and ignore the fuzzy toilet seat cover,  you will see the two pretty pink lines in the back as well as pretty blue lines toward the front. That’s where I put them when I don’t put them in the back. They sometimes look better toward the front if there is a shower door there – the frame will make the weep holes less noticeable.

That’s it – longer than I expected but much easier than trying to explain with just words. If you have a question or just need something clarified do not hesitate to let me know! My blog is here to help you and the fact that I do this stuff every day will, at times, blind me to certain basic things. I do a lot of this stuff without even thinking about it and don’t realize that what is basic to me is not basic to you. If you want a post about a specific subject just let me know in the comment section of any of my posts or shoot me an email at Roger@FloorElf.com. Or, you know, send up smoke signals from your dogs back – he may have just burst into flames again.

There you go Kurt, tell mom you win this one and she owes you a six-pack.

UPDATE: I finally got off my ass and actually took some photos of weep holes in the silicone bead around a tub. These are what I’ve described above and can be used in either a tub or a shower base. There is one on each side of the tub towards the front.

Michael has recently pointed out (a bit more eloquently than I would have) that I have indeed been a lazy bastard and have not yet written this post. Apparently people actually want to know how to do stuff I do – weird, right? So here you go – making your ceiling shiny.

The main problem people have with tiling a ceiling is getting the tile to stay where they put it. Believe me, I’ve had more than one tile fall on my noggin before I figured out what works. Since I’m relatively certain you aren’t very interested in what doesn’t work I’ll tell you what does, it saves headaches – literally.

You do not need a $75 bag of non-sag thinset to tile a ceiling. Non-sag thinset is basically just thinset that is sticky – it’s great stuff! It’s also expensive stuff. You can accomplish the same with the $15 bag of regular modified thinset.

Before you start hanging head-bashers (ceiling tile) you should, as always, have the substrate properly prepared. They do not always need to be waterproof. It’s a good idea and never hurts, but it isn’t always necessary. The photos of the shower I have here was in a small bathroom with limited ventilation so I waterproofed the ceiling as well.

Photo 1

You should always ensure that the ceiling substrate is screwed onto the joists securely. There is a whole different set of physics at work on a horizontal surface that don’t apply to your vertical wall tile. Basically the entire weight of the full tile is pulling constantly on every inch of your tile. So you want whatever it is attached to securely fastened.

Photo 2

Photo 3

The first thing we’re gonna do is burn your thinset into the ceiling substrate – in this case it’s Kerdi. ‘Burning’ thinset into something simply means using the flat side of your trowel and skim-coating the surface. I use the term a lot and that’s all it means. It fills all the areas of your substrate or tile (whatever you’re burning it into) and ensures that your thinset gets a good grab on whatever it is. Photo 1 shows about half of the ceiling with thinset burned into it.

Photo 4

Photo 2 shows the back of one of the tiles we’re installing on the ceiling. See all those white lines? Those are actually raised just the tiniest bit so the back of the tile is not entirely smooth. You need to burn thinset onto the back of the tile. This will fill all those little squares and ensure that you have every area on the back of your tile adhering to thinset. You want to give it every square inch possible to grab onto that ceiling. Photos 3 and 4 show the tile with thinset burned into the back.

Photo 5

Now you want to flip your trowel over and comb thinset onto the back of the tile. “Combing” thinset is another term I use often – it just means using the notched side of your trowel to, well, comb the little lines all in the same direction. That is – wait for it – Photo 5. You are not allowed to give me crap about my lack of photo labeling originality!

Photo 6

Now we get to the secret ingredient of ceiling tile installation – suction! All that thinset you combed into pretty little lines on the back of your tile? Take the end of your trowel and draw a bulls-eye in it like Photo 6 (believe it or not I was totally sober when I drew that ‘circle’). This bulls-eye is what keeps the tile from dropping on your head – because that hurts like hell. You should just take my word for it on that one without testing it for yourself.

Photo 7

Now that you have your bulls-eye on the back of your tile go ahead and press it up onto your ceiling. (Photo 7) You want to push hard! You will actually hear air squishing out from inside that circle of thinset. This creates suction on the back of your tile and helps the tile stay put until the thinset cures. Once that happens it doesn’t matter what shape your thinset is on the back. The suction is needed to keep it there only until the thinset is cured.

Photo 8

Continue to do this with the rest of your ceiling tile – every one of them, even the cut tiles. Draw the bulls-eye and stick it up, draw the bulls-eye and stick it up, etc., etc. To get them to stay in the proper spot with correct grout line size and lined up you can actually stick spacers in them (Photo 8 ) and use blue painter’s tape to keep them in the proper spot relative to one another. Just get a piece of tape about 3 -4 inches long and stick half of it to one tile then pull that tile slightly toward the one next to it and stick the tape to the next one. This will keep each tile tightly against the spacer and the tile next to it so your grout lines don’t go all wonky. (Did I just type ‘wonky’??? Jesus…)

You do not need to comb thinset onto the ceiling. I know that sounds counter-intuitive but simply burning the thinset into the substrate will give you plenty of grab onto the tile. You do not need to be concerned with 100% support as you would on a floor – no one will walk on your ceiling except Spiderman – he’s an ass sometimes. But he always pays to replace any ceiling tile he cracks.

Once you get all your tile up there you can still push them upward to get them flat with each other. Just lay your straight-edge across them as you would on a floor and make any adjustments needed. You do not want to pull them down to adjust them! You will lose the suction doing this. You want them really close to flat before you make any final adjustments.

Photo 9

You can see in Photo 9 (if you click on it) that there are two tiles that have slightly low corners which I still need to push up (they’re in the back row – the left corner of tile two and the entire front edge of tile four). Always push up to make adjustments. If your tile is way out of whack pull it down as you are setting them to add or take away thinset on the back. Do not pull them down once you have them all set and taped.

That’s it. That’s how you get tile to stick on the ceiling with regular thinset. Easy. Okay, it’s easy for me. You may have a bit of a learning curve.

There are two basic designs for your ceiling tile. You can either line up all the grout lines (which requires planning!) or you can install the ceiling tile on-point (diagonally). This is simply a personal preference – whichever you think would look better in your shower is the one you should choose. The photos here have all the grout lines lined up. If you do not install your ceiling tile diagonally please line up your grout lines. If you don’t it looks like crap – that simple.

When installing tile on the ceiling you want to install the tile on the shower walls all the way up to the last row before the ceiling – as I’ve done in these photos. If you are lining up your grout lines rather than installing them diagonally you can then draw lines on your ceiling as guides to where your tiles should be. You don’t see lines in these photos because I use a laser – I’m Star Wars-ey like that.

Once you get all your ceiling tile up then install your last row of wall tile. This will help hold all the tile around the edges as well. Be sure not to cut the last row of wall tile so that it barely fits in there! You need an expansion joint of about 1/16″ and you do not want the pressure of a wall tile that is not short enough pushing one side of the ceiling tile up – the other side will push down – leverage, you know. Cut them about 1/16″ shorter (plus your regular grout line size for the line below it)  than your measurement and use plastic wedges for that gap. And when you are finished – caulk or silicone that space, don’t grout it (unless you’re using epoxy grout).

The thinset I’m using is a basic modified thinset – nothing special. It’s Versabond which is commonly sold at Home Depot. You should know this, just to avoid confusion about an issue that is confusing enough anyway. Schluter recommends UNmodified thinset for the Kerdi membrane. If you choose to use modified thinset over the kerdi membrane it will void your warranty! Just be aware of that.

I use modified for two reasons: 1) I prefer modified thinset for everything – period. I give my own warranty to my customers which happens to be longer than Schluter’s warranty anyway. I take that risk and choose to do so – consciously. Should you choose to use modified thinset over kerdi you should be aware of this. And no – it does not create any problems that I have ever been aware of. Doesn’t mean it won’t, just means I have never heard of it. And 2) I’m a rebel like that.

If you have any questions at all please feel free to leave a comment and ask there – I’ll respond when I sober up! The gist of this post was shrunk down into a handy little four paragraph email for TileTips. You can click that link for more information or simply sign up in the box at the top right (under the pretty picture).

This post was brought to life by the suggestion of one of my readers in a comment. I really do read them! So I would like to thank Michael for kicking me in the ass and making me do something productive! My wife thanks you, too. If there is a particular subject you would like to see a post about just let me know – I’m a wealth of useless information.