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.

And the rest . . .

Once you have your entire perimeter done you simply need to pack deck mud into the rest of the base from the perimeter to the drain. Once again – beat the hell out of it. Seriously, pack it in there really well. The more dense your floor is the better. You need to ensure that the line of the floor is straight from the wall to the drain all the way around without any major humps or dips. It takes time and patience – use both. This step is critical since this is the substrate your tile will be installed upon.

Once you get the remainder of the deck mud packed into the shower and have it correctly packed and leveled just let it set for at least 12 hours, 24 would be better. Really, leave it alone. There is something about a freshly packed mud bed that makes people want to pick at it – it’s alluring – and a bit disturbing. But you need to leave it alone. So quit poking at it.

After it sets for about 12 hours you can fine tune it, so to speak, if you need to. Any un-flat spots can be scraped, rubbed, or sanded down to flatten them out. You can use regular sandpaper for this – really. Just make sure you have a flat surface from the wall to the drain. FLAT – not level. You want this surface absolutely flat.

If you have not yet done so you can now install your moisture barrier and backerboards. Now that you have a large waterproof box you are ready to install your tile and make it look all pretty. The hard part is finished. As with any proper tile installation the underlying substrates are the most important. Take your time with the preparation, it is imperative. Without proper preparation any tile installation is doomed to fail.

And your dog may burst into flames.

Well now we’re ready to waterproof your curb. If you have reached this post before reading the previous two, start with How to build a shower floor from the beginning.  Now that you’re ready to get the curb cut and waterproofed lets get it done.

And yes, I know my pictures suck – I’m a tile guy for cryin’ out loud, not a professional photographer. Until you try to balance a liner, a razor knife, a margin trowel, and a camera while trying to take a photo don’t give me any crap about it. Oh, and you can click on any of the images for a full-size version – partake in the full glory of how much my photography sucks.

We need to start by finding the inside lower corner of your shower pan and making certain that the liner is pressed firmly against it. Then follow it up the corner of the curb and wall to the top inside corner of your curb. This is the spot at which you will start the cut in your liner.

Cutting a liner for a curb when shower walls will be backerboard Click to Enlarge

Deciding in which direction to make your cut depends upon how you plan to waterproof the walls. If you are simply using a cementious backerboard on your walls with a moisture barrier behind it you want to cut from that point straight up. Or, more precisely, cut your liner so that when it is placed flat against the studs the cut will go straight up from that point.

If, however, you are using a topical waterproofing membrane (that’s just fancy-ass, pinkie in the air talk for waterproofing that goes right behind the tile) I cut it a bit differently. Start from the inside top corner of the curb and cut straight out to the outside corner of the curb.

Cutting a liner for curb when using a topical membrane

The reason for this is simple – to me anyway – if you are using a cement backerboard or any type of substrate where moisture will get behind your wall, you want to have as much of a liner at the ends of the curbs as possible to run up the wall. With a topical membrane such as Schluter Kerdi or a liquid such as Redgard you don’t have to worry about that. By the time any water behind the tile gets to the bottom of your waterproofing it should be well below your curb – provided you’ve installed it correctly.

On the inside corner of the curb you should install a ‘dam corner’. These are pre-formed outside corners which are glued to the liner to cover the spot where you’ve made the cut. I do not have a picture of these because I don’t use them, I’m a hypocritical bastard like that. But you should. (Use the dam corners, not be a hypocritical bastard.)

When you do glue your dam corners in you need to make sure you use the correct type of glue. Just like drain pipes – pvc glue for pvc liners and cpe glue for cpe liners. The glue WILL NOT work the other way around. Really, don’t try it, it’s an expensive lesson. Take my word for it.

The liner gets wrapped over the top of the curb

Now that you have the ends of the curb cut we need to move on to preparing the curb for tile. Take your 2 x 4 that you used to level your pre-slope perimeter (you did that, right?) and place it in the inside corner of your liner against the curb and the floor. This ensures that the liner lies completely against the floor and the curb without air pockets or empty space beneath it. Then nail the OUTSIDE of your liner to the curb – only the outside, never the inside.

Please note: these photos were taken after my final mud bed was in place. I installed the curb last on this particular project. You can do it before or after your final mud bed is fabricated. Dealer’s choice.

Nailed only on the outside of the curb

To hold the liner in place over the top of the curb you need some metal lathe. Provided your curb consists of three 2 x 4′s your lathe needs to be cut into strips sized to fit over your curb from the floor on the outside to the inside bottom corner of your shower. Bend the lathe into a ‘U’ shape (length-wise) and place it over the top of your liner over your curb. Something else I do not have a photo of. Just because I’ve never taken one, not because I do it differently.

You only need to nail the liner on the outside if you have a wooden curb. If your shower is on a concrete subfloor you used bricks for your curb – right? Pay attention, if you fail the quiz later you owe me a beer Pepsi.

I have one more photo for this post and this is it. Isn’t that spectacular? It’s just to show you how I do the ends of the curb when using Kerdi on the walls. “But why don’t you use Kerdi on the floor too?” Glad you asked. It’s a very technical answer and requires you pay attention to every part of it or you may get lost in all the details. Ready? Because some people don’t wanna pay over 100 dollars for a shower drain. Whaddya gonna do?

Shower pan liner on the end of the curb.

Couple of things I’d like to point out about that last photo before you go bustin’ my chops too hard. First, the excess liner is not yet cut out. I cut it straight down the edge of the drywall there and everything gets tucked straight back into the wall. Secondly, yes, I put a nail through the liner. A foot above the curb. You can light it on fire that high if you choose to do so. (I wouldn’t recommend that, though. And no, I don’t want to talk type about it.)

Now we have to water test your pan to make sure it does not leak. Note: most cities and counties REQUIRE this to be done – don’t skip it. The test simply ensures that all your hard work is indeed correct and your pan does not leak. That’s it.

You need to plug the drain (or you’ll be there all night trying to get enough water into it) which you can do with either a $75 specialty plug, or a water balloon. You pick. You need to make absolutely sure that (and I’m assuming you chose the balloon option) the balloon is pushed far enough down into the drain to block the weep holes as well.  If they are not it will let you know that your weep holes work correctly. Unfortunately it does nothing to reassure you about the liner. If you look carefully into the drain you should be able to see the holes for the weep holes, get below them with your plug.

Then just fill ‘er up. All the way up to just a hair below the top of the curb. (take the 2 x 4 out of it first if it’s still in there) and leave it set for 24 hours. After the 24 hours have elapsed and you are reasonably recovered from your recently induced hangover, check to make sure the level of the water has not gone down. If it hasn’t you are ready to go.

Now if we could just get that elf guy off his ass to write the next post you will learn how to fabricate your final mud bed and tile that sucker. Hang tight, we’ll go get him. Check back real soon, y’all. And as always, if you have any questions at all please feel free to use the comment section below.