So here’s today’s question: How do you waterproof a curbless shower in a basement bathroom? If you watched our prior videos in this series, we showed you how to build up the curbless shower pan using a 4 to 1 Mud Mix. The next step after that is to waterproof it. So we ended up using a liquid waterproofing membrane made by KBRS. And in today’s video, we’re going to show you some tips on how to do that.Okay, so to waterproof this shower, all the cement board and our channel drain, we’re going to use the KBRS liquid waterproofing membrane. It’s basically just a liquid membrane you apply with a brush and a roller, and it comes with this mesh that we’re going to seal all the seams of the concrete board, the corners, and all around the edging over the shower floor. So first thing is I would precut all my pieces so that you’re not fooling around with this once you start applying the membrane. Yeah, just basically get these precut. Okay, so first thing, if you’re using Wonder Board, get all this tape off of here. I don’t know why they do that, but you want to get all that paper off of there. Okay, so you do want to just wipe up any dust or anything off of your shower pan. You don’t want to saturate it with water, but you do want to wipe everything down a little bit with a damp rag or a damp sponge.And then we’ll stir this up a little bit. Okay, and then with a four-inch brush, we’re going to go ahead and do these corners first. So apply a generous amount in the corners here. Even when you fold it, just make sure you have sealant underneath it when you fold it. So you just want to try and make this as tight as possible, just pushing the brush in and adhering that mesh on there. Doesn’t really matter which way you fold it. You can fold it on the wall, you can fold it on the pan side. But just try to keep everything tight to make tiling easier. So I just want to try and keep this half and half. Once again, just a little… put some sealant under there. Fold that out. Now I do have a pretty decent size gap here on my cement board, and technically I should probably cover that in a little bit more, but we’ll get that covered in anyways.So we’ll go ahead and put our back mesh and bond it to the flange. So we’re just getting this attached to the flange and trying to get like a two-inch overlap on either side. I would wipe anything out of this drain; they might be able to see that at
some point. Okay, on this outside corner, we’ll get all this foam out of here that we had for the underlayment. What we’re going to do like an outside corner here. And this is a pretty critical area. I would definitely… because this is a curbless shower, you want to make sure it is sealed around either side here.So we’re going to do this in a couple of parts here in order to get this to fold around. Okay. I would definitely be generous with around that corner. So as you can see here, we continue to smooth out the liquid waterproofing that’s going over the fleece. What’s important here is you’ll see Steve is smoothing out any wrinkles in the fleece, and you definitely want to do that because the wrinkles could adversely affect your tiling. So here we’re just making a slice in the fleece. Sometimes it pulls the fleece from the wall, but don’t get frustrated by that. As you can see, it happened to Steve there. Just continue to move forward. And the reason we cut that slit in the fleece—and we’re smoothing it out again—but the reason why we cut that is the fleece will roll over the additional waterproofing that we put in the corner there, the additional fleece that we have in the corner.So just know that additional waterproofing in the corner, not a big deal. Definitely want that. Same thing here, get rid of our backer right here. So again, we’re applying the liquid waterproofing to this outside wall—that’s outside the shower that is—and we’re adding out fleece to it. Again, you want to apply a copious amount of the liquid waterproofing. We’re just cutting a slit in the fleece so that it relieves that pressure point that’s going around the outside corner, and it’ll allow you to actually adhere the fleece without having additional wrinkles down on the floor or on the wall. So again, you just need the make that slit there. And then you just apply additional waterproofing, and you can add another piece of fleece, like we did on the other wall in there, and you just cut a relief cut in there, and it’ll fold down.So again, you can actually do this dry; you can kind of dry fit it, unlike we did here. And that way you don’t have to have it be a little bit messy than the job that we did. Nonetheless, that flap folds over into the shower, and that gives you extra waterproofing. So again, we’re just applying our liquid waterproofing to the back wall there. And
then we’ll apply our fleece. And as you can see here, you want the fleece to be evenly embedded in the cement board and the shower pan. And so, again, try to evenly split the difference between the cement board and the shower pan. Then you can embed it using the liquid waterproofing. So now we’re just applying the liquid waterproofing to the inside corner inside the shower. Again, embed your fleece evenly in that corner. And it’s nice, as we said at the beginning, to have all these precut to help with the installation process. So again as you’re doing this, the biggest tip that we can give to you is apply generous amounts of liquid waterproofing in the corner before you add the fleece. And then as you’re adding the waterproofing over top of the fleece, to smooth out any wrinkles that form.And the reason why is, again, it could adversely affect your tile setting. So if you have a wrinkle in the fleece, it could bump out the tile. And that’s why you want to constantly check, like Steve is doing here, any of the wrinkles and to smooth them out with a paintbrush or even with a three-inch putty knife; that does come in handy, although we didn’t use it on this particular project. So taking your time and really paying attention to how much liquid waterproofing you’re adding is super important.Again, this is just our first coat. And we did a second coat over top of all of this. But the most important thing to do here is to just completely embed the fleece on all the seams. So this is a horizontal seam between two adjacent cement boards, and we’re just filling that in with the liquid waterproofing like we did in the corners, and then adding the fleece over top of it and smoothing out the fleece itself.You’ll have a little bit of a bump there in the center where the two boards meet, but that’s not a big deal. And actually you just want to try to smooth that out, as I said, as much as possible. And then this is the main wall. And I believe we have two horizontal sections there. So again, we’re just going to fill that in with the liquid waterproofing and the corresponding fleece. It’s pretty easy to do, and you can see there’s just a pattern to it. You want to fill in all your corners and all your seams with the fleece, and then you can go over the screws, as we’ll show you how to do here in a second.But again, there’s a pattern to it, and it really is just working
with the fleece first and then filling in everything else after that. And then I would just dab all your screw holes with a brush because a roller isn’t really going to get into that too well. And obviously, a brush you can really get it in there. And then on this corner bead, I would put some mesh along this as well to protect it and keep it from any moisture that would be sucked in from the thinset because water will eventually get through the grout joints at some point; you can’t rely on grout joints on your tile for any type of waterproofing.But if water does get in below that then the thinset layer really likes to suck it in. So you want to make sure that this metal is all waterproofed at this level so that any moisture won’t rot that out. And a lot of this corner bead stuff it’s really cheap metal, so it doesn’t take long for it to rust. So cover it with the waterproofing to ensure it doesn’t do that. Same thing goes for any of the fleece that goes over top of those corner beads. Just fill in over top of the corner bead with your liquid waterproofing. Apply a generous amount. Add your fleece, and smooth out the fleece like you did for the corners and the horizontal seams for the shower. So, like Steve said, this is really important to fill that in to protect the corner bead so that it doesn’t rust out if you used a metal corner bead. Now, we’re just filling in all the screw holes on this back wall using the paintbrush. And we actually decided to cut two little square pieces here and to fill in even more with the fleece in the corner so that it slightly overlaps the linear drain there.So we’re tying everything into the linear drain and ensuring a really nice layer of waterproofing in the corners. That’s where you can potentially see a leak in this shower even though we built up the corners, and it’s obviously level, and everything’s draining toward the linear drain, it doesn’t hurt to have additional waterproofing in the corner. And that build up will in fact help you with the drainage into the linear drain.So there’s really no worry about that extra build up. Then just use a three-eighths inch nap roller to roll on additional liquid waterproofing onto the cement board. So again, in this case we’re doing it all in the vertical. You want to try as much as possible to roll it on vertically. Here, we’re trying to avoid getting any of the waterproofing on the
ceiling, so that’s why we’re rolling it on horizontally.But your first coat should all be in one direction. In this example, it should try to be all vertical. And then when you put your second coat on, you can go all horizontal. And the reason for that is to fill in any of the pores. So again, we’re using a paintbrush to go around our shower valve there and the mixing valve in the center of the shower.So anywhere where you have a mixing valve or little tiny spots where you have to fill in, you can use a paintbrush. I’m going to have also just between this mud and the concrete floor outside. I’m actually just going to put a piece of fabric there. And really I guess that’s just because since it’s concrete here and the mud bed here, I feel that this will isolate some cracking potentially and just kind of reinforce the waterproofing on this part. Because if anything did like shrink on the concrete side and it becomes a gap, I could see that just the liquid membrane itself not being enough to handle that. And now I’m just going to go ahead, since this is a little bit rough, I’m just going to brush in the whole shower floor and making sure that it gets a good bond. This waterproofing on the entire outside of the floor, this is also considered an isolation membrane. So this will kind of basically separate the concrete from the tile installation and provide a little bit of a little crack isolation from the concrete.So rather than using DITRA or anything like that, we’re just going to use this as an all-in-one deal. But I would definitely consider and go ahead and seal against the dry wall. Put another corner piece here and go along the entire edge. Not all the entire room but at least for the first three feet. I’m going to go and do this entire area here, but this is a critical area too. And only because it’s curbless, any water that might migrate out of the shower for any reason, that’s a good idea to have it sealed. So this is definitely just a preference thing that I like to do, but it’s by no means absolutely necessary. So we’re filling in on the main floor here. And as Steve stated, it’s really important to add the fleece to the corners. This simply protects any water that might leak out of the shower. So we’re doing this on all of the walls within the bathroom. And the nice thing is the liquid waterproofing membrane from KBRS is an isolation membrane, so it’s
serving the same purpose as a DITRA product or a DITRA Heat, and it’s helping to prevent your tiles from cracking when they’re set on top of that concrete floor.So the inside corner here we’re adding fleece, just like we did inside the shower, and then we’re going to fill in all of the floor using the liquid waterproofing membrane. So again, we’re just kind of filling in around pipe coming out of the floor for the toilet there—you can use a paintbrush for that—and rolling on the rest of the waterproofing using that three-eighths inch nap roller and working out of the bathroom in that direction. So there you go. That’s how you waterproof a concrete curbless shower. Our biggest tip for a curbless shower is to ensure that the entire bathroom floor is waterproof. And that’s why we used the KBRS liquid waterproofing membrane over top the entire floor. Now, in our next video we’re going to give you tips on how to start the tiling process. So keep an eye out for that. In the meantime, if you are remodeling your bathroom and you want our help, get our free guide right here. It’s awesome. We show you how to plan a bathroom remodel in ten days or less.Really great video tutorials. We’ll walk you through a lot of different things step-by-step. So you can get the guide right here. Check it out for yourself, and we know that you’ll love it. Thanks for watching today’s video, and we’ll see you in the next one. Take care! .