Now that you have your curb built and your pre-slope done (if you haven’t done this yet check out How to create a shower floor, Part 1) you are ready to install your waterproof liner.
Purchasing a waterproof liner
When you order or buy your liner you need to get one large enough for your shower. The liner you get has to be at least one additional foot larger than each of your measurements. For instance, if your shower floor is three feet by five feet your liner needs to be four feet by six feet. This allows enough to run the liner up the wall behind your backerboard six inches each way. You also want to purchase two “outside” corners for your curb. These are pre-formed corner pieces to waterproof the ends of your curb after you cut the liner.
I usually order mine two feet larger in each direction. Six inches is the minimum. Specifications state that your liner must run up the wall at least three inches above your curb. So if your curb is three inches high your liner needs to run at least six inches up each wall. I usually go a foot above the curb – overbuilding your shower is rarely a bad thing.
Preparing your shower floor for a waterproof liner
It's supposed to be sandy!
Before you install your liner I need to say type this: your preslope will be sandy, it’s suppose to be sandy – it’s normal, don’t panic. If you have any high areas in your preslope you may want to scrape or sand it down so it runs in a flat, straight line from the wall to the drain. Notice I said typed “flat, straight” and not level – if it’s level water won’t drain.
You can scrape it down with a regular razor scraper or sandpaper – yes, sandpaper. If there is a significantly large dip in your pre-slope you can fill it with more deck mud. You’ll need to coat the pre-slope with thinset under the patch to ensure it will stay put. Don’t get all OCD about this, it doesn’t have to be perfect. Just make sure there are no major humps or dips and water will run from the wall to the drain without problems.
The next thing to do is take a chisel to your wall studs. You weren’t expecting that, were you? You want to notch out your studs about 1/8″ up to the height of the top of your liner. This is so you can place your backerboard over the front of your liner on the wall without them jutting out at the bottom. It allows your walls to remain flat all the way down to the shower floor. You will create “cavities” in your wall studs for the liner. 1/8″ is a bit larger than the thickness of your liner but it’s better to be larger than smaller.
When you place your liner in the shower you will be folding the corners so you want to allow enough room on one of the corner studs for three layers of the liner. I usually notch my corner studs out 1/4″. This allows enough to keep your corner square after the walls are up.
Placing the liner in your shower
Liner placed over pre-slope
Now it’s time to lay your liner in the shower and get it all lined up. DO NOT cut anything until you have the liner exactly where you want it. Make sure you have the top half of the drain flange removed before you place your liner over it. I’m not talking typing about the round part that unscrews, I mean the top half of the lower part which bolts onto the lower half. After removing the top half of the flange replace the bolts, this will serve as a guide when you cut the liner.
Center your liner in the shower with the ends running up the walls evenly. Also make certain you have enough of the liner draped over your curb so that you can attach it on the outside of the curb. I will usually place it so that the liner drapes up and over the curb all the way to the floor on the outside of the shower.
Cutting the hole for the drain out of your shower liner
Drain hole cut out of liner
After you have it properly positioned you can cut out the hole for your drain. Do this very carefully – there is no second chance. Take your utility knife and poke a hole through the liner directly in the center of the drain. From there cut in a circular motion toward the outside of the drain in a spiral. Only cut it out to the outside of the four bolts which attach the top half of the flange to the bottom.
Silicone under the liner around the drain
Remove the bolts from the flange. Now you need to place a bead of silicone under the liner around the perimeter of the lower flange. The easiest way to do this is to place the nozzle of the tube of silicone into the hole you just cut for the drain. Place a good size bead around the lower flange outside of the bolt holes, don’t get any in the bolt holes. This prevents any minute amount of moisture from getting under you waterproof liner. Press the liner into the bead of silicone all the way around the drain to ensure full contact.
Prepared liner ready for top slope
Now you can bolt the upper half of the flange to the lower. Do not overtighten the bolts. You want to squeeze the liner between the two but not so much as to crack the flange – they are only plastic, after all. That’s it, the drain is finished.
Now take your liner and place it up the walls into the notches you cut out of the studs. You can nail or tape the top of them to hold them in place. Only place one nail into the very top of the liner, never lower. In the corner you will fold the liner over on itself, never cut it. Place the folded part into the larger notches. There should be enough room in the notches so your backerboard will set flush onto the studs.
In my next post I will cover how to cut the liner for your curb and make sure it’s waterproofed properly.
Never mind roger I have read this section about six times now I think I have found my answer. Consistent slope from edge to drain. Mirrored by same measurement at drain as walls. Straight line from wall to drain
Okay.
That’s correct.
Roger,
Steve here and I am reading your traditional floor topical wall book and am putting my top coat on after 24hr water leak test. Confused about what I am reading you state the top coat should be level from the wall to the drain. ( meaning no slope) then I also read a consistent even amount of topcoat which you indicated 3/4 in. Is what you prefer or try to do. That would indicate it mirrors the preslope in my mind ( slopes) Don’t want to do rework if I don’t have to.
Hi Steve,
What I mean is that your top deck should be a uniform thickness from your wall to the drain. It mirrors the top of your preslope.
Hi Roger,
I am ready to lay the deck mud over the membrane. The membrane extends
seven inches up the studs and is attached with staples 1/2 inch below the
top edge. After I do the top deck mud I will install the wonder board on the
walls from the ceiling to top of mud deck. My question is what retains the
wonder board to the studs in the bottom seven inches where the membrane is and how much should the final gap between wall tile and floor tile be?
Hi Larry,
You can either notch your studs to tuck the liner inside of them so you get a flat plane all the way down the wall, or shim the studs above the liner to accomplish the same thing. Gap between wall and floor tile should be 1/16″ – 1/8″.
Two issues: My plumber laid my slope on concrete without using thin set as a base. OK?
Second, he forgot to put plumbers puddy or a bead of silicone between the drain and the drain top plate. OK?
Tks Jim
Hi Jim,
1. Yes, you simply have an unbonded mud bed, completely fine.
2. Nothing goes between the drain and the top plate. Silicone between the lower flange and the liner is ideal, but not absolutely required. The liner will squeeze and seal as the bolts are tightened.
Mucho gracia. I feel better already.
One other issue – the curb. Mine is concrete with the liner lapped over it as you indicate is correct. While there is a mud bed over the shower base on which I can put thinset/tile, what do I do on the inside/top/outside of the curb to prepare the liner for tile?
Thanks and regards
Jim
Use wet mud.
Hi Jim,
Yes, you simply have an unbonded mud bed. You never use plumbers putty there, although there should be a bead of silicone between the drain base (lower flange) and the membrane – not sure what you mean by the drain and top plate.
Without going into too much detail why, lets just start with where I am. I screwed the cement backerboard to the studs and then built the pre-slope because I wasn’t planning on using a liner. I was going to use Redgard on top of the deck Mud and then start laying tile. However, I screwed up the installation of the bottom flange of the drain and now the drain is sticking up a couple inches higher than it should.
So my question is, should I abandon the topical liquid waterproofing method and go with a traditional liner, or should I skip the liner and just lay more deck mud until its where it needs to be, apply the Redgard and then lay the tile as I planned? From what I have read on your site the liner is supposed to go behind the backerboard. Since my backerboard is already behind my pre-slope am I in too deep to change methods now? And if so, should I apply the Redgard on the pre-slope and then lay more deck mud to finish the floor, or should I just build up the floor with another layer of deck mud and then apply Redgard to the top?
Hi Kelly,
Your easiest option is to paint the redgard on the floor and up the walls. Just treat it as one large liner from the drain to the top of your shower. Once that’s cured you can just place a second mud deck over the floor up the height you need and tile away. It is and approved method, by the way.
Hello, Shower wall to mud bed. I have Dens shield tile backer board, is it OK to use this for the walls before the second mud bed is aplyed or does it need to be duro rock?
Thanks in advance.
BB
Hi BB,
It’s fine for the walls, but it needs to be 1/4″ above your top mud deck, it can not be embedded in the mud.
When you cut out around the holes in the drain do you also notch out the area covering the weep holes?
Hi John,
No. The weep holes lie above the liner, the liner needs to be below them sandwiched between the upper and lower flange.
I don’t understand how water escapes thru the weep holes if they are blocked to the drain by the membrane.
Hi John,
How are they blocked by the membrane? If they are you are doing something incorrectly.
Looking at my drain assembly the weep holes are back by the bolt holes. If I cut a circle in the membrane using the second piece opf the drain assembly that has the bolt holes as a guide there will be membrane covering the weep holes. If I cut the hole using the flange in the floor as my guide I would be clearing the weep holes. Most every picture I see shows a circle cut with the second piece as the guide. I don’t know if this makes sense but it still confuses me.
Your weep holes are ABOVE the membrane. Anything you cut under the membrane isn’t going to affect the weep holes. While the weep holes themselves may be outside the cut area of the membrane around the bolts, once water gets into them it is channeled between the weep holes and membrane into the center of the drain. The only way you would affect the weep holes with your membrane cut is if they were in the bottom flange – they aren’t.
Roger
After doing the pre-slope with deck-mud as described on your site, I then laid down the membrane and did the overnight water test which was fine as far as no leaks. I then drained the water and found a small pool of un-drained water to the left of the offset drain. I proceeded to install the bottom half of Durock around the 3 walls. Now I am having second thoughts about that water pool…..what should I do?
Hi Bob,
A small ‘bird-bath’ in your preslope isn’t going to affect anything at all. If you want to remove one of those boards and get under there with some thinset to flatten it out you can do that. But if you want to just go ahead and do your top mud deck it’ll be fine.
Thank you Roger, I appreciate your time and knowledge.
So just to make sure I have this right: after laying the mud bed, it needs to dry for 72 hours before laying a thinset slurry for the Redgard to attach to? How long does the thinset slurry need to dry before applying Redgard?
Hi Matt,
24 hours. You can paint the redgard directly onto the cured mud bed if you want, the thinset just makes it easier. It’s not necessary.
Hey Roger,
If I am wanting to use Redgard as my liner, how long do I need to let the pre slope dry before I can apply the Redgard? Thanks
Hi Matt,
Three full days.
Hi Roger.
At the risk of turning you into a broken record I have the following question/clarification for you:
Tile guy did a deck mud preslope to the drain flange.
Hot moppers came in and tarred the preslope as well as 6 inches up the walls.
Tile guy came back in and floated a mortar bed on top of the hot mop as a base for our linear drain. The only thing left now is the tile and thinset mortar.
Should I resist the urge to Redgard the mortar bed before he installs the tile and thinset finish work?
If I applied Redgard it would mean that the mortar bed has hot mop under it and Redgard above it. So I’m guessing because we want to avoid sandwiches that I should not Redgard. Am I correct?
Thanks Roger!
Hi Robert,
Yes, you should resist that urge. Go have an adult beverage instead.
Should I drink a distilled beverage or would fermented be alright?
I don’t want to botch this project.
LMAO! Dealer’s choice. If you’re watching someone else work there are no rules!
Hi Roger,
I had previous posts before but it seems they’ve been deleted. Anyway, converted fiberglass tub/shower to shower only. Just installed my last piece of Durock and need to seal all joints,corners and bottom where board meets pan. Some corners are about 1/4 inch short and don’t butt together. Advise? Also, at the top where my last piece of Durock meets the existing wallboard is not flush. The wallboard is a little thicker than the Durock. Can I fix that when I tile by add more thin set? Lastly, should I tile my bathroom floor first before I tile my curb? I plan on tring to get seamless pieces of marble cut for the inside, outside and top of curb. I guess I’d need to do the shower floor at the same time as bathroom floor so the marble pieces will sit on top. A lot of questions huh? Help me fining.
I meant finish. Fat fingers!
Hi Rick,
I don’t delete anything, they may have been buried (I have over 20,000 comments here). Just tape and mud those corners. You can make up for the thickness difference with thinset as you set the tile. Yes, do the bathroom floor before the curb.
Thanks Roger,
What is the correct type of thin set to use to mud and tape seems? Should I run a bead of silicone along the bottom of the wallboard where it meets the pan since there is a slight gap? Then regard everything?
Hellooooo out there. Busy elf you are!
Sorry Rick, yes, I am. Just got back from Schluter training in Reno – all this knowledge doesn’t just appear.
You can use any type of thinset to tape and mud your boards – I missed that part of the question a little while ago.
Hi Rick,
Yes.
Mucho mucho thanks. Almost ready for tile!
Hi Roger,
Would it makes selse at all to have my pan liner on my pre-slope and then redguard the top of the final mud bed? Or is that just overdoing it.
Hi Myles,
No, it doesn’t make sense.
It may actually create problems for you by trapping water between two impervious surfaces, that will make stuff grow.
You don’t want stuff to grow.
Can I use green board behind my shower. Coat with Red Guard and then install my tile.
Hi Glenn,
Nope, you need to use cement backerboard. You can use kerdi over greenboard if you want, but that’s the only product specified for use with greenboard.
Hi there, thanks for your brilliant site.
I have a 2×2 metre ensuite which is on a level concrete slab. Rather than use a jack hammer to recess the concrete, could I build up the floor instead to create the fall? I have a rear drain and would like to have a channel grate for the waste. Ive been to lots of hardware stores and everybody has different advice. I really want to give it a shot myself
Cheers!
Hi Hazel,
You can create your entire bathroom floor with deck mud. It is still one of the best flooring substrates. So yes, you can build it up.
Thanks for spending so much time on your great site! I have a couple questions for you:
Existing gutted Basement shower on concrete with 3 cinder block walls, 1 of which is an exterior wall that’s been waterproofed and has floor to ceiling “bright wall” moisture barrier that I don’t want to remove. Waterproofing company said ok to penetrate moisture barrier with screws. Clamping drain installed, preslope complete, ready for vinyl pan liner, then final deck mud, then tile. I plan on hardibacking all 3 walls, tape&thinset the seams, then redgard on walls, then tile.
1. Can I use 1/4″ hardi instead of 1/2″ since the walls are already solid?
2. How do I make the hardi panels plumb with the folds of the liner in the corners? Build up the space above liner with…?
3. Silicone at final deck mud/hardi transition or can I paint redgard down onto floor a few inches?
Thanks in advance for your input!
Hi Troy,
You need to fur out those walls with 3/4″ ‘studs’ so you can screw the hardi onto them. If you are using a traditional pan liner you need space between the cinder blocks and the hardi. You need to create framing in front of the cinder blocks to do that.
1. It needs to be 1/2″ – you can’t go directly to the cinder blocks
2. With the framing you need to build.
3. You can paint the redgard onto the floor a few inches.
Roger,
I have a couple questions.
First, I purchased the Sand/Topping mix from Home Depot so I could mix in half of one bag of sand (25lbs.) to one 60lb. bag of Sand/ Topping mix. After it dried, it was more like concrete then a hard sand. I am not sure if there was any sand in the Sand/Topping mix at all. Please see the two pictures of when I was applying it and the other after it was dry. So my first question is:
1. Should I mix in more sand when I get ready to apply the final deck mud on the top of the liner?
2. The other picture shows the pan liner laid into place. What do I do with the exposed 2×4 frame that runs vertically up from the dam? Do I need to scab in a piece of liner on that face side of the 2×4 or do I just cover it with the plastic membrane when I run it around the entire wall of the shower area? When I install the PVC dam corner on that part of the wall/curb, do I glue it to the wood or should there be some water proof material on the vertical piece?
P.S. I sent you an email with this same set of questions. That way I was able to attach the pictures to show you what I am talking about. Let me know if you need anything else to help understand my question.
Thanks,
Rick
Hey Rick,
1. That is the correct ratio. You got a little too much water in there which leads to a more solid finished surface since excess water rises to the top. It may cause it to shrink too much, though, so you want a bit less water. Other than that you’re just fine.
2. The dam corner will cover the bottom three inches of that when you install it. It only gets glued to the liner. Bring the barrier down over that.
Thanks Roger!!!
I have another question; When I went to place my dam corners which are PVC (Home Depot) to the PVC OATEY liner, I used some PVC primer and PVC cement to glue the dam corners on the liner. However, even after pressing them together for about five minutes, the dam corners still did not completely adhere to the liner. I tried re-gluing the areas that were coming unstuck but that still did not work. So I used 100% silicone just under the lip around the entire edge of the dam corners and that seemed to positively hold the dam corner to the liner. Should I have done that? Or should I have used a different method to glue them in place?
Your help is great and I appreciate every bit of it!
Rick
Roger,
Another question to go with my previous question; Would putting a couple coats of Red Guard around the entire area of the dam curb help seal it to positively prevent any leaks?
Rick
Yes.
Hi Rick,
You used regular pvc pipe cement, that’s not the right stuff. The right stuff is called x-10 and is sold next to the membranes. What you have should be removed and replaced with the correct stuff. I honestly don’t think the silicone will hold up over time in that application.
Roger,
Thanks once again for the information. I went to Home Depot and they had Oatey “X-15 Shower Pan Liner Adhesive” so I am going to remove the dam corners and glue them to the liner with that. They did not have X-10. Is that the adhesive that I should use?
Rick
I have been working on removing the bleeping silicone for hours now. I tried denatured alcohol, “Goo-off” and also some silicone remover that is almost like a gel but that silicone is stubborn! Is there a perfect product that will make removing it easier than hours of elbow grease and the silicone remover? What if I cut that small portion out of my liner that still has silicone and glue in a piece of liner 2″ or so larger than the area that I cut out and glue it with the X-15 liner adhesive?
Frustrated………
Rick
I would just cut it out and use a larger patch. Not worth the headache. The x15 will seal everything up tight so you can make any size patch you need and add strips where needed as well.
My bad, x15. I get my product numbers confused sometimes, I only deal with about a thousand of them.
That’s the right stuff.
I am paranoid about the liner leaking after time so I am wondering if it is ok to put 2 layers of waterproofing as long as there is nothing inbetween them to trap the moisture? Can I install the pre-slope, put redgard ontop of the preslope, then the pan liner on top of the redgard and then the final slope, then the tile?
Thank you!
Yes, you can do that.
I purchased your book which has been awesome, but I have a question I’m hoping you can answer. I put the preslope down and was starting to put the Oatey liner down. I had to buy a liner online because I needed a 6’x8′ and could not find one in my local store that big. It came folded up. When I placed it over my preslope there are humps where the folds are. I put a marble down on the liner to see if it would run to the drain and it doesn’t. However, the marble did run on the preslope. The Oatey website said to glue it down using an approved adhesive to help get any folds out. Do I have my husband remove the nails out of the liner to take it back up and use the adhesive? Don’t worry he nailed it only at the top. We don’t want our dog to burst into flames! I’m also wondering if it is normal for the water to bead on the liner. I just poured a little to see if it would run to the drain and it just beaded up.
Hi Diane,
No, it is not normal. However, once you pack deck mud onto the liner it will flatten out and water will run to the drain just fine. Pounding deck mud like a dmv employee will flatten it out.
Hey Roger! Thank you for all of your help! I installed the hardibacker and final mud floor last night. My pre slope was extreamly sandy so I put a little more water in my final bed mixture. It has dried more like a concrete than a sandy finish, still very hollow sounding. Is that going to be ok? It wasnt sopping by any means but it doesnt have that sandy finish. I used the 5:1 ratio with sand and the toping mix like you said. I am now going to redguard the walls (I didnt use any waterproofing behind the hardibacker). Will it be ok to red guard a little bit onto the shower floor final mud bed so I can get it in the bottom corner? A question I have is for the shower wall tile install. Most people put a 2×4 on the wall to tile from a tile up from the floor. How do I do this without punturing the red guard and is it necessary to do? Also at the bottom where the wall tile meets the floor tile in the shower do I apply silicone. I am confused about when to do this and not to do it. And do I hang the vanity before I tile the wall or after? and for the FINAL (hopefully) question…I am tiling 2 walls in my shower. It is a neo angle so I am tiling the 2 walls at a 90 degree angle all the way over to where it meets the greenboard wall outside of the shower at the inside corner. I didn’t fill the joint with anything where the hardi meets the green board at the inside corner becuase I didnt want to deal with the thin set on the greenboard where I am just going to be putting paint. Will this be ok to leave as a small gap since it will be covered with tile?
THANK YOU!
-Bridget
Hi Bridget,
It always sounds hollow, it’s fine. Yes, you can paint your redgard about two inches out onto the floor if you want to. Ledger boards are not necessary (and most pros don’t do it, some do, some don’t), just fill the holes with silicone or more redgard when you remove them. Silicone at all changes of plane, that includes where the wall meets the floor. Hang your vanity after you tile. Yes, the gap is fine.
Dear Roger
I have a chipped but solid concrete slab after my demo of builder hackery. Please tell me how the layer of thinset over this should look before I either slope in deck mud OR level out deck mud for an expensive preformed tileable pan. Thinset over slab to make mud pan stick, right? Then nice square, plumb ‘shower box’ of cement board with 1/8″ gaps? And 1/4″ gap siliconed in under board meeting well cured pan? Tape and thinset seems? Then HYDROBAN or RedGard primer mix followed by three or so coats back and forth over a period of days of drying? Also have built out … If you saw walls and pan you would understand why ) metal wall studs with 1/2″ thick wood strips and have rethought that to the point I will take them down and build out with two thicknesses of Durock over metal studs.
Any potential glitches or total screws ups you can caution me on? I am giving myself three months to do this and refuse to do it any faster from studs to tile.
Still no email and I refuse to do facebook unless I make up a fake account. Glad you are on it though.
The gap at the cured pan can be 1/8″ as well, it doesn’t need to be larger. Other than that it sounds just fine. The layer of thinset can look however you want it to, it doesn’t matter, it’s just there to bond the deck mud to the slab.
Here is a question that may stump you…although I hope not. I got the pan liner in yesterday on my neo angled shower. It wasn’t easy but I folded and only cut what I had to. Put in the dams,siliconed around the drain. I did everything you say to do. I waited about 5 hours for everything to dry and then filled her up with water just under the curb. I marked a bunch of lines so I would be able to see if the water had gone down. I had already put the lathe on too to make sure nothing had been punctured. Now this morning when I went in to check on it the water hadn’t moved…great….except I saw a little darkness around the lowest part of the outside of the curb. I drained all the water and pulled up the liner to find the pre slope comlpletely saturated with water as well as the lower level of bricks are completly drenched….where is this water coming from and now what in the world do I do?!? Do I need to dig up the pre slope? I can’t figure this one out. Thanks for any help you can give!!
Hi Bridget,
It is absolutely impossible for me to be able to tell you where your leak is originating. The only way to do that is to examine it and figure out where you have something that isn’t sealed up correctly.
Hi Roger. I was talking with you on a different thread about creating a cinder block bench for my shower. Now, I’ve run into an unforeseen issue with waterproofing my shower floor. I created the preslope, using a clamping drain, with the intention of putting a shower pan liner on top of preslope, then the second mud deck for tile. Problem is that there is a vertical bulkhead surrounding a pipe on the back wall of the shower. The shower pan liner won’t fold around this nicely and I don’t want to cut it. So with the preslope and clamping/flanged drain in place, I’m afraid it’s too late to use redguard? I’m lost on what the best thing to do at this point would be, considering my situation. Can I still use redguard and mud on top of that to make of for the space between the top part of the drain and the flange (about 1 inch)? Or do I have to fold the pvc liner the best I can and throw another mud deck on top of that? Or is there a way to stick another drain top in there and make it work with redguard or another liquid waterproofing system?
Thank you sir.
Hi Dave,
You can use redgard in place of the liner. Paint the appropriate number of layers to get the thickness, go up the walls the same height then install your top mud deck on top of it. Works the same way.
You just made my day! Thank you!!!
Oh… concrete board on first or after redguard in this situation?
I would do it first, it’ll give you a seamless transition.
One more question….there is about a foot and a half hole where the p trap is in my concrete slab. How should I fill this in. The p trap is ABS pipe. Do I cement the entire hole or can I just use the deck mud and continue with pre slope?
Thank you for all your help!
Hi Bridget,
You can use either, I would use deck mud.
Hey Roger,
If I am going to Red guard over the hardibaker board do I need to use a vapor barrier behind the hardibacker? I don’t want to trap in any moisture…Also do you need to glue down the pvc liner other than the silicone bead? Would it hurt to red guard the top mud bed before tile? And would it hurt to red gaurd the concrete slab before the pre slope? If I have red guard on my slab could I use wood for the curb?
Thankyou!
Hi Bridget,
No, no barrier behind a redgarded substrate unlesss it’s a steam shower. No, you do not glue down the liner, the top mud deck holds it down. Yes, it may create a moisture sandwich and lead to mold. Redgarding the slab first is purposeless and a waste of good redgard.
No, you always need bricks on concrete IMO. Technically you may be able to use a wooden curb over concrete, but why would you?