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.
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Great Site!
I’ve placed My sloped floor in my shower and want to put Kerdi on it. My deck mud has popped in a few spots like it was to dry. I tried to sweep it up but it takes the top layer of the floor with it!
Can I just use thinset to fill in these areas, let it set then apply my Kerdi?
Man, you can’t be runnin’ around with a name like ‘Jim Savage’ being complimentary to people. Thanks for the compliment anyway.
As long as the area you are replacing is less than about 1/4″ deep then yes, you can use thinset. In fact you can skim the top of the entire deck to ‘lock’ all the loose particles in place and keep it nice and solid. Once it sets you can do whatever you need to on top of it.
If you have large chunks out of it you should replace it with more deck mud. You also need to ‘lock’ it into the void with thinset. If you don’t use thinset when filling the void it will be like having two separate mud beds which, in turn, may move separately.
If you install the kerdi on the deck you want to tile it first, let that set, then do your walls. I say that because you don’t want to be walking all over that kerdi once it’s down. You probably know that but I haven’t put up a lot of stuff about kerdi yet and don’t want you having a tiny hole in the floor of your shower where a piece of gravel was pushed through from walking on it repeatedly. If you want to do your walls first just skim coat the deck with thinset and let it cure then you can walk all over it without any problems.
Roger,
Great Site. Question the plumber replaced my drain for my shower, but put the bottom flange flush with the concrete floor. Now I don’t have a 3/4″ lip to start my pre-slope at.
Help Please
Hey Christopher,
What kinda plumber you got there?
Actually, it isn’t that uncommon for a plumber to do that, especially one that knows nothing about shower floors, eh?
About the only option you have is to start at nothing. You can actually do this although it is absolutely not recommended by the powers that be. Fortunately I am not part of the ‘powers that be’. Make sure you have thinset on every part of your concrete around your drain to get a firm grip on the thin layer of deck mud which will be in that spot. Start as high as you can around the outside of your drain and go up the normal 1/4″ per foot to the perimeter. You want to make sure the thinset is in place to help beef up that thin area.
Now, the deck mud may crack in that area being so thin so you need to make absolutely certain that you have it packed in there as tightly as humanly possible. Since it is only your pre-slope it is not imperative that it won’t crack. What you do want to do is make sure that if it does crack it won’t shift or move and create a void. So pack as much as you can there. With your top slope you want to do the same with the regular thickness above the liner. As long as you get as much in there as you can and pack it extremely tightly you should be just fine.
And give your plumber my website address.
Thanks Roger,
I think I fixed the problem. I took a 1/4″ piece of 4″ PVC pipe and cut it 3/4″ thick, Silliconed to the lower flange. Now I can level my pre-slope to the top of the pvc. Then put my liner down and attach on upper flange. Just had to get longer bolts to attached upper flange.
Should work OK.
i was also wondering if I could make my curb out of thinset instead of bricks. I have it formed so as to do it same time as pre-slope.
And you are the greatest. I had a locale shower builder come by and give me a price to put back my shower and I told him the old pan (33 years ago) was just layed on the concrete slab, that’s why it leaked after awhile, and he told me that is the way you do it. I told him I would be looking for someone else.
Thanks Again
Hey Christopher,
Can’t really envision what you did with the drain (well, kinda) but it sounds as if you’ve worked it out.
You can make your curb out of deck mud if you want – not thinset. (I think that’s what you meant but I wanna make sure) Thinset won’t work – deck mud, the stuff you’re making your pre-slope out of, will. Just make sure you get it packed in there really well up against your form so you don’t have any voids on the side of it.
THANK YOU! Contrary to what you’ve said – YOU are the greatest. If people would take the information available to them and make sure to ask potential ‘contractors’ the correct questions everyone could get rid of most of the problems in the tile industry. Most (99% – seriously) of the problems people have with tile installations are due to installer error! I’m convinced it’s one of two things – people that don’t know better and people that don’t give a crap. They both give my industry a bad name and they need to quit being given work! So thank you for doing your part. A contractor that knows the proper methods is worth his or her weight in gold. (That’s what I tell my wife, anyway)
If done correctly a shower will last well beyond the 33 years you’ve stated. Take your time and you will not be disappointed.
You rock!
I am getting ready to do my deck mud for my shower. I was wondering if you can use backer board for the curb. I have a hot mop over my floor now. It is also over the curb. If i can use backer board for the curb what is the best way to secure it to the curb ?
Hey Rick,
I don’t know if you can secure backer board to the curb with thinset or not. We rarely have hot mop around these parts. You can try, I guess, I just wouldn’t recommend it without first confirming that it would work with someone that would know. Unfortunately – I’m not him.
Since you’re doing deck mud anyway why not just add a bit of powdered lime to your leftover deck mud and form the curb out of that? (The lime makes it sticky so it will hang on vertical surfaces) Wet mud would make a better, more solid substrate for your curb anyway.
Sorry I couldn’t be of more help with the hot mop question. Sometimes I’m just an incompetent loser.
Roger,
THANK YOU for giving such great advice to all us “know-nothings”… for free, too!
Being the ‘know-nothing’ I am, I have a question. I have put my liner in and I’m having trouble with 2 things: I can’t seem to get it flat/tight on the bottom perimeter (where the floor meets walls) and I can’t get rid of those pesky creases in the liner. I know, I know.. I probably should’ve taken it out of the packaging and let it sit flat somewhere for a couple days. But I didn’t. Any quick ways to get rid of the creases so they don’t dam the drainage?
Thanks again!
- Jon (the over-confident, learn by failure, DIY’er)
Hey Jon,
Yup, should have laid it out and let the creases relax – but you already knew that.
The easiest way to get it to lie flat is simple – dump the top layer of mud on it. Deck mud is heavy and will hold it down, just make sure you don’t have any folds in it. Pounding down the top layer will flatten the liner. It won’t dam up the water. That will also make it lie flat in the corners as well.
Roger (The over-confident, learn by failure professional)
Thanks Roger! I thought dumping the mud might flatten it out, but certainly didnt want to try it and then have you tell me I’d screwed it up.
Its always the simplest answer, isnt it?
Learning …
Thanks again. I’ll email you again after I confuse myself again with the next step.
Hi I am considering a DIY job on my en-suite toilet/shower and have all the tiles and facilities removed, I am down now to pipes and concrete floor and sand/cement walls. We are considering a wet room shower area and are now considering our options.
Basically our floor is concrete and fully level at the minute and we have removed the old shower tray, would we need to create a slope to the drain and raise the floor with a sand and cement mixture and if so how much do we need to raise the floor ?? Our bedroom is only about 25mm above the current concrete floor so if we raise it and then have to add the membrane to the shower area what would be considering total height??
I have used your site for advice and seen mentioned shower tanking kits, would this be an option for us allowing a plastic type manufactured slope in our shower area only, what height would it be from our ground level ?
I appreciate all your assistance and perhaps my questions are senseless but we are considering this option and if it is beyond our means, Skillwise & financial we might just put a new shower tray in. Would we still need to coat with the Redgard membrane you advised in one post.
Thank you for time. Does your site take paypal donations.
Thanks
Hi Norris,
The height at your door would depend upon the distance to the furthest corner from your shower drain. Your floor, when finished, would need to be that distance in feet X .25 inches (or that distance in mm / 304.8 x 25.4) + 1.25 inches (127mm).
So, in American
that is
That distance in feet x .25 + 1.25 inches
Or, in metric
That distance in mm / 304.8 X 25.4 + 127mm
You can get the tanking kit which will give you a gradual slope up to the actual shower floor. The sizes vary from manufacturers but the average shower floor itself would actually be about 127mm high and the slope would go from the front of the shower to about 500mm out into the bathroom floor. I’m not real big on using them but they seem to work well enough.
This is all considering you using a topical waterproofing membrane atop your floor such as kerdi or redgard. If you use a traditional shower mud bed it would have to be a double layer which would make it thicker.
If you do end up putting just the shower tray in you will only need the redgard or waterproofing membrane on top of it if you make it from deck mud and plan on tiling it.
Your questions absolutely are not senseless! After some of the jobs I’ve torn out and redone I really wished the person that initially ‘installed’ them would have asked some of those ‘senseless’ questions.
My site does not take paypal donations, I may have to speak with my site about that! Just kidding, I’m happy to help, no charge. It’s what any self-respecting elf would do.
Hope that helps. If you have any more questions at all please do not hesitate to ask.
Okay, this is all coming together and making sense…sorry to be taking so much of your time…but another question (which I am sure will be answered in your Part 3 and/or your E-book): We have a concrete sub-floor — after we put the pre-slope in and the pan liner down, can we tile directly over the pan liner? Someone at Lowe’s (where I got the Oatey pan liner) told me we could do this since we have a concrete floor, but this seems contrary to everything else I have seen/read.
You are a great teacher and we appreciate your patience.
Hey Russ,
No apology needed at all. If I’d have gotten off my ass sooner and written part 3 already it wouldn’t be a problem.
You can not tile directly to the liner, regardless of what the “expert” at Lowes said. I think they should be flipping burgers rather than giving tile advice. On top of the liner you need to fabricate another mud base. This one will be 3/4″ and slope from the drain to the wall at 1/4″ per foot, same as your pre-slope. It should be a consistent 3/4″ thick since you already have your pre-slope sloped correctly – yes?
Your shower floor tile is then installed directly to that bed.
When tiling a shower, do you recommend tiling the floor or the walls first?
Sorry for the delayed response Russ, long day.
I will usually do the floor first on most of my showers. The advantage is time for me. Doing it that way I don’t have to use ledger boards and start from the second row, Then do the shower pan, tile, then go back and put in the first row. It just saves me a lot of time.
That said, you may want to do the walls first if you have the time. Start from the second row and finish the shower walls, then you can go in and make your shower floor, tile it, then put in your last row. This is sometimes better because you don’t have to worry about damaging the shower floor tile. If you already have your shower pan fabricated, however, tile it first. Easier to prevent damaged tiles than a damaged pan.
Did I confuse you yet?
Good advice…and it makes sense. One more question, though. Since we have not done the floor sloping or shower pan yet, we are thinking of doing as you suggest and put the wall tiles up first. Here’s the question: if we put up the backerboard on the walls and put up tiles from second row and up, won’t the pan liner have to then go up over the backerboard — rather than behind the backerboard? Would this be a problem?
Hey Russ,
Sorry I was tired last night.
Your liner absolutely needs to go behind your backerboard. I usually leave off a little over a foot of the bottom of the walls and actually start with the third row when I do walls first.
When you fabricate your pan you can then do your pre-slope and run your liner up into the wall then place your backerboard over it, then make your top mud bed and tile. See why it save me time to do the floor first?
Regardless of the time you have available you need to make absolutely certain that your shower pan is built properly. If a shower fails that’s where it will be 99.9% of the time. (Don’t you hate that term – 99.9%?) Okay, 100% of the time!
great advice – thank you….i just finished the first mud layer over the concrete shower floor. I have installed a pre-formed curb ( styrofoam ) over the 3 – 2 x 4′s for support. after i run the liner over the curb and tack it on the OUTSIDE – I need to install lathe, or something like that so the next layer sticks to the curb. do i use regular mortar mix, or ?? and how do you get the metal lathe to keep the sharp corners instead of rounded over the curb. thanks for all the help.
Hey David,
You can use regular deck mud for the sides of your curb as well. Just mix it a bit wetter or leave out some sand – go with about a 3 : 1 mix with portland cement or, if you’re using sand and topping mix, that’s what that ratio already is so just mix that straight.
You can take the lathe and fold it over on itself where you want the corners and use pliers – CAREFULLY so you don’t bust the wires, and squeeze the corner together. Then when you pull it back out into the shape of the curb it will hold it’s form and you can simply wrap it onto the curb.