The following five-part series gives a basic overview of building a shower floor for tile. If you would like a complete step-by-step of the entire process with all the little idiosyncrasies and details I now have manuals describing the complete process for you from bare wall studs all the way up to a completely waterproof shower substrate for your tile.
If you are tiling your walls and floor you can find that one here: Waterproof shower floor and wall manual.
If you have a tub or pre-formed shower base and are only tiling the walls you can find that one here: Waterproof shower walls manual.
Curb and Pre-slope
Properly built shower
There are a couple of options to create a shower floor for tile using deck mud. The first is a single-layer shower floor which can then be coated with RedGard or a similar product or covered with kerdi to waterproof it. The other is a normal shower floor with a liner which will have two layers – a preslope, the liner, then the top slope which is then tiled. This series of posts will describe the latter.
Before we start I should note that unless you are using the kerdi waterproofing method or utilizing a liquid membrane as your floor liner you should not have the backerboard installed in the bottom part of the shower. Your waterproof membrane for a shower floor will be installed behind your backerboard. The curb and pre-slope need to be completed before installing the lower wall substrate.
Creating the curb for a wooden floor
The first thing you must do is create the outside curb of your shower. You need to create the “box” which will become the inside of your shower floor. Depending upon whether your shower will be created on a wood or concrete floor will dictate what material you use for your curb.
If you have a wooden floor you want to use regular dimensional lumber. The 2 x 4’s they carry at Home Depot – those. That is the easiest and most readily available material. Ideally you want to use kiln-dried lumber. That is lumber that is, well, dried in a kiln. By removing moisture in this manner the moisture content of KD lumber is normally between six and eight percent compared to regular dimensional lumber at close to 15%. Why does that matter? Well moisture and wood don’t mix. As it dries wood has a tendency to warp and twist. The less moisture initially in the wood the better. KD lumber is best and regular air-dried dimensional lumber is also acceptable. NEVER use pressure treated lumber – ever.
I usually use three or more stacked 2 x 4’s to create my curb depending on the size of the shower. Simply screw the first one to the floor (with correct non-corrosive screws), stack the next one on top and screw it down, and so on until the desired height is reached. That easy.
Creating the curb for a concrete floor
Using Bricks for a shower cub
For a concrete floor you want to use bricks. Yeah, bricks. Just stack ’em. I use gray concrete bricks (no holes) and stack them two or three high for my curbs. You can use just regular thinset to adhere them to the floor and to each other. Just stack them in the shape you want.
You do not want to use wood for your curb on concrete. Wood will actually absorb moisture from your concrete and start to swell.
Creating the pre-slope
This is one of the steps most often skipped by a lot of people – amateurs as well as professionals. It is imperative! You need it – it’s that simple. Without a pre-slope your waterproof liner will lay flat on the floor. This does not give water anywhere to go. It will sit there, stagnate, mold, . . . you get the idea. With a proper pre-slope any water will drain to the weep holes in the drain and go where it needs to – away.
Lathe installation for wood floor
You need to first make sure your shower floor will stay where you put it. On wood you can use regular metal lathe.
You need to place what is called a ‘cleavage’ membrane beneath your lathe. This is just a sheet of plastic or tar paper stapled to your wood floor first with the lathe placed over it. The membrane does not make anything waterproof! If someone tells you that hit ’em in the head with a bat. It is necessary to prevent the wooden floor from sucking the moisture out of the pre-slope prematurely causing it to cure too fast (or not fully) and significantly weakening it.
When your membrane is down staple the lathe over the top of that. Just cut it to the shape of your shower floor and lay it flat on the floor and staple or nail it down. This gives your mud bed something to grab onto. In the above photo I have used plastic as my membrane and only have a partial piece of lathe in – make sure you cover the entire area below your pre-slope.
A properly prepared pre-slope
For a concrete floor you need to mix up some regular thinset except you need to mix it “loose”. That just means you need to add a bit more water than the instructions call for to make it thinner. Cover your shower floor area with this before you start installing your deck mud. The deck mud itself does not “stick” to anything, you need to supply something that will adhere it to your substrate.
Oh crap – Math???
To make the installation easier you’ll want to mark your height lines on your wall studs. To figure out how high it needs to be off the floor you need to figure out your slope. This involves a bit of math – don’t panic! It’s easy. Figure out which corner is farthest from the center of your drain. Your slope needs to go up in height 1/4″ for every foot. If your furthest corner is three feet from your drain center your slope needs to rise 3/4″. Easy enough so far, right?
Your finished floor (after your liner and top mud bed are installed) needs to be 1″ to 1 1/4″ thick at the drain. So, if we make the pre-slope 3/4″ thick at the drain it needs to be a total of 1 1/2 inch thick at all your walls. So mark a line 1 1/2″ from the floor all the way around the wall studs. This will be the height of your pre-slope at the walls. I try to make my pre-slope the correct thickness at the drain so it will be 1 1/2″ at the walls. This way you do not need to draw lines, just level your perimeter with the top of the 2 x 4 studs along the bottom of the wall. Depending on the size of the shower it doesn’t always work, but it saves time if you can work it out that way.
If your shower is not a square, and they rarely are, you still need to have the same thickness at the walls all the way around the perimeter. This means that you will have a steeper slope on the walls closer to the drain. This is normal. If you don’t do it this way you will have uneven tile cuts at the bottom of your wall. By doing it this way you will ensure a level line and, in turn, a level floor around your perimeter.
The height of your pre-slope at the drain can vary. It needs to be level with the top of the bottom flange of your drain. Regular drains have two flanges which bolt to each other. The pre-slope needs to be at least level or a touch higher than the bottom flange. Your liner then goes between the top and bottom flange to utilize the weep holes in the drain. This allows any water atop the liner to drain. The pre-slope supports the liner so it needs to be level or above every point of the lower flange. Does that make sense?
This is why planning is so important. Your drain needs to be high (or low) enough and your curb needs to be higher than your shower floor – naturally. So figure all this out before you build anything.
Playing with mud
Now we need to mix up a batch of deck mud. Check out that link, I’ll wait . . .
Okay, once your mud is mixed up you want to start packing it in there. If you are going over concrete and have your thinset slurry down, cover the entire bottom of the shower floor first to ensure the entire base will stick. If you have a large shower only spread as much thinset as you can reach over at a time. Start at the walls and pack your mud down really well – beat the hell out of it. Seriously, beat it like the last DMV employee you spoke with. You want to eliminate any voids and create as dense a bed as possible. Don’t worry, it won’t hit back.
Pack it down around the perimeter to just above your line. When you get that done get yourself a 2 x 4 about 18 – 24 inches long. Lay that on top of your mud bed against your wall and tap the 2 x 4 down with your hammer until it is even with your line. This ensures a level, even line all the way around your perimeter. Perfect! Now don’t touch the edges.
Properly prepared deck mud
Continue to pack mud into your shower base all the way from the perimeter down to the drain. You should have a straight line from the perimeter to the drain without any dips or humps. This will allow water to drain correctly without pooling anywhere. While this particular layer of your shower floor does not have to be exact, you do need to make certain it is fairly flat in regards to the line from the perimeter to the drain.
Ensure a consistent slope
That’s it. When you get it all packed in there it should have a shape similar to a very, very shallow bowl. Now leave it alone. Really, leave it alone. The next day it will be ready to install your liner and all that fun stuff. Don’t play with it until then.
In my next post I will show you how to install your waterproof liner. Until then leave your pre-slope alone. It’s fine. Quit trying to perfect it. We’ll do that tomorrow. Get away from it. Really. Stop staring at it . . .
Read this next if I haven’t already bored you to death: How to create a shower floor Part 2
We recently converted our garage to accomodate my 91 y/o aunt and put a handicapped shower in there, sloped a bit to drain. Shower is in the corner, shower curtain two curtains hung from ceiling and sides–water is still going everywhere when someone uses it. Need some type of rubber, something to go around the perimeter so that the entire bathroom floor does not get soaked or reach the main room which is no a mancave since my aunt’s passing. I have no desire to enclose the shower with glass, no need for more to clean! Any ideas besides gluing pool noodles to the floor?
Hey Joanne,
the best option would be to build a curb in front of that shower. It doesn’t have to be very high, but even a couple of inches would contain the water. Build a square curb and epoxy it over the tile, waterproof it with something like redgard, and tile it. Water will be contained and it won’t look like an afterthought – or pool noodles.
Hi Roger,
Regarding the bottom flange – If I’m understanding correctly, when the flange is pushed down over the drain pipe to the lip inside of the flange, the bottom edge of the flange should be 3/4″ above the floor.
If that is correct, I have problems. The plumber who did the work left the drain pipe too low and when I attached the flange prior to adding the sloped bed, it sits flat on the floor. Even if I were to slide the flange up, it wouldn’t be 3/4″ above the floor. Can I add an extention to the drain pipe to increase the height of the flange?
Thank you!
Hey Larry,
You can extend it if you want to or you can simply make the preslope about 1/8″ higher than the top of the bottom flange and leave it where it is. As long as the overall thickness, after both slopes, is minimum 1 1/4″ it’ll be fine.
PLease send reply to email
Roger,
I am so frustrated with these decisons of creating a shower floor. I will be starting from bare wood floor.
The problem lies where every time I do a search I find another method of doing this. Other ways state use just concrete with a layer of wire mesh? I am on a budget with this so this has to be done the best and least costly. Your method seems rather simple compared to others as well. Is it really as simple as your steps with the correct layers? I spoke to someone at HD to look at liners and he took me to a very simple very thin measure by yard material. I am now confused. The roll is only so big(will be going back within few days for exact meaurement of length of roll)at glance it could only be cut long enough to fit in one direction for some size showers. This cant be the right waterproof liner to go up the walls 6″ on all sides. It would most definatley have to be pieced together for big showers. Could this be a membrane like what you have as the layer of plastic? If so can I just simply go with roof paper on primer on the wood floor? And hope I can find someone in my town that knows what a waterproof liner cut to dimensions is! Also I will be doin a pebble stone floor so can they be put directly into the mud mix, let dry, then grout, then seal by the way what would you recommend for best sealer over grout for showerfloor?? I would much appreciate your feedback! Sincerely Waiting,
Crystal
Hi Crystal,
The liner comes in cut-to-size rolls as well in 5 and 6 foot widths. If your shower is larger than five feet in each direction the liner can be glued together. The liner is about 1/8″ thick. If that’s what they showed you then it is the correct stuff. The layers with the membrane between them is the proper way to build a traditionally waterproofed shower floor. It really is that simple. Straight concrete will not work, it needs to be deck mud.
The floor pebbles need to be installed onto the deck mud after it is cured, it cannot be simply placed into the deck mud before it cures. I prefer miracle sealant’s 511 impregnator pro.
Roger, Thank you so much for the reply! It helped me immensely! I will be starting this project soon and just want too feel comfortable! Thanks again for being here for us little guys trying to improve!
Roger
I like you method of using only cement bricks for the curb in the shower. My problem is, I have went to most of the local stores and no one offers the bricks without special ordering them. I have an abundance of concrete mix at the house. Would it be ok if i made some form boards and just poured a curb out of quickcrete concrete mix. Then remove boards once cured, and i would have a 100% concrete curb. If this is doable, should i use some sort of bonding agent in the mix, or thinset spread down before pouring the concrete. Should i add rebar or lathe in the mix.
Thanks
Hey Josh,
When making the curb out of all concrete it has a tendency to crack. So if you want to do that use lath inside of it. You really don’t need to do that, though, you can use just regular bricks with the holes and fill the holes with thinset. Works just as well.
Thanks Roger, I have found the solid red bricks and the red bricks with holes. I think tHey say their clay though, that still ok?
Yup, that’s what tile is made of.
They’ll be fine.
Roger,
Thanks for the quick reply on my other questions a few weeks ago! I have another one for you. I just got done piping in my new drain for the shower. The concrete slab where the old riser protrudes from the ground was cutout before and they seemed to have poured roofing tar to fill the void, iv heard this is normal on most installs for tubs and such. My question is, how should i go about filling this new void back in? Fill with sand then pour concrete to existing concrete level around it? I just don’t want any issues with my deckmud mixture or thinset adhering to what ever i decide to do. Thanks for your time, and look forward to your expert advise. I’m sure i will have plenty more to come for you also
Hey AJ,
Yup, sand and cement will be just fine, that’s how I do it.
Thanks again for yet another quick reply. I know i need to lay down some thin-set on my concrete before i start beating my pre-slope to death. I have a few questions about this:
1: Do i need to use a notched trowel for this or the flat edge of the trowel? If notched, what size notched trowel should be used.
2: Should this thin-set be given time to tack up? Once i spread my shower area with the thin set i can start laying my pre-slope down on top immediately?
3: To fasten my cement bricks to the existing cement do i need mortar mix or can thin-set be used? And do i need any type of bonding agent on the existing concrete.
Thanks for your time Floor Elf!
1. Any notched trowel will be fine, size doesn’t matter.
2. No, thinset does not tack up, it cures through hydration, it does not require air to cure. Just spread it and begin your floor right away.
3. You can use regular thinset, no bonding agent required.
Hi Roger,
I just happened to find your website, very helpful, thanks! I have a problem… Just completed a complete master bath redo – new shower, tile, vanity, etc. I have just discovered, after taking my first shower, that it does not drain properly. One half of the shower drains properly and dries out within 1 hr. while the other half puddles and doesn’t dry (9 + hrs before it finally dries out, but grout remains wet). Also, the corners don’t dry out until many hours later. Obviously this was not sloped properly. I don’t understand it, I measured it myself from the corner to the center drain and it looks like they used the right calculations of 1/4″ per foot. In any case the contractor is sending the tile setter back to fix it. Here’s my questions, can they fix this. They tell me it’s a simple fix, just chissel out the tiles and re-set them. REALLY? What about all the layers below, including the hot mop? They tell me they don’t have to go that far.
Is this a fixable problem or will I continue to have issues for years to come. HELP? What do I need to look for in fixing this?
Hi Michela,
Ask them if there is a preslope beneath the hot mop. If they tell you yes, make them prove it. If they tell you no then it is simply improperly built and must be completely rebuilt. My guess is there is about a 95% chance that no preslope exists which, again, means an improperly built shower which must be redone. They CAN NOT simply add more thinset under the tile and call it fixed.
Roger, below is the reply I received from my contractor to my question on the pre-slope…
“There is cement above the hot mop. The actual curve
of the cement is not that critical as is laying his thin set and tiles to
get the right drainage. He can add or deduct from the cement to re do it
correctly. Key is not to touch the hot mop. The Hot mop drain has weep holes
on the sides so if anything gets through the tiles it goes down the drain.
Even being off 1/16 can cause too much puddling so it is difficult. Eduardo
usually puts a level on it to check the slope. He then resets tiles if not
good.”
I don’t know about this answer, but at least I have something in writing – plus there’s a one year warranty on labor. Just my luck, ugh!
Hey Michela,
Not too sure what eduardo usually does, but it isn’t following standards for a proper hot mop installation.
You can show him this, it is the 2006 International Residential Code book section P2709.3 relating to Showers:
“Lining materials SHALL be pitched one-fourth unit vertical in 12 units horizontal (2-percent slope) to weep holes in the subdrain by means of a smooth, solidly formed subbase, shall be properly recessed and fastened to approved backing so as not to occupy the space required for the wall covering, and shall not be nailed or perforated at any point less than 1 inch above the finished threshold.”
The first sentence is describing the preslope. The biggest problem I have with that reply is the statement that “The Hot mop drain has weep holes on the sides so if anything gets through the tiles…” IF anything gets through the tiles??? Water ALWAYS gets through the tiles – always. That is the purpose of the weep holes, amount of sand in a proper mud deck (to allow water to flow through it), and a number of other specific items. He is treating it as if the slope of the tile itself determines whether or not your shower drains – that is incorrect.
When you first described it you stated that after the water drains half of the grout remains dark for hours – that is water beneath the tile which is not draining. If water is in a 1/8″ grout line, and has no moisture beneath it, it will dissipate in less than an hour. That obviously is not the case.
I would demand that the floor be removed and PROPERLY built, with a pre-slope, and preferably not by eduardo (who obviously has been doing it this way for 20 years…that’s sarcasm, by the way) You do, however, have codes and standards on your side. It was simply incorrectly built.
Mr. Elf,
Thanks for all the great advise. My question is my slab is not the most level so I was thinking that I might have to pre-level it prior to putting in the pre-slope. Is that necessary, or can i just make it up by marking a level line around the base of the walls? Also my drain is about 1/8 off level from front to back. If you suggest to level it out what product should I use?
Thanks,
Jon
Hi Jon,
No need to level it before the pre-slope. Just mark your level line and take the pre-slope up to that. There are no products to level your drain – it needs to be installed level to begin with. Unless you can physically move it and shim it to where it needs to be until your deck mud is cured you’ll need to remove it and re-install it level.
Roger, this is the most helpful site I’ve found, by far. My stall is built in a corner of an unfinished basement. The box is 2 X 8s on two sides, curb built with stacked 2 X 4s, but planned to use the existing 2ft. “pony wall” as the fourth side of the box. Will this work if I extend the liner under the cement board on that side, and what should I do to keep the board from damaging the liner? Thanks.
Hi Harold,
You need to remove the 2×4’s. The wood will actually absorb moisture from the concrete and begin to warp. Warping wood beneath tile is no good. You want to use bricks instead. I use the gray ones without holes and just use thinset to install them in the shape you need.
Now for your question.
Yes, you can use the pony wall. Run the liner up behind the backer and when you screw the backerboard back in stop the screws a minimum of three inches above the curb. Shim it out if you need to so it doesn’t curve out toward the bottom. It’ll stay wherever you put it. It takes A LOT to damage one of those liners, they’re stout. Just don’t put a screw through it.
Hey Roger,
I am confused. Not by you, you’re awesome and I appreciate your humor, help and patience with all us wannabe tilers.
Our plumber ‘helped’ us out by preparing the pan in our new construction, second floor, walk in shower when the tile guy told us “You don’t want to tile that, it’ll just leak.” (Same thing he said when I asked for niches.) Since I’m not a fan of cultured marble my husband thought it would be a good idea for me to tile it myself since I’m so handy – yeah, right. Thank goodness I found your site! So far I’ve finished 3 floors and a tub surround – with niche – thanks to your wonderful instruction.
Every time I think I’m ready to get started on that shower I hit a proverbial brick wall.
1st – the pvc liner was installed off kilter with 12″ up one wall and about 3″ on the opposite, and barely makes it over the top of the curb at the entrance. Not to mention the studs were not notched, and now the hole for the drain won’t be centered if I redo it. So, I figure I need to start with a fresh liner and take it out.
2nd – there is no mud underneath, only a styrofoam and cardboard sheet called a ‘Proslope’ laid on top of the subfloor. Ever heard of that? Is it any good or do I need to take it out and use mud?
3rd – under that they used Redgard on the osb subfloor and up the curb. I don’t know how many coats they used but it looks to be well covered. Do I have a mold sandwich? If so, what should I do about it? It would be a shame for my dog to go up in flames, I like him the way he is.
I would really appreciate any advice you have because it has taken me a ridiculous amount of time to get this far and I need to move on.
Thanks,
Linda
Hi Linda,
Yes, you need another liner. The liner needs to run up the wall a MINIMUM of three inches above the curb all the way around the perimeter.
The proslope works just fine. It does need to be adhered to the substrate with thinset. DO NOT use any PL glue or anything else as people are prone to do – it will dissolve the foam. Just regular thinset.
The redgard is not going to have the same effect on the floor as on the wall, so no mold sandwich. You’re fine there. No real reason to have it, but it won’t hurt anything.
Thanks so much! I should have asked a long time ago, it would have saved so much aggravation.
What do you mean the “redgard is not going to have the same effect on the floor as on the wall”. How is the floor different than the wall, is it a temperature difference so only for exterior walls would it be a problem?
I’m planning to do my entire shower, pan, walls & ceiling with redgard and want to make sure I have everything right in my head. My crawlspace can get down in the 50’s in the winter and I want to make sure the redgard won’t cause any problems waterproofing my shower floor.
Thanks, Dave
The floor does not have a wall cavity in which moisture cannot dissipate. There is a minimum of 3/4″ of deck mud between the barriers – in which cement crystals actually utilize and rid the deck mud of excess moisture. There are SEVERAL differences. Your crawlspace is not the same as a sealed wall cavity.
Hi! I’m about to rip out the fiberglass tub/shower combo in my master bath and replace it with a tiled shower, keeping the drain in the same location, but adding a couple of inches to the width of the existing tub’s footprint (thus drain will be offset and a little off-center). I’m trying to save money by doing part of the project by myself, namely Hydro Ban waterproofing and tiling. I have purchased a roll of six inch strips of Laticrete’s fabric for my corners (and drain???). I am having my contractor install the concrete backerboard for the walls and prepare the shower base for me. I am on a slab. I’d like the contractor’s part to be as fast as possible to save labor costs. Do you think I’d save money and/or prevent myself from messing things up with the waterproofing if I get a Kerdi drain, since it seems like it would simplify the base preparation (no divet needed, right?) and be pretty straightforward for me to use with the Hydro Ban?
I’m trying to understand the process here – would I need more visits from my contractor or otherwise increase labor costs to do a base that requires a divot?
Now here is some info that could be a game changer: the mosaic tile I plan to use for the shower floor is only 3/16″ thick. On the Kerdi website it seems like that is too thin for their drain. Is it too thin for all drains?
If that tile could be used with a non-Kerdi drain, how do I need to do the waterproofing around the drain?
Clearly I’ve done enough research to thoroughly confuse myself.
Hey Jenny,
Any drain can actually be used for any type of tile – you just need to know how to do it. With hydroban the kerdi drain would absolutely be the way to go – it will cut down on the amount of labor involved as well as fairly eliminate chances of improper installation. The amount for the labor – I dunno, I’m not building your bathroom. I will say when given the choice of kerdi drain or divot I’m buying the drain every time.
Hi Roger,
Sorry, I know this is my third post today, but I promise after this one, it will be strictly beer drinking for the rest of the day, so I won’t bother you. Do I need a divot if I am redgarding the base of the shower? The redgard site doesn’t mention anything about a divot, but having spotted the divot in several places over the last few days, when would you need a divot?
Thanks, Dave
Yes, you need either the divot method or a topical drain when using a topical waterproofing method on your shower floor. The redgard surface preparation pdf here: Redgard substrate specifies the divot method on the third page.
I just de-constructed my basement bathroom and found the shower had masonite walls and a concrete drain base with a drain centred at 17 1/4″ to the left and 18″ from the back. Both of those are fixed walls. I took out that concrete pad because it wouldn’t allow for the cap on the new fibreglass shower stall. Now I find the new base has a 2″ drain at 18″ x 18″.
Does this mean I have to chisel out the floor and replace the drainage pipe?
advance thanks!
Hey Norman,
If the walls are fixed and you don’t have any wiggle room in the drain then yes, you’ll need to move the stub-out of the floor drain to the center or use a different type, size or brand of base which is adjustable. I don’t even know if they make those, to be honest. Unless you can find one which will fit your specific measurements you’ll need to move the drain.
I have just finish framing my new shower and had a couple of questions:
1. My plumber installed the drain level left to right but not front to back ( probably an 1/8″ off ). My plan was to use the highest edge to get my slope. Is that the correct way to do that? I figured I could level the drain with a washer or two under the bolts.
2. You say never to use pressure treated lumber for the curb. I used PT around the base of the shower between the 2x4s and for the curb per my (apparently crappy) do it yourself book. Can I get away with just replacing the curb with KD 2x4s?
3. My local box store advisor suggested mapei ultraflex2 for the floor. Will that work or do I need to use your deck mud recipe?
Thanks in advance.
Hey Mike,
1. Yes, start at the highest edge, gauge your slope from there and shim up the drain if you can. Then smack your plumber.
2. Yes, the curb is the most essential place to NOT have PT wood. It is wrapped over all sides with tile. The base of the shower will only be pressing against the substrate and tile, HOWEVER, it also has other places to transfer that pressure – back into the wall cavity. It will take the path of least resistance. The curb only has one direction to aim that pressure – into the back of your tile.
3. The ultraflex II is great stuff and will work very well for installing the tile. If they suggested it be used to create the shower floor in lieu of deck mud – they’re idiots. The shower base substrate needs to be fabricated from deck mud. Ultraflex II is only a thinset intended to adhere tile to a proper substrate, not a material to create that substrate.
Mike,
I’ve got the same issue with my drain being level from front to back but not left to right. How did you end up handling this?
Thanks
Hi I think I’m going to put quartz on the floor of the shower. Do I still have to slope the floor to the drain because the quartz will be sloped from the factory already. How do I tie the drain from the quartz to the floor drain.
Hi Gino,
I don’t know. I would need a link to, or more information about, the particular quartz you are using for your shower floor. Quartz, to me, is simply another stone which can be fabricated to whatever you need, most often simply in the form of flat tiles or slabs. I need more information about the particular product you’ll be using.
I’m doing my first tile shower, and put my preslope mud right on the subfloor without any lath. It looks fine, but will I have problems down the road? It’s a 3’x5.5′ shower and the joists are spaced at 12″. I’d rather not tear it out, but of course it’s easier now than later. Thanks for the help.
Hi Clyde,
With a shower that small it won’t be a problem at all. You simply have what is known as an unbonded mud bed – completely fine.
Roger, you know how I keep joking that I might end up doing this myself. Well, it keeps getting more and more real over time that it might actually happen so this is why I am asking some real stupid questions. The plywood hole is cut for the drain already and am confused where the drain base(bottom portion of the drain assembly) should lay on the plywood floor. The Oatey drawing shows the bottom portion of the “lip” of the drain base laying on top of the plywood floor and the Lowes’ professional said to put it there too, but you know how I don’t really trust what they say. By doing it like that it would leave only 3/16 of an inch space for the mud and I thought the thickness of the preslope mud at the drain should be more than that. I followed your instructions how to figure out my thickness of the preslope at the drain by doing the following: The furtherest corner from my drain is 3.33 feet so that means the thickness of my peslope needs to be .83 at the drain and 1.66 at the walls. Is that correct? I think I did it correctly so how does one get that space? Does one get that space by having the knobbie things of the drain base(where the screws go in) lay on the top of the plywood floor? If that is how one gets that space, I think the guy cut the hole too big since the knobbie things are now only partly laying on top of the plywood floor, but there is a 1/4 inch gap between the cylinder portion of the drain base and the plywood so don’t understand how a good amount of mud won’t seep through that gap. Hope I explained things well enough for you to understand. I really did try to explain it so you could visualize what I am talking about and Sparky wouldn’t burst into flames.
Thanks,
Ceci
The bottom portion of your flange needs to be raised to the height your drain needs to be at the center of the shower. If it needs to be 7/8″ or so at the drain then it needs to be raised to that height. It can be placed on the plywood but it weakens the support in the center of the shower.
I’m sorry I am starting with a bunch of other questions, but assumed I wouldn’t have to know so much details, but now not so sure about the tile guy who is doing the bathroom. Seems like a very nice man, but I don’t need nice, I need it done correctly. So, should one put a bead of silicone(bought kitchen and bath Dupont) around the bottom of the flange(the bottom part of the drain)?
Thank you again and again,
Ceci
No – only between the liner and bottom flange.
Oh my gosh, one better reinforce one’s underlayment and subfloor supper strong since all that “cement” is super heavy. Know exactly how heavy, helped the helper bring it into the house since the tile guy hurt his back. No, not much done to the bathroom today. Yes, now hoping it will be done by Christmas. Not sure if that is a “joke” or not
Ceci
Roger,
I’m workin on my first bathroom gut and remodel. I’ve got it down to the studs and concrete slab. Looks like i’m going to have to take out the concrete around the drain and cut it out before the pee trap, throw on a boot and convert to PVC so the “new” three peice drain, will work. that sound right? not fun….my other question was that I’ve seen people mentioning that they put up a 2×10 blocking at the base of the shower, any con’s you see to doing this, is it that overkill? i know when i finsih with my final slope itll be above the base plate, so i could see having a higher wall being beneficial????
Thanks in advacne oh mighty elf,
Kreston
Hey Kreston,
Yup, you have the drain aspect correct. And yes, it also sucks.
Many people use the blocking and it does help a lot. I do it sometimes, in situations such as you’ve mentioned when the slope will be higher than the base plate – makes it easier. Make sure you keep it back about 1/8″ from flush so the membrane has room without forcing the bottom of the wall out.
Roger,
Thanks for getting back to me. I finished my above steps last night. I also put the curb in. Two layers of concrete brick set with thinset like you suggest. I’m wondering if i set the ends correctly? i applied thinset to both of the ends that touch the base plate. was it wise to connect the brick to the wood framing via the thinset? Youve said so many times that wood always moves throughout the year. If that wood is connected to the ends of the bricks, wont that cause movement and issues down the road? I’m probably overthinking it all, but thats just what us 1st timers do! I’ve really enjoyed your blog and definetly appreciate all the wonderful information.
Thanks,
Kreston
Hey Kreston,
That wasn’t really necessary but it likely won’t cause you any problems. The amount of brick connected to the wood is minimal and if anything gives way it will likely be the thinset before any tile. If the wood swells and compacts the curb (sideways) the weakest point is going to be the thinset against the wood. I think you’ll be fine.
For a concrete floor, you recommend applying a loose thinset before putting the deck mud down to create the preslope layer. Do you lay the deck mud down on the thinset while it’s still wet, or do you let the thinset cure first?
Place it on there while it’s wet. Once it cures it will permanently attach it to the concrete.
Roger,
If I rermove the wood dam (see prior post) and replace with brick how do I attach the liner to the brick? ( Nail to outside with a wood dam). Did I miss something? I would really like to leave the PT bottom plate. I will do whatever suggest.
Thanks for your patience and help.
Paul
The liner is folded over the brick and held in place with the wire lath only.
Rodger,
I just read that I should NEVER use pressure treated lumber for the dam. I have done that. I can remove the top two piece but the bottom one next to concrete floor will be a challenge, as I have other framing on top of it. What do you suggest? Also why is PT lumber not good to use on the dam?
Thanks Paul
Hey Paul,
You need to remove that bottom piece as well. Is there any way you can cut it in half and pull it out from each end? Once framing is completed over most curbs it is fairly independent of the curb itself. Pressure-treated wood is infused with moisture in order to prevent it from expanding when wet or exposed to moisture. A properly build shower allows no moisture to the wood or framing. The moisture in the PT wood will slowly dissipate. This causes both moisture and vapor behind your waterproofing layer and causes the PT wood to dry out and twist / warp.
Roger,
Thanks for the help on the mud mix. The water that rose to the top gravatated towards the center and then slowly went away. You were right, it looks fine and I’m good to go. I’ve got another question, I know what you’re thinking, “another damn question that he coulda
looked up!”. We don’t have internet out here in this north florida swamp. I’m doing this on my phone and it sucks. Hey but at least people respect you enough to ask you important questions. All anybody ever asks me is “Hey Yogi, are you OK?
Here is my question. I am using 8″X10″
ceramic tiles on the shower wall with either 3/16″ or 1/8” spacers. Should I use sanded or unsanded grout on the wall.
Billy Joe Bob down the creek at Cedar Stump Carpit & Tyle
says “Thet sanded stuff ain’t gonna stay put Yog. You is gonna have fits and ittle indup looken like a dog on fire. Fetch yerself a poke of our unsanded stuff. It’s eezzeer than skinnin a skunk on a flat rock.”
Thanks for your help. I’m paddling faster cause I hear banjos.
Yogi
Hey Yogi – are you OK?
The sanded stuff will stay put Yog, really. Use it. You’re dog will be fine. And tell Billy Joe Bob and his other brother Darrell they need to change the name of that there store to reflect the fact that they also sell motor oil.
By the way, your banjo comment made me laugh my ass off, I watched Deliverance again night before last.
Thanks again Roger,
I have one more dumb question. Oh, by the way, thanks for the info on Lacrete. I’m going to pick up some of their grout and matching silicone. My dumb question is at the change of plane from wall to wall and floor to wall do you grout the corners and caulk over them or omit the grout there and just caulk the gap?
Oh, by the way, it’s now Billy Joe Bob and his other brother Darrell’s “Cedar Stump Carpit & Tyle & Oil”. They liked your oil idea on the sign. They carry Slippin Gear Racin’ Oil. “If it ain’t Slippin, come see us!”. When I paddled down there this morning I smelled smoke. I knew it was not my dog Blue, cause he was next to me. It was Billy and Darrell’s toilet. It caught fire and was all burned up. Darrell was all excited and happy that they got it put out before it reached the house.
Yogi
Hey Yogi,
Just caulk or silicone in those gaps – no grout.
I understand fire to rid the toilet of smell but holy shit! That’s goin’ a bit far.
Yup, that trowel will be fine. Yes, modified it fine.
I was always told I could fuck up the moving parts of a pillow. Never saw those either.
Hey Roger, everything you said was right, right , right! And I learned a couple of things. Take it easy with a rubber mallet. You would have thought after the first two I would have rememnered I ain’t nailin up wanted posters. And if you are going to put your V notched trowell in a bucket of dirty sponge water, notches down. Ouch! I guess a little blood in the thinset makes it stronger. Oh yeah, and if you buy listellos from Cedar Stump Carpit Tyle & Oil that are in the bargan barrel, check em out like you are buying 2 X 4’s. Ever dang one of em is real purdy but bowed like old Blue’s hind legs. He didn’t burst into flames yet but there was smoke comin out his ass. Yogi
Mr. Elf,
I mixed my final slope with 90lbs sand topping mix and 45 lbs play sand. It had the sand castle feel to it, dry but cohesive. I pounded it hard with the float and I got it level around and pitched right but a lot of water has risen to top. Do I have to tear it out now or in your wiseness canI go get a brew and not worry. Thanks, Yogi
Hey Yogi,
You just mixed it with too much water. No big deal really. The problem with having too much water is that your mix will shrink as it cures. As long as you still have level and good slope it’ll be fine.
I have a shower floor with 6″x6″ porcelain tile and it isn’t sloped enough. I have extended the drain and now want to create a slope and re-tile. I plan to leave the existing tile in place. Should I slope it with thinset and then tile or are there other suggestions on how to accomplish this?
Thanks for your help!
David
Hi David,
It would be better (and will last) if you install a mud bed above the existing tile. Just like installing the top mud deck when building it from scratch. It’ll last that way. You do need to ensure that your waterproofing is working correctly.
Have a couple of questions regarding bricks for the curb.
– Do you lay the pan liner over the bricks? Seems like the bricks could tear the liner – should something be between the liner and bricks?
– How do you attach the liner to the outside of the bricks? Could use masonary nails, but concerned about cracking the bricks and/or dislodging the bricks. Plus they may not hold the liner very well w/o a washer of some sort?
– for both wood and cement floors, when you put the lath in for the curb, are there any handy tricks to help prevent puncturing the liner as you lay the lath over it?
Hey Mike,
Yes, the pan liner lies over the bricks. A 40 mil pan liner is much tougher than most people think – really. Nothing between the liner and bricks.
You do not attach the liner to the bricks, the lath holds it in place. You don’t even really need to attach it when wooden curbs are used, it just makes it easier to hold in place until the lath is in place.
Use a 2×4 and bend the lath around it giving it the shape of the curb before you place it over the liner. Overbend it in a ‘U’ shape so that when you pull the sides out to place it over the liner it ‘springs’ back and holds the liner in place snugly.