And the rest . . . 
Once you have your entire perimeter done you simply need to pack deck mud into the rest of the base from the perimeter to the drain. Once again – beat the hell out of it. Seriously, pack it in there really well. The more dense your floor is the better. You need to ensure that the line of the floor is straight from the wall to the drain all the way around without any major humps or dips. It takes time and patience – use both. This step is critical since this is the substrate your tile will be installed upon.
Once you get the remainder of the deck mud packed into the shower and have it correctly packed and leveled just let it set for at least 12 hours, 24 would be better. Really, leave it alone. There is something about a freshly packed mud bed that makes people want to pick at it – it’s alluring – and a bit disturbing. But you need to leave it alone. So quit poking at it.
After it sets for about 12 hours you can fine tune it, so to speak, if you need to. Any un-flat spots can be scraped, rubbed, or sanded down to flatten them out. You can use regular sandpaper for this – really. Just make sure you have a flat surface from the wall to the drain. FLAT – not level. You want this surface absolutely flat.
If you have not yet done so you can now install your moisture barrier and backerboards. Now that you have a large waterproof box you are ready to install your tile and make it look all pretty. The hard part is finished. As with any proper tile installation the underlying substrates are the most important. Take your time with the preparation, it is imperative. Without proper preparation any tile installation is doomed to fail.
And your dog may burst into flames.
For detailed information about how to create your curb and tile substrate for it read this: Creating a curb for your shower.
Need More Information?
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.
Can you do both Redguard and the PVC liner to the shower floor for the extra protection. I have Redguard left over after doing the walls and thought it wouldn’t hurt to put some on the final portion of deck mud before I tile instead of wasting the expensive Redguard.
Hi Markus,
No, never. If you install two barriers with mud between them you WILL have mold. And it will be a LOT of mold.
Thank you for the info regarding how to polishing marble. Yes it took some time but is now complete. However I now have a new challenge which brings up 3 new questions. Marble seems very brittle and is full of natural crack lines that are visible in most of the pieces. Some appear as though they actually have been glued together to make up the 12 x 12 individual tiles. One piece of my marble pieces has broken in one of these natural cracks. And of course it is one of the most intricate to duplicate, although not impossible as I did do it the first time. 1) Can it be glued back together and if so what type of glue do I use? The two broken pieces puzzle together and look as natural as they did before it cracked in half. 2) Also I remember seeing a post that led me to believe I adhere these to the deck with something other than thin set. I can’t seem to find that post, so I am requesting you to repeat yourself. 3) Because of these natural cracks I have concerns in regards to there installation. Firmly pressing them into the thin set seems like I am asking for more broken marble. The small area around my tub is small and many of these pieces are 2″ x 10″. Do you have any recommendations or tricks for me?
Hi JD,
All marble has striations, not all marble has weak striations (the natural crack lines). If weak striations are prominent in your particular marble then it is normally backed with an epoxy resin and mesh. If that is the case it NEEDS to be set with an epoxy setting material. Thinset will not bond long-term to the resin backing. Yes, they can be glued back together with epoxy. If you get a 1 foot square piece of plywood you can press them in firmly with that. It will even the pressure and won’t crack the marble. (or a 2×10 piece of plywood, whichever you’re working with)
Hi Roger,
I do not see any mesh. What I do see in some full pieces are what look to be apparent glue joints. The back of each piece is not polished and therefore the glue joint prominent. You mention I can glue it together with epoxy, is there a special epoxy I should look for. I am still unclear as to what to set them in. Is some type of thin set or epoxy and what kind of thin set or epoxy. The natural crack you call striations look pretty cool. You have added a new word to my vocabulary. Bet you did not realize the amount of English being learned from your efforts on this site. You are greatly appreciated by myself and many others here that look for your guidance. Thank you
Hey JD,
If you don’t have webbing and resin on the back (it would be shiny) then you can set it with a modified thinset. Nearly any epoxy will work with stone.
I plan on using kerdi waterproofing and drain system over my mud bed. Will u please comment on this method?
Plumber installed the drain flush with the floor (like isoften the case with concrete floors. I floated my preslope but left about two inches around the drain. Lathe runs within 1″ of the drain. The drain is flush and you can get the mud bed less than 1/4″ thick I plan to feather this area out with a rapid setting skim coat?
Do you think this will work?
Hey Ron,
Yes, it will work fine.
Do you use standard deck mud to go over the curb?
I could not find it in any of your posts. Doesn’t mean it’s not
there, I have been known for missing things right in front of me.
Cary
Hi Cary,
I use wet mud. It’s regular deck mud with 1 part powdered masonry lime in it (to make it sticky). If you want you can also use stucco base coat straight out of the bag – nearly the same mixture.
Roger,
Do you wait after you do the deck mud to do the curb, or do you do it at the same time. If you are suppose to wait, do you do anything to make the curb bond to the deck mud like you do for the deck mud to the concrete floor ?
Thanks
Hi Cary,
I do both. You don’t need to do anything to make it bond. It will bond to the deck mud to some extent due to the lime in the fat mud, but it’s a completely different portion of the shower with a change of plane, so not really necessary. If you put the wire lath over the curb before you do the deck mud the shower floor will lock into it and it will all be tied together anyway.
Rodger,
Question regarding marble 12×12 tiles. I have a corner sunken tub and a spate corner shower. I would like to buy 12×12 marble tiles to frame the small top deck area around the tub and cap the stub walls of the corner shower. I have a wet saw to cut the marble however this will not leave a nice finish on the edge. Is there an economical way for me to create a round over / radius profile on the edge of the marble very similar to a piece of bull nose tile. The marble tiles are 5/16″ thick.
Hi JD,
It’ll take some time but you can do it with an orbital sander and diamond sandpaper. You can google the sandpaper, it’s fairly readily available. It’ll also save some time to bevel most of the corner off with the wet saw rather than starting with a 90 degree angle.
Thank you for your wonderful site. I kept reading hoping someone else would have had to ask you this question. Some years ago (before we knew of your site) my husband installed a curb-less shower on a plywood base and luckily he did all the steps you mentioned – all except 1/4″ slope/foot. (Used 1/4″per 2 feet). Regardless, this curb-less shower allows water to run out further than it should. The bathroom is all tiled etc but I am willing to add a curb to fix this problem and am asking what you would suggest? My husband and I are in our 80’s and the shower is only used 3 times a year so I prefer to add the curb right over the tiles. Should I use brick (recessed carriage bolts into floor) and deck mud instead of 2×4 (sealed in membrane etc.) since I want to install the curb over the tile or would it be better to build it straight out of thin set and deck mud over roughed up tiles?
Hi Donna,
Going over the curb it would be easier to simply rough up the tile, thinset some bricks there directly to the tile, waterproof them and tile right to them. It will be the minimum amount of work and the smallest possible curb you can have there. As long as you rough up the tile the thinset will bond the bricks to it very well.
Hi Roger,
First of all great site and lots of great information. I too like one of the previous posters ( mary I think ) was about to make a rookie mistake. After setting the final deck and am about to put up my backerboard. My question is how to I secure in the bottom part of this wall as the screws will obviously go through the rubber membrane which runs up 6 inches alone the studs.
Sorry if I missed the information on your site I looked but could not seem to find it.
Thanks
Stephen.
Hey Stephen,
You can install fasteners down to three inches above the height of the curb without problems. (Realistically right to the top of the curb, but standards and all…) That will secure it just fine.
Thanks Roger much appreciated.
Stephen
You website and your willingness to help all of us is just Fantastic. Thank you. I am at a point where it is time to leave the shower and prepare the remainder of the room to a point where it is cabinet and tile ready. I have not selected any tile type, tile size or tile combinations at this point for anything. I want to prepare the floors now and my qestion is in regards to thin set. I obviously will need thin set for my shower and for the overall bathroom floor and bathroom walls. On the bathroom walls (outside of the shower), I was going to use AcrylPro tile adhesive and regualar thin set everywhere else. I need to lay my 1/2″ hardibacker over the 3/4″ OSB subfloor setting on 2×12 double floor joists. Need to by thin set and want to know if what type of thin set to buy for the following areas. I hope I can buy one type for all areas. Thin set for under hardiboard over OSB floor substrate, Thin set on top of hardi and under tile for overall bathroom floor and thin set for on top of redgaurd and under tile in shower and around tub and tub deck
Hey JD,
You can use the same thinset for all of them. Any good modified thinset will work, versabond is normally readily available and will work well, as would mapei ultraflex.
Just varifying you noticed this part of my post?
On the bathroom walls (outside of the shower), I was going to use AcrylPro tile adhesive.
This is the white cream/paste type thin set. Less messy and easier for me to control applying to walls
Yeah, but I spaced it as I was answering questions.
(that normally only takes about seven seconds – the ‘spacing it’ part…)
As long as it isn’t inside the shower or any wet area (and it isn’t natural stone) the acrylpro will be fine.
Hey Rog, My shower project is coming along nicely thanks to you, Thank ya very much! I have a question though, I started tiling the walls of the shower from the second course of tile, placing a ledger board underneath to hold them in place, I just installed the floor tile and am now wondering if it is preferred to place the first course of tile so that it is sitting on the floor tile then caulk or have it raised an 8th of an inch above the floor tile and caulk it, leaving weep holes every so often? (something I would have not done if not for you) As well I have heard discussion of others stating that they have caulked the joint with silicone where the backer board meets the mud shower pan, I did not do this however and think it is no big deal but just wondering if the all knowing Floor Elf caulks this seam or not? thanks again Rog!
Hey Jake,
If you have a tiled floor it usually looks better with the wall tile 1/16″ or so above the floor tile then siliconed. If you have a traditionally waterproofed shower floor you don’t need weep holes (everything runs to the drain behind all the tile – including the floor tile). In certain applications, namely using a topical liquid waterproofing, that gap between the backer and floor is caulked, but not in yours. I’m assuming here, of course, that you have a traditionally waterproofed floor?
Thanks again Roger, Ya sure do floor is waterproofed following your instructions, tested as well does not leak YayyyY! As well during the grouting phase (I am going to caulk all corners and changes of plane) would you advise caulking these corners and areas first then grout or grouting first?
Thanks again, reallly appreciate your time and insight
It’s normally easier to caulk (silicone) first, let it cure, then grout. I simply don’t have the time to do that on my projects so I do it the other way. Either works fine.
Roger,
This was a very helpful tutorial as I am getting ready to do my dry mud bed. I believe I am in good shape on the pre-slope and the liner so the pictures and explanation were hugely helpful. I do have a question though… I am going to use Hardiebacker 500 for the walls. I’ve ready conflicting into on whether it’s acceptable to embed this into the dry mud bed. I’ve heard that you should leave an 1/8″ gap at the bottom of the Hardie but I’d prefer to have it in the mud.
What is your professional opinion?
Hey Mike,
You can do it either way. I prefer to have it in the mud bed as well – it holds it in place.
Excellent, Roger… it’s what I needed to hear.
Hi,
I’m a little confused as to how the backerboard gets attached on the bottom. The rubber mat goes up the wall 6-12 inches so I can’t put a screw through that when installing the backerboard. So how do you attach it so that the bottom foot of the board doesn’t flex?
Hey Steve,
The bottom of the backer is embedded into the top deck of the deck mud. The deck mud holds it in place. Alternatively you can either chisel out notches in your studs so the liner will fit in them flush, then the backer will stay in place and flat, or you can shim out the studs above the liner so the board sits flush. Failing to attach the bottom 9-12 inches of the backer is NOT going to cause it to flex, nor will it flex. Provided it’s attached properly above the liner it isn’t going anywhere.
Hi Roger –
Our membrane for the shower pan goes up 12 inches from the floor….When we installed our hardibacker, (after the final deck was done) we made a rookie mistake (not having read your site yet….) and thought that like drywall, you should screw in the bottom of the hardibacker…obviously that was not a good plan…What can we do now to fix this??? We are going to redgard the hardibacker and the curb. Can we alleviate the issue by painting the redgard all the way to the bottom of the wall?
Hi Mary,
You need to remove the bottom pieces of backerboard and patch those holes in the liner. This can be done with the extra pieces of membrane you have or cut a 2 inch strip off the TOP of one of the walls, then cut it into 2 inch squares to patch. Then reinstall your backerboard – without the bottom screws.
You’ll need the same glue you (should have) used for the ends of the curb.
Alternatively (and NOT recommended) you can fill those penetrations with silicone or redgard – you’ll still need to remove the backer and do this directly on the liner though.
Hey Roger,
Quick question on the traditional method of vapor barrier behind substrate. You said in theory the shower should be a waterproof box you can fill with water and not leak. Will the holes punched into the vapor barrier from the stapes and substrate screws cause some leakage thus getting to the wood?
Thanks.
Hey Ed,
Short answer: No.
Longer answer: As you staple or screw the fastener through the liner it will push the liner out of the way of the fastener, causing it to pucker. When the backer is attached directly to the stud it will contact the high points of the pucker, essentially creating a round ‘dam’ of sorts around the fastener. As water runs down the wall it will run around this dam, or pucker, rather than into it and into the wood.
hey roger,
quick question,, for the curb, Do u use Mortar mix, or Sand topping mix like the bed??? thanks in advance, i wouldnt have been able to do this without your help,, so far it looks awesome
Hi John,
Wet mud. It’s deck mud with 1 part powdered masonry lime to make it sticky.
what kind of masonry lime? lime morter, hydraulic lime, hydrated lime..i cant seem to find a place that sells it,, home depot, lowes,they dont carry it around here.. what else could i use. morter mix?
Hydrated masonry lime. You can also use quikrete stucco base mix rather than wet mud.
is the quikrete stucco base just as good?? i can buy this at lowes here.. i did find a place that sell the masons lime but they want $50 for a 50lb bag. the stucco bag is $7.. whats the difference in both products? thanks again, i owe you a beer!! or a couple!!
For the purposes of a shower curb yes, it’s just as good. The difference in what products? I don’t understand your question. Masonry lime is just that – the lime. The stucco base mix is the cement, sand and lime all in one mix. You don’t use it in place of the lime in the mix, you use it as the mix.
Hey Roger, I just bought your manual and I have a ?. Im actually taking a tub out and am going to try to build a shower. But the tub im taking has the drain all the way to one side. So my ? is about the pre slope. I know you said to make the perimeter even all the way around but im thinking by the time I get to the drain it will be a drastic slope. So I was wondering if it was posibble to start from the farthest edge and just make a slope towards the drain from there(hope that makes sense).
Hey Will,
There will be an extreme slope on the drain side. If you want to you can just have it at 1/4″ per foot all the way around, but the perimeter won’t be level. It’s not a big deal but it will be noticeable.
Thank you for the quick response, ill try my hand at thid build tomorrow.
hey roger,
quick question for ya… you say to put pea gravel or tile spacers to cover up the weep holes so the deck mud doesnt fill the weep holes in, but you never said when do we take them out!!! i did the pre-slope, liner,an now im ready for the last layer of deck mud..if i cover them with deck mud how can i remove them when the deck mud will be hard as a rock..?? thanks for your help, this site really helped out!!!
Hey Johnny,
You don’t take them out, they stay in there as a permanent part of your mud deck.
Roger, followed you every step of the way and you have not led me astray. Final mudbed and drain height question(s). In Part 4 measuring drain height for top mud bed to 1 1/4 to 1 1/2 inches, do you actually pack the bed below the top of the drain to accomodate for tile and thinset thichness OR do you pack the mud to the top of the drain and then unscrew the drain to the height of the tile and thinset ? Can you screw around (no pun intended) with the drain height after the top bed is set to fine tune to the tile height? If so you can only go up in drain height …correct? And if so, won’t unscrewing the drain cause a void between the top bed and the drain.
Hey Mike,
If you make sure to unscrew the drain before the mud fully cures then yes, you can raise it to meet the tile if needed. It’s always a good idea to do that anyway, just to be able to make adjustments. I normally do the top mud deck just a tiny bit over where the bottom of the tile will sit, so it sits the tile thickness beneath the top of the drain.
Hi Roger, I recently installed a stall shower with rubber liner. I mixed Quikrete sand topping mix that has the portland cement already mixed in. It cured for 2 days, and now in some spots the surface seems like loose sand. Is this a problem for when I go to lay down my tile floor? Not sure what this could be…HELP!…Paul
Hey Paul,
It’s supposed to be a bit sandy. It’s fine.
Roger,
Do I use the same slip sheet/lathe/deck mud as described in your manual to cover the curb or is hardie backer recommended.
Jerry
You can use either if you’re using redgard.
I used a brick curb on a concrete floor. What is the best way to attach the liner to the curb?
Hey Brian,
Bend wire lath into a ‘U’ shape and fit it over the liner on the curb. Cover it with wet mud, let it cure, then tile right to it.
Roger…Thanks a million for your site…9 months into a DIY full bath addition and all that’s left to do is the tiled shower shower. Two questions for you 1) How much time do you have to work the deck mud (your mix 5:1 sand to portland) ? 2) Since this was new framing I got a tip to leave a space between the corner studs to tuck the membrane corners in there (no trifold corners) and avoid the chiseling and run 1/8″ strips on studs to membrane…your thoughts?
Hey Mike,
1. About an hour or so. The first 20 minutes is when it works best.
2. That will work fine. It’s easier to shim out the studs and tuck the corners than chisel.
Very helpful site Elf! Wanted to know if 5-1 portland mud will adhere to itself or as you mentioned I think………. do i need to patch any hardened seem with with thinset? large multi day floor job so seams unavoidable.
Hey Al,
What you are describing is called a cold joint. You need to use thinset to bond the new stuff to the old.
Can I use garden lime instead of masonry lime
Hey Vinny,
Nope, won’t work. You need mason’s lime. It’s normally sold in the concrete section.
Hi Roger, I had another question for you regarding the transition from the tile shower to the rest of the bathroom. The shower cement board will be next taped to the drywall next to it that goes around the rest of the bathroom.
How do you waterproof the edge so that the moisture from the cement board doesn’t get pulled into the side of the drywall? Is thinset enough to stop it?
Also, how do you run the vapor barrier at the edge of this transition so that water doesn’t run from the vapor barrier into the drywall? Do you just give it a lip and protect the edge of the drywall with it?
Hey Eric,
You can silicone the edge of the barrier to the back edge of the backer and put a bead of silicone on the edge of the backer between it and the drywall. That is normally not needed, though, water will always run straight down – not sideways out of the shower. But it also never hurts.
Thanks!
Hello Mister Rogers, You make each day a special day. You know how, by just your being you. (I don’t know if you got the mister rogers neighborhood quote or not) ok onto the serious crap.
this question regarding: When using a liquid topical membrane (redgard) on a shower floor? Ok so I have the presloped deck mud installed now do I apply redgard directly over that then tile, or do I first apply a scratch coat of thinset over the deck mud then redgard then tile. I ask this because it does not seem as though the regard will bond properly to the sandy and gritty deck mud.
(p.s. I used the sand and topping mix and extra sand for the deck mud per your instruction, but you had typed that you didnt know for sure the amount of water you add, so me being the OCD being I am, measured, and it was just shy of 1.5 gallons of water per 90 lbs. of deck mud mix, this amount of water seemed to work perfect and did not shrink when curing, but what the heck do I know, at least this’ll remind you to measure it next time you do it and update that article)
thanks in advance mister rogers neighborhood.
Colin
also just wondering if you wanted more pictures of peoples work for your website, as i am documenting the progress of my shower.
Coolin
Of course, I’ll always take pictures people send.
(I really need to update that page…)
Hey Colin,
Of course I got the reference – Fred was the SHIT back in the day!
You can do it either way. If you skim the mud deck with thinset and let it cure it’ll give you a better surface to apply the redgard. That’s usually easier and uses less redgard as well.
And thanks! I will measure it Tuesday on my next deck.