How to Create a Shower Floor – Part 5

by Roger

And the rest . . . :D

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.

Completed shower mud bed
Completed shower mud bedClose up of shower mud bed

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.

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Paul

Roger,
Thanks for the information. It’s invaluable for new homeowner.
I have a question regarding the placement of my cement board after the last mud slope is finished. Should it go all the way down to the mud, as in, making contact with it? Do I leave a small gap and caulk to fill? Does it even matter? I can seem to find a definitive on this anywhere, just lots of opinions!

Thanks,
Paul

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Phil

Roger – Basement shower (concrete floor w/ builder drain rough-in). I drilled out 1/2″ depth around the drain pipe to allow the drain base to sit below the floor a bit. That meant a thicker than usual pre-slope – 2″ at lip of drain base. Liner went in just fine and flooring will be 3/8″ marble tile. I want to cut back on the depth of the mortar layer (say to 1/2 – 3/4″ deep) to avoid having the finished floor be excessively high above the bathroom floor. When screwed down all the way, the barrel/strainer is 1″ above the clamping ring, so I think the math allows a thinner mortar layer. Is there a structural or code reason why the mortar layer is recommended to be 1 1/4″ min? Another thing: using Durock on walls/ceiling, 16″OC studs and Durock screws about every 4″ to support marble tile weight. Mesh taped seams and 2-3 coats Hydroban over the whole thing. Is this design sufficient for 12×12″ marble on walls AND ceiling? Thanks!

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Roger

Hi Phil,

You can get away with 1/2″ – 3/4″ at the drain for your top slope. 3/4″ would be better, but 1/2″ will suffice if need be. Yes, your substrate as you’ve described it will be fine for both walls and ceiling.

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Garth Brocking

Hi Roger,

As I’m waiting on my bench question response – I just read Part 5, and it says “ensure that the line of the floor is straight from the wall to the drain” that implies you are making that finished layer level. I think you may not have been as clear as you want!! Are you implying that you want the thickness to be the same – but still have the same slope to the drain. Please correct me if I’m not understanding your instructions.

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Roger

Hi Garth,

The finish layer will not be level if your preslope is already sloped, as it should be. The edges of the preslope sit 1 – 2″ higher than the drain (depending on your shower size), so it’s sloped. If you place a consistent 1″ thickness of mud over that from the wall to the drain, in a straight line, it will still be sloped 1/4″ per foot.

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Matt

Hi again,

I just wanted to clarify a point or two in my original post. When the tile was easily pulled up, it was because the thunder came up with it taking a varying later of the deck mud. I also found I wore a depression down to the liner from my walking on it and some minor brushing away of debris.

Matt

Reply

Todd

Roger,

I just wanted to say thank you for time and effort put into this site. I’ve found it to be the most comprehensive on the web as it applies to shower mud pans. I’ve followed your steps to a successful shower install! :rockon:

Best of luck, and I’ll recommend this site to anyone that asks about this type of installation.

Thanks again!!

Todd

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gerry

Hi,
thanks again for all the help! One thing I’m still wondering about, how do we secure the membrane to bricks if we are using them for the transition on a cement slab shower install? Do we need to put backer board over the bricks and membrane?

thanks
Gerry

Reply

Roger

Hi Gerry,

No, you use the lath to wrap over the curb and liner, then the mud on top of that. Once it’s cured you tile directly to it.

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G

Roger,

Thanks to you the curb has been built, shower has been constructed with Hardiebacker (and some screws and such), water proofed with Regard, and it just passed the 24 Hour Flood Test with Flying Colors.

So now the fun begins, but I have a question on the ACTUAL tiling of the Shower. We are using Travertine for the everythingr, including the ceiling. Since there are no “Bull Nose” pieces to use at the edge of the bench, how should I proceed? Also, what about at the top edges of the curb? I was thinking of mitering the pieces, but the stone does not want to make a perfect cut, even after I filled all the holes in the back and let it dry. Not to mention there would be a compound miter cut which would not be easy with my saw.

Anyway, should I just make the top the widest point, and have it overlap the sides? Only have a 1/16th grout joint, so its not like you can see much, but obviously the side of the travertine is not honed, so it does have a different look.

Hopefully you are not on vacation, or not feeling well, as I could really use some help on this ASAP. Typical client, we want it yesterday, we want it free, and we want it perfect. I will be sitting in the corner with my “sippie” cup full of Chardonnay because I am sure this comment is making me sound like I should be.

Cheers!

G :bonk:

Reply

Roger

Hi G,

You can actually just overlap the top over the sides and grout it all. It’ll look completely normal.

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Manuel Gonzalez

Quick question, should I embed my Hardie backer, or should I install my Hardie backer above my deck mud?

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Roger

Hi Manuel,

If I do topical waterproofing, I embed it. If I do traditional waterproofing I leave it about 1/4″ above the top mud deck.

Reply

Dom

Hello,

Could you very briefly describe the difference between the two, or direct me to where it has been discussed? Also, besides the difference in how you install the backer board, does traditional vs topical have other implications for the overall shower pan install?

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Roger

Hi Dom,

With a topical membrane the waterproofing membrane has to be a solid, continuous coating from the wall onto the floor, so I have the backer embedded into the mud to give me continuous, solid backing for my membrane. With a traditional waterproofing the bottom of the board is bare – it will wick water UP. Although there is a vapor barrier behind it and it won’t make a difference, I simply prefer to have that gap in there to prevent it.

On the right side of the page you can enter your email and the elves will send you a free downloadable pdf which explains, in detail, the difference between the two waterproofing methods.

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Dom

Here’s my dilemma. I’m planning on using Hardibacker backer board with redgard topical waterproofing over it. I intend to build a traditional shower pan (tar paper, galvanized mesh, pre slope concrete layer, waterproof liner, top concrete layer).

From here, I am trying to determine:
1) Do I need a moister barrier behind backer board? Is this overkill? Does this have the potential of trapping moisture between topical moister barrier at front and the moister barrier behind the substrate?
2) Should I embed backer board in top concrete layer, or position it slightly above concrete layer?
3) Should I apply topical moisture barrier (redgard) over the top concrete layer in a traditional pan, or does this create the potential issue of trapping moisture once again?

Thank you very much!

Reply

Roger

1. No, you do not want the barrier behind it if you use redgard on the walls. It will actually create problems.

2. No, you want it above the mud bed, for the reasons I mentioned above.

3. No, that creates the same issue as the walls with the vapor barrier behind them.

Reply

Kev

Hi Roger, you are the best! My wife and I would not have had the courage to tackle this intimidating project if not for reading your manuals. We appreciate it!

A couple of comments/questions…..

We have put in our shower curb on the basement concrete floor using bricks.

We created our pre-slope and it seems to be sloping all the way around, though not consistently 1/4″ per foot (all of it is a 1/4″ or more, but no less, and we are hoping this is ok).

We are putting out liner in now and we think we will be ok there.

2 things I didn’t get:

#1 ~ Once we put our top layer mud pan in, can we let it dry for MORE than 24 hrs while we do the endless search for tile?

#2~ What are we laying our tile with; just use the thinset that we use on the walls, or something else?

I appreciate your time..

Thx, kev

Reply

Roger

Hi Kev,

Unless your shower is a perfect circle with the drain in the center you will always have 1/4″ or more slope.

1. Yes, it can cure for as long as you need before tile, provided you’re not stomping all over it.
2. Your regular thinset that you use on the walls.

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Melanie

Hi Roger,

My husband and I are weekend DIY-ers and this is our first time building a shower pan.
I think we mixed our deck mud slightly wetter than yours…it was just wet enough to leave a moist residue on my hands. I packed it in really well, but I’m worried that I didn’t do a good enough job of smoothing it out after packing it down. Most of the area looks like your pictures, but I think we’ve got more ‘sandy patches’, especially at a couple spots close to the drain.
I know you said it’s normal for the mud bed to have a sandy finish, but we’re a little concerned that ours is too sandy in certain spots and the floor tiles won’t have a solid enough surface to bond to. Is it easy for the surface to finish too sandy? Would this be problematic for installing the floor tiles and if so, is there something we can do to improve it at this point before laying the tile?

Thanks for your help.

Reply

Roger

Hi Melanie,

Lack of thorough mixing would be the only thing that would give you sandy patches in only certain areas. You can skim-coat over the entire pan with thinset, let that cure, then install your tile (or waterproofing). It should be just fine unless it’s actually the density of a pile of sand (no bond together at all). In which case you can remove those parts, go over it with some thinset to bond and pack some more deck mud into those areas.

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Joe mc

Sorry roger figured it out. Makes plenty of sense now.

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Joe mc

Hey roger thanks for all the help had a question…..

When doing the top final layer of the base do you still need to ensure the slope of 1/4″ to a foot? You mentioned that since you did the preslope you don’t need to but if you have everything leveled from a 2×4 on top of the drain can that cause problems if you mud up to the bottom of the drain top if its only 1/4ish depth from top lip of drain to bottom lip of the drain. So say mine is a 3 foot length but I only drop a 1/4″ since I mud right up to the bottom of the drain? Sorry if this doesn’t make sense

Reply

Roger

Hi Joe,

Yes, you still need that slope. What I mentioned is not needing it to be thicker on the perimeter. If you have a proper preslope in there your top slope will be a consistent thickness, you’ll still have the 1/4″ / foot.

Reply

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