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.

{ 322 comments… add one }

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  • Steve Tower

    Great information! Been reading and learning what I can to be sure and get mine right.
    Question: traditional PVC liner between preslope and final mud bed… Durock CBU backer board dropped down to mud deck leaving a gap of 5/16” or so, I see you reccomended a “urethane” bead of caulking between that gap. I’m wondering if I do that, how does any water that might get behind backer board and to the vapor barrier against the studs running down the wall get past that urethane caulking? Wouldn’t it build up there and need to come through the backer board to get out?

  • Lisa

    Thank you so much for all of this information. I have seen conflicting tutorials on what to use for the top mortar layer (either dry pack of sand/topping mix+sand, or mortar mix). Are there pros/cons to each? Why do you prefer the sand/topping mix for the layer above the shower pan liner? Thank you.

    • Roger

      Hi Lisa,

      There should be zero tutorials that recommend mortar mix. It is absolutely incorrect.
      The top deck needs to be able to drain water efficiently, which means water needs to be able to flow through it freely. Deck mud accomplishes this (the sand mix + sand), mortar is too dense and requires more inflow of water before the existing water in the deck will drain through. This means that with mortar your shower floor will NEVER dry out, it will constantly retain water. This leads to mold and all sorts of nasty things. With deck mud the gravity will pull the water out of the deck down to the membrane, then to the drain.

      • Lisa

        Thank you so much! Exactly the information I needed.

        • Roger

          My pleasure! :)

  • Mike Tursellino

    I’ve read this over so many times. Very descriptive and seems to me the best procedure online. I see some say not to embed cement board in top layer like your diagram but you also mention that you can embed it. If embedded do I need to worry about water wicking up wall? If I leave it above the final mud layer do I need to worry that the cement board floats at the bottom since screw are placed above liner? Also can either way be done without use of redguard type membrane as log as barrier placed behind cb? Thanks in advance!

    • Roger

      Hi Mike,
      My general rule is that if a topical membrane is being used (redgard or kerdi, etc.) then it’s fine to embed the backer. If I am going with a traditional system with the membrane and two layer base I leave about 1/2″ above the top deck.
      Cement board will wick water. No, you don’t need to worry about the very bottom not being screwed in. It’s stiff enough that it will stay in place without issues.

      • Mike Tursellino

        Thanks again. that cleared up alot of internet conflicting methods…Have another question though. I am building the shower on a wood floor. The house is from the 30’s ,subfloor is 2×8 16″ oc (probably overspanned) with shiplap diagonal subfloor that has shrunk over the years. What extra bracing do you suggest? I was going to add another layer of 3/4 ply over the top of the shiplap and maybe some 2x cross bracing underneadth. Or should I cut out the shiplap? any suggestion is greatly appreciated

        • Roger

          The plywood will be enough to shore up that floor for tile installation. The 2×8 16o.c. is a VERY sturdy floor. Leaving the shiplap and installing the 3/4″ ply will give you more than enough.

  • Sean

    Great info, great delivery too…… cheers

  • Tom

    Thanks, you website is so helpful! Just got to the end of part 5 successfully in my shower build. Would you suggest to tile now, all the way to the liner, and then put backerboard (Hardibacker) above the floor tile. Or is it better to put backerboard first, and then tile? Mahalo!

    • Roger

      Hi Tom,

      Backerboard first, then tile. You don’t want tile beneath your wall substrate.

  • Pat

    Would you recommend Redguard on the finished floor pan before tiling as long as I then tape and seam then redguard the shower walls last?

    • Roger

      Hi Pat,

      If you have a liner in your floor pan then no, do not use redgard over it.

  • Joshua Casteen

    Thank you for all the info. Question though, first I am building a 4’ by 6’ walk in shower on slab foundation. It will be tiled when finished. What changes do I need to the pre-slope or too mud bed if I install a 36” rectangular drain? Or is it just shaping the top mud bed to fit it?

    Thanks for your time,

    • Roger

      Hi Joshua,

      The linear drain will be installed first, then the slope is just one FLAT slope – 1/4″/foot from the drain to the opposite end of the shower (or to each wall if the drain is installed in the center).
      Question: if you are building a 48″ wide shower, why do you have a 36″ drain?