To create a shower floor from scratch we use what is commonly referred to as “dry pack mortar” or deck mud. Deck mud contains three ingredients: regular portland cement, sand, and water. That’s it. Don’t let anyone tell you that a latex additive or anything else is necessary. It is not. Properly mixing and installing deck mud will create a shower floor that will last for years and years.

The ratio is very important to achieve the correct consistency and stability. You want 5 parts sand to 1 part cement. Your ratio can vary from 4 to 6 : 1 but the 5 : 1 is what I use and find to be the easiest to work. You want just enough water to dampen the mixture. It’s not a lot. Too much water will cause your mud to shrink as it cures and compromise the stability of your base. You just want it damp – really.

The easiest and most convenient way to get your mixture correct is to buy the quikrete “sand and topping” mix which is sold at all the big home centers. This is already mixed at a 3 : 1 ratio. For a 60lb. bag you need only add 30lbs. of sand to it. This is how I mix mine – it’s convenient. The easiest way to mix it is with a regular shovel or garden hoe in a mixing box or regular wheelbarrow, although you can mix it with and in anything that works for you.

After it’s mixed it should just be damp. When you pick up a handful of it you should be able to squeeze it without water dripping from it. It should be able to hold it’s shape when you squeeze it, just like a snowball.

Whether you mix the entire batch from scratch or use the sand and topping mix it should all have this same consistency. If it is any wetter it will shrink as it dries and it will not be as solid and stable as it should be. I usually start with about 1/2 gallon of water and work up from there. I think. I really can’t tell you exactly how much water to use because I don’t measure it. I’ll have to do that and include it here.

As you install and shape your base, slopes, and shower floors you want to pound the mix with a wooden or magnesium float. I mean beat the hell out of it. You want the mud packed very well with no voids. The harder you pack it the more stable it will be. I have or will have individual posts to instruct you how to shape shower floors, etc. This one is strictly to describe the proper recipe for your mix.

A couple of companies also make a mix specifically for shower floors and mud beds. I’ve only used one and it worked quite well. Just follow the mixing instructions on the bag and start with the minimum amount of water they suggest and work up from there.

When set (about 24 hours) the mud bed will be a perfectly suitable substrate for your tile installation. It will be sandy on the top. You can scratch it with your fingernail – stop doing that! It’s normal. I understand it’s counter-intuitive, but it really is normal.

Although you may have been led to believe that creating a shower floor from scratch is a very difficult thing to do, it is not. With careful planning and attention to detail you can create a shower that will last for years without any problems. Getting your mud mix correct is at the core of the proper method.

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Leave a Comment

  • Scotty

    Hello, great info here! I am doing a custom size pan using deck mud. I have a 18″ hole around drain 5″ or so deep.can I just backfill with deck mud? I also have a liner drain. Can I do preslope redguard, final slope more redguard and tile? thanks much!!

    Reply
    • Roger

      Hi Scotty,

      Yes, you can fill that with deck mud. If you use redgard it just gets a single slope with redgard over the top of it.

      Reply
      • Scotty

        Thank you! I know it takes your personal time to help us and I really appreciate it! The clamp liner drain is okay? Installing with gravel for weep holes and deck mud as normal with one slope? This is a great place to learn some tricks. I normally use several sites for my projects. I have abandoned all but this site for shower construction! You have definitely saved some people from leaky showers!! There’s lots of wrong info on Google, glad I found the floor elf…..

        Reply
  • Tomás

    Floor Elf, your site is a godsend. Question: I did a traditional pan–presloped mud over tar paper on sub floor, then oatey PVC liner, then ~1.5 inches of more deck mud on top. It seems really soft–i can scratch it with my fingernail, if I sweep it the plastic bristles remove more fine sand from the top layer. If I use a wet sponge I can remove material really quickly, almost like drywall joint compound. Should I worry or is this ok to tile over?

    Reply
    • Roger

      Hi Tomas,

      It is fine to tile over, it’s supposed to be sandy. If you want it a little more solid before tiling you can always soak it down with a spray bottle and let it sit overnight. That will reactivate some concrete on the upper layer and solidify it a bit.

      Reply
      • Tomás

        Phew! Thanks for putting my mind at ease. If you are doing Kerdi Board walls with a traditional shower pan, how do you prefer to handle the joint (where the Kerdi board meets the deck mud)–bead of silicone, Kerdi fix, or Kerdi band onto the floor, or…?

        I had planned originally to do Hardie backer on the walls but my research (especially your site) convinced me to change after I had done the pan.

        Reply
        • Roger

          I normally do kerdi-band to the deck, but it’s really not needed since the liner goes up behind the kerdi-board and the board doesn’t wick water.

          Reply
  • Bob Payne

    I’m building a shower pan. I’m planning on using portland/ sand mud, form my preslope, rubber membrane, then finish size with mud bed. I will not be
    installing tile, rather epoxy coating like used on garage floors. Any issues with this???

    Reply
    • Roger

      Hi Bob,

      I wouldn’t try to install the epoxy over the mud bed itself. I would likely coat the finished mudbed with straight concrete. A mud deck is extremely sandy – it’s supposed to be. I don’t know how much that would affect the epoxy coating.

      Reply
  • frank

    sakrete sand mix documentation says when you use it as dry pack, it must be tiled the following day or else you must wait 28 days. what’s up with that??? Quotation: “Note for tiling: Tiling should begin within approximately 16 hours of the mortar bed installation. After 24 hours, the mortar bed enters a green state and should not have tile adhered to it for 28 days.” http://www.sakrete.com/blog/creating-a-mortar-bed-for-a-shower-installation-using-sakrete-sand-mix

    Reply
    • Roger

      Hi Frank,

      Sakrete is covering their ass – for people who don’t mix it correctly with sand. Any concrete product has a 24 hour initial cure and 28 day full cure. Between those times it is ‘green’. If it is a pure concrete slab (which is what uninformed people do – don’t mix it with sand, and why sakrete is covering their ass) it can curl during this time. If tile is bonded to it when that happens it will cause problems.

      If you mix proper deck mud this is not an issue.

      Reply
  • B. Larson

    I was advised by a big box store to use quikrete mortar mix for my shower pan, now I know I shouldn’t, it’s too late to return it, any way I can adjust it for it to be suitable for the deck mud layer over the liner?

    Reply
    • Roger

      Hi B,

      Mortar mix can not be used in any way to form your shower pan. Sorry.

      Reply
  • John

    As far as I know this is unnecessary because if water gets through the tile through the thin set through the deck mud it will hit the pan liner and your pre-slope will make it drip to the drain

    Reply
    • Roger

      John is correct, and it can actually lead to mold if and when water gets trapped between the two waterproof layers – which it will do through the weep holes if you seal the top of the mud deck.

      Reply
  • mike

    Hi Roger,

    Your patience must be without end to answer all these questions, much appreciated.
    I was wondering if you have a jig or something to cut the metal tile edge strips that helps make the corner look good. Seem difficult to get a nice corner with the metal.

    Reply
    • Roger

      Hi mike,

      I use a small miter saw with a metal blade on it.

      Reply
  • Luke

    I am still confused on the deck mud, I thought I could use type n mortar for a shower pan. I see I previous comment where it looks like you advise to use deck mud over the mortar. I’m sorry to best a dead horse but I could use clarification.

    Reply
    • Roger

      Hi Luke,

      The previous comment was likely about going over an existing preslope made from type N. Any and all layers of your shower floor should be constructed using deck mud.

      Reply
  • Tim

    I’m considering deck mud to level a 100+ year old concrete basement floor. We have a new french drain type drainage system in place, but the old slab is not flat – up to two inches of variation. Since I want to finish about 800 sq ft, self-leveling compund would be $$$$$ and a new slab of concrete seems like overkill.

    Do you think dry mortar with a vapor barrier underneath would work in this situation? It’s just going to be covered with vinyl plank. It shouldn’t get wet, it’s low traffic and it’s not going anywhere.

    I almost feel like I could fill with gravel and put down a layer of OSB, but i want something more stable.

    Reply
    • Roger

      Hi Tim,

      If by ‘dry mortar’ you mean deck mud then yes, it should work perfectly.

      Reply
  • Monique

    Hi there
    I have just purchased a property with a full tiled bathroom with a walk-in tiled shower.
    I have found a leak in the bedroom next door which is coming from the shower next door – where the wall meets the floor.
    I have taken the gib/wall liner off in the bedroom and done a water test to find this.
    There is a gap between where the wall tiles meet the floor tiles (the height of the floor tiles is higher than the height of the foundation concrete floor in the bedroom and the rest of the house because of the tiles being stuck on top). Silicon has been stuffed in here but it’s obviously not working.
    There is no liner or any sign of a waterproofing membrane.
    After removing the wet silicon to dry the area out + remove and replace the bottom floor plate for the wall, I am able to push 10 pieces of paper through from the bathroom in to the bedroom through the gap.
    I am not able to do a full bathroom renovation at this stage and need a solution to:-
    1) fill the cavity/drop-off/gap so that water can no longer sit in here and roll under the timber framing and into the bedroom next door.
    2) best waterproofing solution for this dodgy installation?
    3) can I fit a shower box over the top of the tiles and stop any future leaking?
    Please note that I do not know anything about tiles and if products are recommended I will have to go to a tile shop and get.
    I can’t get anyone to come in and fix it due to extremely tight weather proofing regulations here in New Zealand now. Everyone’s recommendations is to rip the bathroom out and start again except I am not in a position to spend that kind of money right now.
    Your advice would be much appreciated;-)
    Email: monique@plantcare.nz

    Reply
    • Monique

      Can I:-
      Staple some waterproof liner onto the back of the cement board that the tiles stick to from the bedroom side,
      Then tuck this under the bottom of the tiles wall and flap it out over the edge of the tiles.
      Then point a tile floor mortar into the cavity/gap from the bedroom (I would need to take the bottom wall frame off that I have just replaced which is fine as I have constructed this in 3 sections that I can currently move in and out for access purposes) and press the mortar up to the floor tiles so that the liner can be cut to curve and sit on top of the mortar and almost up to the level of the floor tile. The method to my madness is to create a barrier that encourages any water backninto the tiles and into the sloping drain.
      Then waterproof membrane the tile mortar from the bedroom side and also through the gap in the bathroom by carefully lifting the liner.
      Then use more waterproof tile floor mortar (what is epoxy grout and is it waterproof and could this be a substitute for the mortar?) as a grout on top of the liner and to seal up the front of the gap.
      And last but not least, then put a liquid waterproofing liquid over the top (I am a landscape designer and we use a product over concrete to make it waterproof for fish ponds etc).
      Last question: how do I protect the rest of the tiles if this all works? Do I just clean the grout and then spray a grout protector over the top of the grout lines? The shower looks fine, it’s just the dodgy workmanship underneath that you can’t see. Thank goodness the rot has all been replaced.

      Reply
      • Roger

        NO. :D No matter how you waterproof that gap, it sounds as if nothing else below the tile floor is waterproofed. That means that the water you can see seeping out will simply find another place to leak out once you cut off that exit.

        Reply
    • Roger

      Hi Monique,

      The ONLY solution is to remove at least the floor and bottom row of wall tile and install a properly waterproofed base. Not sure what a ‘shower box’ is, I’m assuming an acrylic product which covers the walls? In any case replacing that floor with one that is properly waterproofed will be much cheaper than trying to do that.

      Reply
  • Jon Campbell

    I did a preslope with Mortar mix at the recommendation of a big supply store employee now Im reading your stuff and am worried, should I proceed with my liner and just use the portland mix on the final mortar bed or maybe try a small layer of over the mortar mix bed? Any recommendations on proceeding?
    Thanks!

    Reply
    • Roger

      Hi Jon,

      You should be fine with the preslope. Just use regular deck mud for the top deck.

      Reply
  • Roy

    I poured and packed my shower pan 3 (using a 5:1 ratio) days ago, and it still has not cured? I know its cold in Michigan right now, so starting on the second day I began running a heater in the room. Today it is still not dry. Can you think of why?
    Thanks,

    roy

    Reply
    • Roger

      Hi Roy,

      Is it hard? I know that’s a weird question, but there’s a reason behind it. :D

      Reply
  • Loc

    Hi I’m trying to pour the shower pan can I use 60 sakrete sand mix for topping and bedding plus 30 lbs of sand instead of the 60lbs quickrete plus 30 sand? Thank you very much for this website.

    Reply
    • Roger

      Hi Loc,

      Yes you can.

      Reply
  • Michael R

    Will play sand work?

    Reply
    • Roger

      Hi Michael,

      Yes.

      Reply
  • Raffoul Ajami

    HI Roger, I need to find a way to make my mud deck pre-slope (to be covered by a plumber liner) light in weight, its a a large shower that a builder hired us to do, and its on the 2nd floor with one (1) sheet of plywood over joists that are 24″ on center, (i know oh my God) and I cannot find any major setting material manufacturer that makes light weight shower mud, there’s dozens of light weight setting material on the market but not for mud deck, what ever you can help with it will be greatly appreciated and thank you for great articles.

    Reply
    • Roger

      Hi Raffoul,

      Oh my god! :D

      Use perlite rather than sand.

      Reply
  • Nick

    Hi Rodger can I or should I put a layer of waterproof membrane on top of my dried mud bed then tile and grout, or is it not needed. I will be using the kind you just roll onot with a paint roller

    Reply
    • Roger

      Hi Nick,

      If you don’t have a liner beneath your mud be then yes, you need to waterproof it. If you do, then no.

      Reply
  • Jose

    Rojer, I’m a little confused about the ratio when mixing sand with Portland cement. When you say 5 to 1 ratio, do you mean for every 5 pounds of sand, one pound of Portland cement has to be mixed? Great website.

    Thank you.

    Reply
    • Roger

      Hi Jose,

      That is correct.

      Reply
    • Jonathan R Hammon

      Or any other unit of measuring, teaspoon, cups, Oz, quarts, shovels, lierall5any type of a container. It’s 5 parts, whatsoever they are, sand to 1 parts cement

      Reply
  • Kevin Link

    You mention the mud should be sand and regular portland cement. I heard that “Sharp” sand was the best, do you have a preference for sand type?

    Reply
    • Roger

      Hi Kevin,

      Sharp sand is best, but difficult to come by in some areas. I most often use the regular quikrete sand sold right next to the sand and topping mix.

      Reply
  • James_morrell

    Hi. I have a space from the deck/base to the bottom of the wall. Do I do the deck mud first and come back after it is dry and fill in the wall space with deck mud

    Reply
    • Roger

      Hi James,

      You can if you want to.

      Reply
  • John

    I only have 1/4 inch between my hardiebacker shower floor and the top of the bottom flange. This means that my preslope will only be 3/4 of an inch at the wall and 1/4 at the flange. Will that work?

    Reply
    • Roger

      Hi John,

      Yes, that will work fine.

      Reply
  • Jay

    Do recommend “Play Sand” or “Multi-Purpose Sand” for the 30lb mixture ratio to the 60lb Sand Mix?

    Reply
    • Roger

      Hi Jay,

      The multi-purpose.

      Reply
  • CountriSquire

    Hi Roger,

    Plenty of You-Tube and just finding your site and it looks like the best yet across the baord.

    Admittedly, I haven’t read the plethora of info yet, but can you take a quick jump to Chapter 10?

    I’m doing tub to floor shower conversion on concrete slab home. I’ve removed concrete and dug well below to make the P-trap location 180 degrees opposite and the finished new shower drain will now be about two feet inward.

    I’m thinking the surface of the flange that will be below the ‘membrane’ should be located about 1-1/2″ above existing slab floor when I plumb it.

    1) Does that sound correct for ~ 3/4 thickness on pre-slope and the same for the mortar bed above. Or should I allow 2″ to 2-1/4″ to allow for thinset and tile thickness as well? Tile not yet selected.

    2) When the plumbing is done and the hole back filled should I fill the entire slab opening thickness with concrete or mortar? Now aprox. 14″x 28″ or so – this includes old area where tub drain came up ~ 2″ out from sill plate.

    3) If using bricks instead of 2×4’s for curb, how does one secure the membrane on the top and outside surfaces of the bricks?

    Let’s leave it at those three for starters, but maybe more as read the pdf’s.

    With all the bucks involved, a re-do is definitely notan option.

    With the sincerest of thanks!

    Reply
    • Roger

      When you say the ‘surface of the flange which will be below the membrane’ I assume you’re speaking of the lower flange? I also assume you’re using a regular pvc membrane and a double layer shower floor? If so…

      1. You want the lower flange to the the depth of your preslope. So 3/4″ high. The membrane gets sandwiched between the upper and lower flanges, then the barrel threads into the upper flange – that is what lowers or heightens your drain for the finished surface.

      2. It can be concrete or deck mud, either one works.

      3. You wrap the membrane over the curb, then bend wire lath in the shape of the bricks and fit that down over the top of it. The lath holds the membrane in place.

      Reply
  • Tuan Huynh

    Hi great site by the way !
    I try to build my shower and I going to use schluter foam

    I have 2 questions
    1st can I cut down a schluter foam ?because I like it’s lower
    2nd how do I make it bonds to the concrete ?

    Reply
    • Roger

      Hi Tuan,

      Yes, you can cut it down but it will be difficult to get it consistent. It is installed with thinset.

      Reply
  • Tom

    Now that mine is installed, what is wrong with not having a pre-slope between the liner and top layer? Hopefully not much! Thanks for your time.

    Reply
    • Roger

      Hi Tom,

      There will be a layer of water that sits below the drain itself. It will NEVER drain, and it will be there permanently. A cesspool for all sorts of nasty things to grow.

      Reply
      • Kamran

        Can you elaborate on the preslope? What does it meant and where will the water sit? In our implementation we have plywood, then cement board, then shower liner and then the mud pan that is sloped. Does this work?

        Reply
        • Roger

          Hi Kamran,

          I already elaborated on it here: Shower floor for tile If your shower liner is flat on the cement board, without a slope beneath it, then no, it doesn’t work. You need a preslope beneath it.

          Reply