How to Make Deck Mud

by Roger

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.

Previous post:

Next post:

Ron

You mention that the mix should be 5 parts sand to 1 part cement. Some of the other things you say suggest this is figured by weight. Is the ratio mentioned figured by weight or volume. They are likely different. It turns out in our area sand mix is only available in 80 pound bags not the 60 you suggest even though Quiikrete lists it on their web page. I just want to be sure I am getting a good mixture.

Reply

Rich

I did a stupid thing. I installed the pan before the bottom row of Durock was installed. Do I just need to build up pan another 1/2″-3/4″ after I install the Durock or best to remove floor?

Thanks much

Reply

Bill

Hello, im doing a tile shower my floor is a concrete slab i have already installed liner and made my curb i have just put my mud down and it doesnt look right its alot flakey or powdery and when stepping on it it makes little crackling sounds when we mixed it there was a little extra water ..we tried out best to take it out …i used a unknown brand deck mud i tried looking for the quickrete mud but no stores near by carried it please help what should i do

Reply

Justin

Roger,
I mixed the deck mud as directed and needed to pack it in as 3 separate batches due to the size of my shower. There is a crack at the boundary between each batch. I am using Kerdi on top of the deck mud. Are the cracks a problem or will the thinset fill in and be OK or do I have to start over? Would putting down mesh tape like for CBR help?
Thanks for your time.

Reply

Scott Golden

My preslope I did not use thinset over concrete first. I can tell it did bond to concrete. I used quick pitch kit. Should I redo? Getting ready to add pan liner and final mud base.
Thanks for any help.
Scott

Reply

Karl

Hello Roger,
First, thanks for this website. It is a wealth of information that I trust and it gives me the confidence to proceed with my project.

I have a sunken shower on a cement slab that I will soon be rebuilding as it is totally falling apart. For the pan I plan to make a mud base and use the Kerdi system. Also this shower has a horrific step in, the curb is 3.5 inches high and the step down, including curb is 7 inches. I have two questions.

1) I have no idea what is under the current (squishy) mud job, whether it sits on concrete or dirt. After I shovel out the old pan, should the new mud base sit on concrete (i.e. pour concrete up to the desired height) or would having the mud base sit on a bed of freshly packed sand be good enough?

2) I would like to just bust out the curb and just have a walk-in and a step down. Is this feasible? I would like to use a frameless enclosure. How would I keep water from running down the glass door and onto the bathroom floor without the angled curb top? Or should I have a lower curb, or perhaps build up the shower floor so it is no longer a step in?

Thanks again for taking time to help. If you are ever in Jacksonville FL try Bold City Brewery’s Duke’s Cold Nose Brown Ale. Delicious!
Karl

Reply

John freeman

First of all, stop drinking the ale, and you could probably think this one through yourself! I would suggest you dig it all up and start with at least 3 to 4″ of concrete (if this is over sand or dirt). Then simply install your liner and make your 5/1 mix. As for no curb, I’ve done it all the time. Mark out exactly where the glass will go and begin your pitch 1/2″ outside the glass line. Then it all drips inside down to the drain with no curb!

Reply

Dennis

Thanks for the straightforward info. What about coverage? The Quikrete Sand/Topping 60lb. bag indicates about .5 cu ft. of volume. When the 1/2 bag of sand is added, what is that volume? Does it go up to nearly .75 cu. ft or is it less? Can you give an example of how much you use on say a 30″ x 60″ pan (total: preslope and main pan). Thanks!

Reply

Roger

Hi Dennis,

For one bag of s&t and 1/2 bag of sand you’ll normally get about 3-4 square feet of your shower pan.

Reply

Dennis

Your help is great. We have finished the pre-slope using tar paper, wire mesh and 5:1 dryish sand mix. We’ve got a great even slope but the concrete dried with an alligator finish on about 90% of it. Small bumps and crests no more than 1/8″ high. The other 10% dried with the sandy surface just as you describe it should be. We want to avoid this for the top bed so applying thinset is not made more difficult. Any ideas what caused this and should we be alarmed? Thank you for the amazing help.

Reply

John freeman

You may have mixed wrong. Here’s what I do to get a perfect mix: put 5 shovel’s full of sand on a 4 X 4′ piece of plywood. Then add one shovel full of Portland cement. The pile is in the middle of the board. My wife is my helper. I take a flat shovel and shovel under and turn the dry mix as I go around the board and mix the pile. After I go around twice or thrice mixing it dry, my wife follows me on the next 4 to 7 times around with a bug sprayer, spraying water in a mist over the pile as I turn and mix, still going around in circles. The last couple times around I chop and turn fast until it is of a consistency so when I grab a handful and squeeze it together, it forms like a snowball (not too wet though). There is a point where I stop my wife’s spraying and say , “Hold it! Let’s check.” The I simply shovel a good amount into the pan liner and move it around with a 6″ spackle knife to get it even and leveled to what I think is a gentle slope. I use a 12″ level for small shower stalls and 24″ for larger. Then I pound the hell out of it with my aluminum mag (or wood float if I can’t find my mag). Then I use the level to see dips and high spots, and use my spackle knife to shave it smooth. Then I finally rub smooth with my mag. Never ever had I had nothing but a smooth finish, nice and hard, and easily acceptable to thinset. I do try to make my shovel full’s to be consistent in size, not weight.

Reply

Dennis

I don’t think it was the mix. We used the exact formula from the elf and didn’t get it too wet. I wonder if it has to do with not packing it hard enough and having air come up from the spaces in the wire mesh. My helper did keep the surface misted every 4 hours or so for a couple days as she has done with other concrete projects. Would this cause it? Thanks.

Reply

Sarah Baba-Aissa

Hi , I am doing my shower in the basement. we have a 3 inch cement slab, we will add waterproof membrane. After that they recommended us to put mortar mix but Quikrete recommended to put sand /topping mix product on the membrane to create the weight instead of mortar mix. they suggest us toput half Water, half Acrylic

is that ok? we want to put 2 inch layer after that our Tile

Thanks

Reply

Rob

You will need to create a pre pitch with a dry pack mortar before you lay the water proof membrane. First layer is a dry pack creating the pre pitch. Next layer is the waterproof membrane. Third layer is the final layer of dry pack mortar. There are a ton of videos on YouTube demonstrating the proper way to build you’re own shower pan.

Reply

Roger

Hi Sarah,

No, all that is unnecessary. Just use regular deck mud. And you need to create a preslope first, then your liner, then a top slope. Both slopes are nothing but deck mud as described above.

Reply

Ray & BeBe

Like your postings, and your information. clear, simple and not jumbled up will pass it on
Thanks,
“A” Team :whistle:

Reply

Earon

Roger,

I followed your instructions to the “T” and everything turned out great. We just finished applying tile and getting ready to apply grout. our shower looks great. Thanks for this website. It helped me tremendously while rebuilding my shower. Now I am getting ready to build two showers the same way in an investment property we just purchase and will be using your instructions to build the shower pan for them. Again, thanks for the information. :cool:

Reply

James

How thick should the base layer be. To be more specific the layer used to create the slope before the liner.

Reply

Roger

Hi James,

From whatever thickness the bottom of your drain sticks above the substrate up to whatever it ends up at the walls at 1/4″ / foot. So if your drain is 1/4″ from the substrate, your preslope will be 1/4″ at the drain, and if your furthest wall is 4 feet away from the drain, your perimeter will be 1 1/4″ thick.

Reply

Ben

hi,
a quick question, I layed down the second layer of mortar in my shower after installing the pan liner and realized I made the pitch too steep. is it ok to add more mortar to the existing mortar after it is dry?

Reply

Roger

Hi Ben,

Yes, but you need to use thinset to bond the new mud to the existing. Or you can leave it, your slope can be over-sloped, that won’t hurt anything at all.

Reply

jim

building my own tile shower. Installing a linear drain so I presloped my sub floor and put down thin bed of mortar by the drain to get the best taper to the drain. I’m ready to put my liner down and then complete the top mud deck. At the thinnest point,my mortar will be about1/2 to 3/4 of an inch. Is that enough thickness for the mud deck to remain stable or is there a better mixture or product for thinner applications.

Reply

Jay

Can I install the membrane the same day as the preslope? Or does the mud need to cure?

Reply

Roger

Hi Jay,

In a traditionally waterproofed shower you can lay the liner over the preslope right away.

Reply

Bob

It is correct to do two layers correct? One thinner with slope and then lay pan and then another thicker coat?

Reply

Roger

Hi Bob,

Yes.

Reply

Ernest Phillips

I am installing 2 shower floors, one, on wood sub-floor, the other a concrete slab. I am using the Kick-pitch/slope plastic strip kit.
2 questions –
#1 – Have you used that system and any pointers?

#2 – Mud mix – I saw the Quikrite Sand & Topping – how much more sand do you add (30 lbs.?) I’m sure you do not mean weight it, is that like one bag sand & topping, to an additional half bag worth of mason sand? I have an entire truck load of mason sand on site. This mix is so important I want to get it right.( At Lowe’s they sent me to the tile dept. to buy the 4-1 mix at $15.00 per bag, sold by the grout, compared to the Quikrite products in lumber at $5.00 a bag.)

Reply

Roger

Hi Ernest,

1. Not really, it’s fairly self explanatory. It works well.
2. 25 lbs. per 60lb bag of s&t mix. Yes, 1 bag to 1/2 bag.

Reply

Mathieu perreault

Hi, great site by the way ! I have a question about a mortar bed on a concrete slab? Is it the same proces than on a plywood? Do I need a tar paper plus a metal lath? I’ve seen many contractor put some thin set on the concrete and and mortar bed after and membrane! What do you think? Thank you

Reply

Roger

Hi Mathieu,

Over concrete you just put down thinset then the mud over it. The thinset bonds it to the concrete, the same thing that the lath does over wood.

Reply

jeff dougherty

Great info dude, I,ve done a lot of tile but the floor I remember not watching. I am going old timer, as I,m a sheet metal mechanic by trade. I’m fabricating a copper pan then mud and lathe in the pan. That way, I will know the harwood floors won’t be threatened by a bar of soap someday!

Reply

Dave Law

I doing my centre patio. It has a 1″ wooden subfloor. I got a roofer to line it, with the finish being of a gritty texture. This replaced the old metal pan which had rusted out. My next step is to slope quikrete deck mud down to the floor drain, 2″ thick at its thinnest point. Next is redguard, thin set mortar and finally tile. Am I missing any steps?

Reply

Roger

HI Dave,

Not that I can see.

Reply

Nick

Question for you.
I have a shower i am remodeling and will be creating a mud bed from your directions. Right around my Drain, i have a cutout in the concrete slab(I assume from construction of the house) that was backfilled with sand. It extends out from the bottom flange of the drain about 4 inches on each side. when doing my pre pitch mortar bed, what would be the best way to go over that sand? should i first cover the sand in concrete to give a solid ground for the bed to lay on? I dont know how well the deck mud will stick to the sand that has been filled in.

Thanks
Nick

Reply

Roger

Hi Nick,

The deck mud doesn’t need to bond to the sand, you can just pack deck mud into that space, it’ll be fine.

Reply

Kyle

Concrete slab with shower drain bottom flange level with concrete. Can I smear the thinset then deck mud very very thin near the flange then ¼ inch per foot out for my preslope? Or do I need to have a min thickness for the deck mud at the lower flange?

Reply

Roger

Hi Kyle,

You can do it with the thinset and thin bed at the drain for a preslope.

Reply

Michael

i have been on you site for the last 2 days trying to find a way around pulling my pan up and redoing it. long story short I did not preslope under my pvc pan liner. I used Tec thick mud bed directly on top but now I am afraid I will have mold grow in the shower since there is no pre-slope under the liner. Is there an issue that the floor drain flange is flush with the subfloor? it was installed by the plumber prior to me starting on the shower. Thanks in advance.

Reply

Roger

Hi Michael,

No real issue with the drain, but you do need a preslope beneath your liner.

Reply

Leave a Comment

;) :wtf: :wink: :whistle: :twisted: :suspect: :shades: :roll: :rockon: :oops: :lol: :lol2: :lol1: :idea: :guedo: :evilb: :evil: :eek: :dance: :cry: :corn: :cool: :censored: :bonk: :arrow: :D :?: :-| :-o :-P :-D :-? :) :( :!: 8)