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.
Roger,
I took your suggestion and used the Quikcrete Sand/Topping Mix to build a shower base tonight. How soon can I cover it with the Kerdi membrane? Will it affect the curing process if I cover it up too soon?
Hey Dan,
You can do it tomorrow. It won’t affect the curing of the mud deck (it’ll actually create a stronger bed) but it may affect the bond of the kerdi with the thinset. It’ll be ready to go in about 12 hours or so.
Roger,
Was at one of the big box stores today and could not find powdered lime. They sent me to garden section and showed me pelletized lawn lime (http://www.homedepot.com/webapp/wcs/stores/servlet/ProductDisplay?storeId=10051&langId=-1&catalogId=10053&productId=100348791&R=100348791).
What lime product do you buy and where do you buy it?
Thanks,
Mike
It’s type S masonry lime – it’s sold in the concrete section, not the garden section. The stuff he showed you (surprise!) won’t work. Head over by where you bought the bags of concrete – it’s over there.
Roger,
Just a quick question. I’m planning on laying thinset down before I put my dry pack on a concrete shower floor. Should the thinset be setup prior to the dry pack?
Thanks!
Nope, install the mud deck over it while it is still wet.
Roger,
I have a question about building the curb. Do I use the same deck mud recipe (5 parts sand to 1 part cement) for the curb or should I be using something different?
Thanks,
David
It’s a little bit different. You just need to add 1 part powdered lime to the mix. It’s called wet mud. The lime makes it sticky so it will bond to vertical surfaces.
Roger:
In my opinion, you’re right up there with Sal Kahn (kahnacademy). The only difference is that Sal got a megabuck Federal grant to pass along his calculus, whereas you’re doin’ it for personal satisfaction. I’d researched the excrement out of the internet to discover the intricacies of the constuct of a shower base. I stumbled across your site and it was suddenly clarified for me. Like standing an egg on end or doing a heart transplant, it’s easy once you know how.
Again, in my opinion, you should have a PHD in flooring conferred upon you and then be transplanted to the halls of academia so as to distribute your expertise to the ‘great unwashed’.
Thanx, ED
Thanks Ed.
I actually do have 21 tile-related letters I can place after my name, I just don’t because A) It takes too long to type out B) Nobody that is not in the tile industry knows, nor cares, what they stand for and C) I’m not a pretentious jackass, just a jackass.
Thanks for your comment, though!
Roger
NTCA, CTIOA, CTS, CTMS, MASRS
(M-I-C-K-E-Y-…..)
I installed a dry pack floor over lath and 15# felt. Most of it is solid with a slight sandy finish. The problem is that there are patches that are very sandy without any integrity. I need to put marble tiles down and i’m concerned that the tiles will crack or pop up or out. Is there some tests that I can do or a way to repair the most sandy areas.This problem is mostly at the wall’s edge and at the edges of three step downs that are 8″ in height. Thanks
Hey John,
If you can suck it out with a shop-vac it’s not stable enough. I would take the vac hose to those areas and see how much comes out, then fill them with thinset and fresh deck mud. The deck mud on the edges of the steps WILL NOT LAST – deck mud needs to be contained. You need a mud edge on the steps. These are metal trims normally used for mud countertops which attached to the substrate and filled with wet mud on the vertical edge. It solidifies the edge.
Hi Roger,
I have a couple question here. Last week you answered a question (very well I might add, thank you) I had on hairline cracks in my shower pan. Unfortunately I filled those cracks with thinset, to only find them return the next day after standing in the shower to tile the walls/ceiling. Additionally the base was made with a mortar(Mapei Ultraflex), not the deck mud recipe above. There doesn’t seem to be any movement but the cracks are relentless.
Although the shower pan was just installed, I’m considering redoing it based on the items below that were overlooked. Do you think this can be worked with or should be redone?
1. Pea gravel was not used at the drain weep holes of this 3’x4′ shower.
2. Pre-slope was neglected. Membrane was installed on top of level wood subfloor and around curb. Also membrane corners were not cut but were tucked and folded.
3. Cement board around curb was installed with several cement screws on the side and top of curb. This secured the cement board to the 2x’s but also went through the membrane. If this is the wrong way to attach the cement board to the curb, how would one do so without puncturing the membrane the wraps over it?
4. Lastly after the cement board seam tape over there corners on the shower curb dried, I notice that there are a few air pockets under the hardened tape. Most areas are quite solid and firm, however wondering if this should be ripped out since there is some movement.
I tiled the walls and ceiling but have left a foot above the pan, just in case a demo was needed, hoping this tile work can be left alone if possible. Portions of the concrete board may have to be removed to get all of the pan out, but I’m guessing that would be ok as long as I can do so without damaging the plastic liner stapled to the studs.
It seems like quite the mess, horrible at times, but your sarcasm, lighthearted, and detailed writings really put things in perspective for me. Thank you.
-Zack
Hey Zack,
The first one tells me that it needs to be redone – number two guarantees it. I’m going to email you a link to download a pdf, read through that and it answers all of your questions. It’ll be there in just a minute.
Hey Roger,
Very helpful site- thank you for your time and tips. I have a question about the preslope mud and the final layer of mud- are they the same mixtures? Thank You!
P. Walsh
Hey Pat,
Yup, same mix. 4:1 to 6:1 sand to cement.
Thanks for the quick reply, Roger! Your site is a big help to a DIY’r like myself! I now have you bookmarked.
-Pat
Roger,
Here’s my question. I have a step down shower that I am starting from scratch on a remodel. Code says that I do not need a membrane. Can I put the mud deck directly on the concrete, then tile right on top of this??? Or do I need some type of liner or membrane??
You need a membrane. I don’t know where you are or what code you are speaking of, but without a membrane your shower floor will not be waterproof. The water may soak into the concrete beneath the shower (I’m assuming that’s the reason) but it will lead to problems, it’s just a matter of how much time passes before the problems start to show. Where are you located?
I’m in Florida. From what it looks like, I need to slope my base with with a new deck mud. Then maybe use the Schluter drain with adapter, then maybe redguard or durarock membrane. Sound good???? thank you so much
Yup, that’ll work just fine. You can also utilize the ‘divot’ method. It’s toward the end of this page: Divot method in shower tile installation. That’ll be cheaper than the kerdi drain.
Sorry, one more question. I have durock up, wall seams filled with thinset, and the floor done. I’m putting in a pre-fab corner bench seat. I plan on redguarding the walls and floor. Should I install the bench first before doing any redguard? Or should I install bench, do all seams, then redguard the whole thing????? Thanks for everything! BTW, divot method worked well!
Do the redgard first. When you install the bench just squirt silicone into the holes you drill before you install the screws – that will seal them up.
HEY! Can you send me pictures of your divot? I always use the kerdi drain and don’t have any photos of it. I’d love to write a post describing how to do it and use your photos? Would you do that? You can upload them right to my site here: FloorElf photo upload page I’d really appreciate it.
Just wanted to make sure you received the divot method pics, i sent them a few days ago. Thanks for all your help,
Peace out
I did get them Raleigh, thank you very much. It will help a lot once I get off my ass and actually write something.
Roger, I appreciate what you and the elves are doing here. What tools are you using (or recommend) for installing mud decks? I am leveling/flattening a poorly poured 10’x10′ concrete floor. While I am making vast improvements using your dry mud info, I still have not achieved FLAT! I am wondering if its my technique or my 4″x12″ finishing trowel that needs to be improved. I assume the some dips can be made up with thinset, but I’d like to avoid that as much as I can. I marked a level line along the 4 sides of the room, and using a 6′ level everywhere else for reference.
Hey George,
You need to get yourself a very long straight-edge, called a screed. I have nearly every length up to and including 12′. A six-footer should be fine. You want to create two rows of deck mud about six inches wide every six feet (given a six foot screed) all the way down the room. This six foot apart measurement should be center to center so when you run your screed down these two rows with each end resting on one you have three inches of the ends resting on each – knowwhatImean?
So after creating these two rows of mud, level with one another and every other one you will have essentially stripes of mud at the correct height for your finished floor. Let that set up a bit and start dumping mud between them. Pound it down to just above your lines then take your screed and run it down your runners working it back and forth to screed off the mud to a level finish.
It’s a laborious process, but that’s how you get a glass-flat floor. Been done like that for (literally) hundreds of years.
Roger,
First timer here…
Great write up…I was looking specifically for how much sand to add to Quikretes “Sand & Topping Mix” for deck mud and I wanted to confirm 20lbs of sand to each 60lb bag od “Sand & Topping Mix”…Correct?…Is the Quikrete Sand at HD suitable?
I’m laying a 6 x 5 shower I promised to get done by Christmas. I’m using the Quick Pitch sticks for the pre-slope and mud beds….Any advice?…
Thanks!
Danny
Hey Danny,
I use the quickrete all the time – it’s convenient. i add 1/2 bag (25lbs.) of sand to each bag of quickrete sand and topping mix (60lbs.) This give you a 4.8:1 ratio, it’s a very good mix. Only use the quick pitch sticks for the preslope. Once you get that slope your top slope will be a uniform thickness. If you use them on both slopes you’ll end up with 1/2″ / foot slope.
I am wondering if it is ok to build up my shower floor 5inchs with deck mud? Is that too deep? Do I need any reinforcements in the deck mud or do I just pound it to death?
Hey Clint,
You can build up the floor 5″ with deck mud but you want to install a layer of metal lath halfway through it. 2 1/2″ mud, lath, 2 1/2″ mud. This will give the bed the strength it needs. And pound it to death.
I have a very sandy shower floor I have read it is ok to put a thin layer of thinset to correct this will the tile still be ok or will they pop over time ? I have read my mix may have been to dry should I rip it up and start over
It will be fine – it will not pop over time unless your floor is EXTREMELY sandy. I mean if you poke a screwdriver into it you encounter almost no resistance. That means it was way too dry or wasn’t packed tightly enough.
I read your comment on a dry/sandy mud bed where the guy was peeling up sand when placing his thin set. I have a feeling i’m going to run into the same situation but where he was installing kerdi i’m ready to lay my tile. Can I mix thinset really soupy first like you suggested to him? And is the sandy top going to be fine under my tile? Seems like it is but I want to make sure? I’ve never done this before but my preslope (4-5 to 1 mix no additives) didnt seem as sandy as my top bed (which I think may have been a little less dry.
somewhere else suggested I stuff brush out what I can and use RedGaurd. But that doesnt seem so much a filler as a water proof membrane. You really seem to know your stuff so i’m asking you instead. Any help would be greatly appreciated. Thanks.
*stiff brush then RedGaurd …. stupid phones
Hey Adam,
It may simply not have been pounded down as hard as your pre-slope – were you tired?
You can mix up some thin thinset and skim coat over the top of it to lock in all the loose sand particles. Try to brush off a little bit, but don’t go overboard and start digging ditches in it. Do not use the redgard, the skim coat will work just fine. And yes, the sandy bed will be fine under your tile. Did you know that’s actually how they did it in ancient Rome? It’ll last, really. 
Awesome . . . that is exactly what I wanted to hear. It’s just the last section right by the curb that is bad. I’m thinking I overworked that area trying to get it perfect because it pulled a lot of the water to the surface and I’m thinking maybe that’s why. Gotta be something besides me being tired – because I was tired of the bathroom before I did the pre-slope :p
Thanks
Hoping you can help. My shower floor was improperly sloped and sealed and now water has seeped under tiles and they are all coming up. Water actually sits at one end of the shower stall unless I squeegee it to the drain. I would like to redo the shower floor myself, but I need to know if I can add more “mud” on top of the current floor once I pull up all the tiles. I am very familiar with laying tiles, grouting and sealing.
Hi Janice,
Yes, you can add more deck mud on top of deck mud. You’ll need to use thinset to ensure it adheres to the existing bed, but it will be fine.
So, if I am understanding the process correctly, I take up my old tiles, add a layer of thinset where I want to build up the mud and then put more mud on top until I get the depth I need for a proper slope? Let this all dry and then I can carry on with tiling?
Yes, that’s correct. It will allow the new mud to adhere properly to the existing without creating a weak spot.
Hello Roger,
I just read through a couple of posts about making a shower pan. I am undertaking one myself, and was just getting ready to try to mix up my “mud” for the pre slope.
My question; I was going to use Quikrete-Pro Finish, type S, Blended Mason Mix (with no sand etc). They also have me using the Commercial Grade Quikrete Concrete Acrylic Fortifier. Am I way off track? In your “how to make deck mud” article, you reference one way that is OK (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.) What is the difference between Mason Mix and Mortar Mix? To do a pre-slope for a pan that is 34″ square ( 1/2″ slope to a “center drain” ) about how much do I have to mix if I do the “60# / 30#” recipe?
I am very anxious to hear your reply….I am glad I checked, and found your “blog”!
Thanks in Advance.
Regards, Bob Bond
Hey Bob,
You don’t want any fortifier in there at all. The preslope will be fine with the mason mix and even the fortifier, but the top slope needs to allow water to run through the bed – that’s why it is merely cement and sand. I don’t use the mortar mix for anything, what you want is either straight type s cement and sand or the sand and topping mix (which is only type s cement and sand) and additional sand. I believe the mortar mix has lime in it which makes it sticky, but I’m not positive, I don’t use it for anything. Each bag of S&T and sand will do approximately 6 square feet for your preslope.
Hello Roger,
My problem is SAND. Sharp sand, mortar sand, play sand, the list is long. ORCO makes a product called “Deck Mud”, just add water. Mentioned is ASTM C144, apparently a standard for “Mortar Sand”. Everyone I have spoken with has a name for the sand to be used but hasn’t heard of ASTM C144 nor is the sand so standardized. It seems to me that a sand that is not round, ie “sharp sand” would cement better. However, the packaged sand I find at Home Depot or Lowes varies from very fine round grains in “Play Sand” to coarse sand containing small garvel in “Builders Sand”. Is there a packaged sand you can recommend? Should it meet ASTM C144? Your help is appreciated. Thank you.
Hey Art,
Any masonry sand should meed the ASTM C144 specs. I believe the Quickrete brand sand sold at HD does – that’s the one I use anyway. It’s fairly large and sharp which does work much better for deck mud than normal play sand or round sand. The pre-mixed stuff is pretty good, although I’ve never used that particular brand. It’s not necessarily imperative that it does meet ASTM C144 since that describes aggregates to be used in an exposed mix. In other words, a mix which, when cured, will be the final finished surface product. Deck mud is gonna be covered up with tile so it won’t see the same traffic and abrasion aspects. The larger and sharper the sand the better, though.
Roger,
I am putting a shower in the basement. The slab has been saw cut and removed to hook up the drain to the existing line. The slab is 8″ thick (to my surprise) and there is about the same amount of compacted base. I left 2″ around the edge of the cutout to the face of the finished wall. What I want to do is recess the slab and put in a removable teak wood slatted floor so it is flush with the concrete floor and I want to leave the concrete below unfinished (no tile). Do I install vapor barrier under the first layer of concrete like it was and then put in a liner and then finish with the sloped floor. I am going to use the concrete bricks you suggested for a curb. How can I finish the curb so it looks like concrete. Also, can I use the deck mud to slope from the wall to the edge of the cutout on the 2″ edge I mentioned above, and if so, would I use a liner under it and behind the concrete board? I want the curb, sloped edge and the shower floor to all be exposed concrete so I didn’t want to run a liner over the curb or up the side of the cutout. . I was wondering about a product called Patchcrete for the 2″ sloped area. Any help would be much appreciated! Nancy
Hi Nancy,
Yes. The vapor barrier is for moisture rising up through the concrete – the liner is for water coming down from the shower. You will, however, need the liner beneath the entire shower floor. Just plain concrete isn’t going to work. The best thing to do, I think, is place your liner down there (The patchcrete will work fine for backfilling that hole) then install a sloped floor with deck mud. Once that’s cured coat the deck mud with concrete. The liner will also need to go over the curb. Just use wire lath over the liner on the curb and use it to anchor a layer of concrete over that. You still need to treat the base of the shower as if it will be a tiles surface – waterproof-wise. Concrete is not waterproof.
Hello Roger,
I am building a Roman Tub on a concrete floor. It is approximately 5′ X 32″ and a 2″ drain is next to and in the middle of one of the long sides. I leveled the old concrete floor with Level Quick and chaulked between the Level Quick and the wood / Durarock tub structure. I mixed 1 part portland cement with 4 parts sand and enough water to allow for a “snowball” to be formed. I used wood guides sloped at 1/4″ per foot to guide the mud packing; the highest point is 3/4″ sloping to 1/8″ at the drain; the wood being removed after the slope was established and filled with dry pack. I intend to “paint” Redguard first as a 1 part Redguard / 5 parts water primer and two coats of 100% Redguard.
Here’s the problem: I didn’t cover the Level Quick with thinset prior to “the mud packing”; I did pound the “mud” into place and it stayed together but could be broken apart; I made a ball of the mudpack which after 24 hour curing broke apart when dropped about a foot; the surface of the mud pack is sandy and feels as if I could scratch it away; when I poured water onto the surface to check the slope, the water disappered into the mudpack. I don’t feel confident that this “dry pack” is properly installed. Your comments will be appreciated. Thank you.
Hey Art,
From what you are describing your dry pack is properly mixed and installed. The problem is that you should use wet mud with a roman tub construction – not dry pack. Any vertical walls or substrates should be created with wet mud. Deck mud is supposed to be porous, it’s working properly. And you do need to thinset the base to the concrete (or level quick). It may be fine provided you get enough coats of redgard on it, but I really wouldn’t want to chance it. Deck mud can be scratched, it is not intended for vertical stability (meaning it may not hold together well enough to take the stresses of vertical sheer). I simply don’t know.
Roger,
My first attempt at a preslope was mixed too dry; it just crumbled when I tried to smooth out some high spots. The second attempt went a lot better, but as I was beating the mud to a level line, I had a small amount of water come to the top. I know too much moisture can cause shrinkage, so should I just give it a few days to dry out before installing the pan liner?
Thanks!
Ed
It will shrink as much as it’s going to by the next day, so you can install your liner then.
Hey Roger,
Thanks for the quick response! I really enjoy your site and since you states somewhere that you welcome comments and questions, I have something that just popped into my head. We all know the pre-slope is there to direct the water that reaches the shower pan liner to the drain. And when forming your curb, the top should be sloped to allow water runoff as well. But shouldn’t the 2X4’s (or brick) beneath the shower pan line be sloped as well, to prevent water from running out of the shower? i know it’s just the engineer in me needing to know every little detail, but that’s how it goes.
Thanks!
Ed
Hey Ed,
Yes, whatever substrate is beneath the liner on the curb should be angled slightly toward the interior of the shower.
I had a structural engineer out to my 76yr old house. My mudfloors are cracking on one floor and crumbling and sinking on another. He basicially said live with it , it wont cave in. And to just force grout into the linear cracks in bathroon floor when I reset the loose tile. Im waiting to get the written report to see if he will even mention the floors. Im afraid for my familys safety, and I just talked to a neighbor who is a contractor. He said, I need to remove and replace with plywood subflooring. I thought structural engineers knew everything about structures, that why them cost so much. He said my house had drift, because of the extremely hot and dry summer.It caused alot of wood in area homes to dry out.All my floors warp and have gotten saggy. Any idea what up? Or what to do? Thanks Michaele
Hi Michaele,
If the floor is sagging it doesn’t sound very structurally stable to me – but I’m not an engineer – I’m a physicist.
Sagging is never good, whether it will not cave in or not. I would likely get a second opinion on that, I don’t know that much about complete mud structures as they relate to the sole substrate nor about ‘drift’ – don’t believe we have either around here. None that I’ve seen anyway. Why don’t you go to the forum at John Bridge’s site here and start a thread names something like ‘engineering question’. There’s a guy hanging around there named Bob who will likely at least be able to give you some basic information one way or the other. Sorry I couldn’t be more help but I don’t wanna give you erroneous information and make things worse.
Know what you know, but more importantly know what you don’t! My father always told me that – he was right (as usual)
Roger,
I’ve laid my mud bed and I’m very happy w/ the slope to the drain. I’m using the Kerdi membrane system but the bed is pretty dry. When I try to use thinset over the top to put down the membrane it drags the mud bed up like dry sand. Is this normal and I’m worrying to much or should I dampen top of bed first?
thanks Jeff
Hey Jeff,
It’s normal – really.
You can mix up some thinset really runny and skim over it (pressing hard to fill the voids between the sand granules) then after that cures you can just install as normal. That will lock in all that loose sand and give you a stable bed to set the kerdi over. Dampening the bed first may help but you’ll likely still be pulling sand.
Hi Roger,
Thanks for your quick response on my previous question.
Just like you said, the Rapid Set mortar mix concrete had cracked the second day!! Good thing my dog didn’t burst into flames!! LOL. So like you said, I tore all that out, made me some 5:1 sand to Portland deck mud and by almost 3AM on Sunday night I finished what I thought would be a great pre-slope. Only when I’m looking at it now, there isn’t much of a slope around the perimeter- it’s really leveled!
What I should have done instead was to grab couple of cold ones, and done the pre-slope the next day when I wasn’t so damn tired! But I did pack that mud in real good using a 2 x 6 and a hammer!
So my question is: How can I “add” some slope on the existing mud bed? Can I put some thinset on top and then create the slope using more 5:1 sand to Portland deck mud?
Hey Artman,
You could use more deck mud with thinset, but why do you wanna? The perimeter should be leveled against the walls and slope down from there to the drain. It sounds correct but perhaps I’m not understanding. If you need more slope somewhere you can put down a little thinset and add more deck mud.
Thought I’d chime in again since my project is nearing completion. I went with the the Quickrete 60 lb bag of sand topping mix to which I added 1/2 of a 50lb bag (25 lbs) of Quickrete Play Sand (all from Loewes). And it worked GREAT – and this is from someone whose exposure to masonry work was limited to pouirng cement for posts up til now.. This stuff is easy to work with, keep it dry – it WILL set up SOLID and it works better dry than even a little wet (voice of experience there).
and thanks again, Roger, it is strong enough to drive a truck across (well almost)
Hey Kami,
Weird, isn’t it?
Properly mixed deck mud is very cool stuff. Just for the record depending on compaction (how hard you beat the crap out of it) the cured deck mud after 28 days has a 2000-2200 psi – so you can drive a truck over it if you want. 
Thanks for the update.
i used sand mix for my deck mud is this ok? also like i read in your post i can scratch it with my finger. i don’t know if the tile thinset will stick to it. any help would be great. thanks
Hey Bob,
If you used straight sand and topping mix then it should be replaced. Sand and topping mix is pre-mixed at 3:1 sand to cement. Deck mud for your shower should be mixed at 5:1 to 7:1 ratio. The extra sand will compensate for movement and stresses without transferring them up through your tile installation. If there isn’t enough sand in it the stresses may cause it to crack. Thinset will stick to it just fine, though.