How thick should a pre-slope be over a Concrete foundation [Archive] - Ceramic Tile Advice Forums - John Bridge Ceramic Tile


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07-23-2019, 08:41 PM
I was hit last fall by hurricane Michael. I have been rebuilding my house for months and am to the shower now. We had to remove the old shower, which had a rather large molded corian shower pan. I couldnt get it out, so I finally got the crow bar and pryed it out, snapping the 2" PVC drain pipe. I am needing to repair that first, then make the floor have a 1/4" p/ft drop down to drain. How thick should this pre-slope be? Can it be like 1/8 of an inch at the thinnest point, or should thick should it be exactly at the thinnest spot (Drain)?

Next I will have to water proof it, and was planning on using rubber sheets, folded and stapled to wall. I have since seen some paint on stuff (Redguard) as well as some orange sheet material, that is taped at seams. Since this is my first time, should I venture to something like that, or stick with the rubber sheets folded method?

Once the waterproofing is in, how thick should the shower pan be at the thinnest section?

I need to know this, so I know how high to set my drain, which should be set before I can pour the pre-slope or shower pan, correct?

To make things more difficult, my shower has a built in seat, so I will have to waterproof up, then turn back horizontal, then up wall some more, to waterproof in seat.

As for the pre-slope and pan, is there a specific mortar mix I should use, or stay away from? I see some mortar that costs around $8 for 50 lbs, then others that is $20 for 10 lbs. Why the huge difference, is there something Im missing right here?

Thanks in advance, it is greatly apprecaited!!!

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07-23-2019, 09:59 PM
Welcome, Paul. :)

You've gotta decide first what kind of water containment system you want to use before you can even decide what kind of drain you want to install.

You can build a traditional receptor with a mud pre-slope, then a PVC or CPE liner (not rubber), for which you'd want a standard three piece clamping drain. But if you intend to keep that wood-framed bench, I'd recommend against that.

You could use a direct bonded waterproofing membrane system. The orange one you mentioned is sold by Schluter Systems and is called the Kerdi Shower System ( My preference is for a gray one sold by USG and is called the Durock Shower System ( With the Kerdi system you can use gypsum drywall as your backing material if done per the manufacturer's instructions, but with the Durock system you need to use CBU.

With either of those systems you need to use a bonding flange drain that is part of the system and you make a single mud floor, properly sloped to the drain. Over that you apply more of the same waterproofing membrane. You'll need to do a little research on both, but we've helped many hundreds of visitors build such showers.

The deck mud you want for the sloped floor of any type receptor you build will be a very simple mix of sand and Portland cement mixed in a ratio of five to one with a little water added. You can find much information on that in the Shower Construction section of our Liberry.

Decide what type of shower waterproofing you want to use and we can deal with your specific questions at that point.

My opinion; worth price charged.

07-24-2019, 08:31 AM
My preference would be to use one of the sheet applied waterproofing methods. When done properly, the entire shower, from the pan all the way up the walls, is waterproof. In a conventional shower, the waterproof liner on the pan only goes up a few inches above the curb height...the rest is typically water resistant. Now, gravity plays a big part in that...the water always will end up down on the floor and the small amount that gets into the walls tends to evaporate. There should be a moisture barrier behind it to protect the studs, but it is not technically waterproofing.

The sheet applied waterproofing is sort of like putting up wallpaper except you're using thinset as the glue. There's more to it, but it's not usually as daunting as you might expect.

07-26-2019, 04:20 PM
I had to bustout my old drain, and now have a hole in the middle of foundation. I am about to replumb it, but first have to determine how thick I want the pre-slope at the drain? This should be the thinnest spot of concrete (Sand/Portland Cement) mixed at a 4:1. Is there a specific thickness I am looking for in my pre-slope?

07-26-2019, 04:31 PM
I am about to make a pan on my first shower, and have a concrete foundation, and the drain was busted out. So I chipped away some concrete foundation to get to drain pipe. I need to know how high to plumb the drain. Specifically, how high do I want my pre-slope to be (How thick) where the pre-slope meets the drain?

1.5 - inch?

thanks in advance

07-26-2019, 05:15 PM
Paul, please don't start new threads with the same questions as it results in confusion and duplication of effort on the part of our all-volunteer army of helpers. If you don't feel your getting a timely response, make another post to bump your thread to the top of the queue for attention.

There is no requirement for any part of an actual pre-slope in the ceramic tile industry because the pre-slope in a traditionally built shower receptor is part of the plumbing and their requirements don't address your thickness question. That's why I asked what type of receptor you're planning to build.

My personal minimum for any deck mud application, regardless the type of drain or the type of waterproofing, is 3/4ths of an inch and that might well apply to your application. But that doesn't really tell you how high to plumb the drain as we don't really know what type of drain you intend to use, eh?

My opinion; worth price charged.

07-26-2019, 06:25 PM
Good point. Here is my plan....

- Fix the busted drain pipe, plumb in a new drain.
- Fill the busted conceret hole with a mixture of 4:1 Sand mix:Portland Cement. - Then use that mix to fill the hole as well as make a pre-slope.
- I will then use pvc mat, to make a pan liner, that will drain to a 3 peice drain.
- I will cement board the walls, fill joints with non modified mortar and some 6" fiberglass mat.
- Then I will redgard along the corners and edges, apply a waterproof tape into wet redgard, then smooth with troxel. Then do 2 complete coats of Redgard from the ceiling to the shower pan.
- Pour a shower pan, with 1/4" drop per foot for both shower pan and pre-slope.

Is this the right way to do this?

Thanks again!

07-26-2019, 06:57 PM
I'd set the bottom flange part of the drain 1/2 to 3/4 inch off the slab surface. Use concrete mix to fill in just to the top of the slab. I also like to paint on thinset to the edge of the slab to help the concrete bond. Rebar can also be drilled into the edges of the slab if you want to.

Then use a thinset slurry on the concrete to bond the dry pack preslope up to the bottom flange. I'd go 5 to 1 with the dry pack.

I'd also notch the studs so the pan liner will set back a little from the face of the studs.

07-26-2019, 08:00 PM
4. For finishing the CBU you want to use a 2" alkali resistant fiberglass mesh tape. You can use an un-modified thinset mortar to fill the joints, but there is no reason not to use a modified mortar if that's what you'll have on hand to set your tiles.

5. Not sure what you might mean by "waterproof tape" there, but Custom makes a fiberglass mesh they recommend for use with RedGard in that application and that's what I'd recommend you use.

6. By the time you get to installing the wallboard you should already have installed your pre-slope of a minimum of 1/4" per foot from the drain to the farthest corner of the shower. The final mud bed over that liner should be of a consistent thickness of a minimum of 1 1/2 inches, following the slope of your waterproof liner and capturing the bottom of your CBU wallboard.

My opinion; worth price charged.

07-26-2019, 10:26 PM
how you suggest I do the bench, if I dont concrete board the top and footboard. I plan to add a slight pitch to the top.

07-26-2019, 10:50 PM
With that kind of water containment system, you could build a bench with block and mortar inside the liner. No need to waterproof it, which is an advantage.

You could also install a Better Bench (, just add some blocking before installing cement board to secure the bench. You would cover it with Redgard at the same time as your walls, but since it's filled with deck mud, you'll have to wait three days to waterproof it. If you're not pressed for time, it's a good option, since it doesn't take up any floor space.

07-27-2019, 02:15 AM
What Kevin said, I add more pan liner on the studs in the area that's behind the seat and along the sides draping it over the floor pan liner that goes up the walls. Then build the seat inside that using concrete blocks and mud. It works well and is probably the cheapest way to build a seat.

I wouldn't have a problem using the Better Bench, it also makes a very good seat.

07-27-2019, 06:54 PM
I understand that you need to have a pre-slope with 1/4" rise per ft, then put the shower pan on top. lets say you are building a square shower, and the drain is in middle, there should be even height across the corners, what happens when you have an oblong shower, and the drain is offset? How do you maintain the correct slope, and also a level height around the edges? Should I just lay the pre-slope according to the 1/4" rule, then when I do the Shower pan, I make sure the edges are level then?

In my picture above, to top right corner, is 48" so it should be 1" above the drain. From drain to the bottom side of shower, is only 16", so it should be like 5/16 above shower drain. There is no way to keep the heights level. Im thinking make level when I install shower pan, but dont want to do it until I am positive.

Thanks for the help!

07-27-2019, 08:14 PM
Paul, please keep all your project questions on one thread so folks can see what you're working on and what's been previously asked and answered. A moderator can give it a more generic title any time you'd like to suggest one.

See Post #9.

The required slope is a minimum requirement. You would make your perimeter of the pre-slope (again we're assuming you intend to build a traditional shower receptor) level all the way around at the level of the maximum height. In your case that would be a minimum of 1" higher than the top of the bottom portion of your clamping drain. A bit higher is better to be sure you meet the minimum requirement. The slope will be different in the other quadrants of your receptor because of the drain location.

I would recommend as your first step that you center the drain in the shower footprint.

My opinion; worth price charged.

07-28-2019, 12:04 AM
Thank CX. I will keep all post regarding my shower in this thread. Sorry about that. Thanks for the replies. I am going to get rolling on this tomorrow. Since my drain is 3/8" above foundation, I will just go to top of floor plate, approx 1.5". That will make it easy for me to drag the sand mix anyways.

07-28-2019, 05:52 AM
Make sure your bottom plate is level all the way around. It might/probably won't be

07-28-2019, 07:42 AM
You ever gonna tell us how you plan to create the receptor and waterproof the shower, Paul, or are we just gonna keep guessing what you might be planning to do. We help more efficiently when we know what we're helping with. :)

07-28-2019, 09:32 AM
Post 7 says pan liner and Redgard on the walls, Kelly. :tup1:

Like Shawn and Cx mentioned, you want the perimeter of the shower floor to be level starting with 1 inch of preslope mud at the 48 inch corner. The other areas will be steeper than 1/4 inch per ft.

07-28-2019, 10:23 AM
Thanks, Davy. I know we kept talking about a pre-slope, but I was never sure. Guess I missed that post #7. Seems I'm doing that more and more lately. You must be getting old. :D

07-28-2019, 03:31 PM
I do that all the time. The one post I miss has all the info in it. :)

07-28-2019, 06:11 PM
Pre-slope is done. Got a good slope of 1" fall from all sides, the long was 48" and needed all 1", the rest have a more pronounced slope. I will make up difference in the shower pan I pour next. What y'all guys think for my first concrete job ever, unless you count setting fence posts.

07-28-2019, 08:01 PM
Paul said,"I will make up difference in the shower pan I pour next." Not sure what you mean by that but the top mud bed should have the same pitch as the preslope. You'll want the top mud bed level around the perimeter, just like the preslope. So, the areas where the drain is closer to the walls, the steeper the pitch will be.

The mud looks good from here. :)

07-28-2019, 08:42 PM
Paul, the top mud bed must be a uniform thickness of a minimum of 1 1/2 inches, following the slope of your pre-slope.

If that mud felt like concrete, it was too wet. Doesn't matter much on the pre-slope, but it's very important that the top mud bed be done correctly so it is sufficiently porous to function properly. Deck mud is not concrete, nor does it want to be. It wants to be deck mud. It will be happy as deck mud.

My opinion; worth price charged.

07-29-2019, 12:45 AM
Ok, so here is a new one. I have the pre-slope done, and am wishing I had put in a kerdi drain. Which some experience with fiberglass, I feel that the Kerdi system would be right up my alley. Either way, I have a 3 peice drain, so its to late to switch to kerdi, or is it? Convince me that it is a bad isea to try that now, using Kerdi with a traditional PVC line type 3 peice drain. Anybody done this and make it work?

Ive also noticed my wall area way out oy alignmenbt, so I am going to have to do some shimming and shaving.

Agagin, original plab was to use REDGARD and PVC mat liner. Thanks for the help everyone. I am about to head out of town for a few days, going to take the moment to roder some more supplies. If I make this switch, I need to do it now. Thanks again!

07-29-2019, 06:51 AM
If you wanna switch to a direct bonded waterproofing membrane system you would simply remove the pre-slope you just made (deck mud is dirt cheap, DIY labor is free), call it practice, chip out enough concrete to change to a bonding flange drain, make a new mud bed with the proper slope and continue with your shower.

I would recommend the USG Durock Shower System membrane and drain if you elect to do that. Better membrane, easier to work with.

My opinion; worth price charged.

07-29-2019, 09:02 AM
There's also this option (, if you want to keep what you have without all the demolition.

08-01-2019, 04:58 PM
i just spoke with tech sup[port for Redgard. The rep told me that I could:

1. Install pre-slope
2. Install Cement backer board
3. Fill CBD joints with mesh tape and Modified thinset
4. Redgard from the ceiling all the way down the walls, to the drain,
5. Add in the shower pan mud.

He said if I did this, I wouldnt need any pvc liner, nor waterproofing system. Is this correct? I am hesitant to do this until I hear from some of you all thats its ok. I believe this would be the easiest option for me and my skillset, but it would be worthless if it wont work and leaks.

08-01-2019, 05:12 PM
It's his product, Paul, he gets to tell you how to install it.

I personally would not use a liquid-applied direct bonded membrane to construct a shower receptor, but it is done. You want to be very, very careful in the installation of the product in that application. It is not like painting the bedroom walls, 'specially the portion that is to make up your shower receptor.

My opinion; worth price charged.

08-01-2019, 07:45 PM
CX, that is exactly what I was thinking. i think I am going to take back the Redgard and Oatey PVC liner, and get some of the durock membrane and the Kerdi drain adapter.

Will the Kerdi drain adapter work with the durock membrane?

The Kerdi dkrain adapter is abs, will that work with an Oatey PVC 3 peice?

When splicing joints, the durock method sells a 5" strip to overlap with. Can you just take the regular membrane, and cut into 5" strips, instead of buying the mini 5" strip rolls? Is this the same material?

I have a bench, and am just not confortable with trying to waterproof it with redgard and pvc liner. I am not in a hurry, and want to do this right, and it looks like the durock/kerdi membrane is the way to go now.

08-01-2019, 07:54 PM
The Kerdi Adapter Drain is mechanically connected to the bottom portion of a clamping ring drain and it matters not at all whether you have PVC or ABS.

That said, I would still vote to chip out enough concrete to install a bonding flange drain, either the USG or the Schluter, correctly to the drain riser without the added height of the adapter.

Yes, the USG Durock Shower Membrane will bond to a Kerdi drain just fine, but neither manufacturer will stand behind the installation. You don't care about the warranty, though, because any failure you might have will be an installer error.

My opinion; worth price charged.

08-02-2019, 06:31 PM
Pic 1 - Shower Entrance

I am confused on what to do with the Concrete board in the blue highlighted area. I plan to put the durock cement board on the red areas. but should I span it across the blue area also. If I dont, it wont be no where near level. If I do, how to I nail it down, as I wont be able to nail it without putting hole into liner. FYI, I am going with the PVC liner before pouring slope.:smash:

08-02-2019, 06:33 PM
Original Picture

08-02-2019, 08:40 PM
If you're gonna use the USG or Schluter system then the Durock would be covered with membrane, wouldn't it? Maybe you've changed again.

08-02-2019, 08:46 PM
Yeah, Davy, post #31 says he changed again. :) FYI, I am going with the PVC liner before pouring slope.

Paul, there is no acceptable method of using CBU to create the curb in a traditional shower receptor. If you'll visit our Liberry and find the Shower Construction thread you'll see a good article by John Bridge on how to construct such curbs using expanded metal lath and "fat mud." You gotta do that.

The Noble Company makes a foam cap that might be the only acceptable alternative I've ever run across, but I've never actually used one.

My opinion; worth price charged.

08-02-2019, 09:08 PM
CX, I assume you are talking about building it out like the picture below. If so, I think I am out. I dont think I can do that and make it hold. I think I need to order some durock and a kerdi adapter drain. The deeper I get into this, the more I realize your advice was spot on, from the very beginning.

Let me ask you this, Since I already mage pre-slope, if I go with your original advice, and chip away the drain, and put in a traditional style kerdi drain, I wouldnt need to make a shower pan on top of the pre-slope, would I? I mean, my pre-slope looks great on the level, and you can tile right over durock membrane, so why would I need a second slope? is this right?

08-05-2019, 07:23 PM
Where do I end the Durock CBU? On the flat wall, there is not a stud behind where the end of the sheetrock is. Should I cut it back to a stud? If so, you can see in the picture the blue tape, that shows where the stud is, I should just overhand the CBU up to that point correct?

As for the other picture, where the durock will meet the sheetrock in a corner, do I want the durock to lay over the sheerock, or the sheetrock to lay over the CBU? Basically, what is the corner made of? CBU or Sheetrock?

While on this subject, what is the best way to end the tile and make a tile/sheetrock connection?


08-05-2019, 07:48 PM
If you're using a surface-applied membrane of some sort, you can end the CBU right against the sheetrock as it is now, since it will all be covered. You will, however, need something to join those two edges together. A strip of 1x4 will work, as long as you have space to fit it in with that foam.

If you're not using a surface-applied membrane, then the CBU needs to go to the outside edge of that half-wall. I'm assuming you're going to have glass centered up on that wall.

Regarding the second picture, if you're not installing tile on the outside of that wall, then you'll want to put a sheetrock corner bead on all outside corners, vertical and horizontal. Use whichever type of corner matches the ones in your house. You can just run the cement board up to where it covers the lumber only. No need to cover the edge of the sheetrock, since the corner bead will be there.

If you are setting tile on that wall outside the shower, then it doesn't matter which is covered, the sheetrock or CBU edge. But you will need to put some mesh tape and mortar there around the corner.

08-05-2019, 07:51 PM
Since I already mage pre-slope, if I go with your original advice, and chip away the drain, and put in a traditional style kerdi drain, I wouldnt need to make a shower pan on top of the pre-slope, would I?

You'll find it impossible to set the drain without full support of the drain flange. For that, you have to force wet mud under the drain after it's set, or set it into wet mud at the time it's attached to the riser.

If you go with a Kerdi drain, you can either bust out the existing mud you have down and build it back up with the new drain, or use the Kerdi drain adapter and build mud on top of what you have.

08-10-2019, 10:07 PM
So I made a final decision on how to waterproof the shower. I went with the PVC liner and will be using redgard. I completed the CBU installation, taped with fibatape, and then thinset the the tape/joints.

Should I apply a light sand tomorrow before starting the redgard? If so, what should I use to sand with? Is there any tips on this? Thanks!

08-11-2019, 09:15 AM
Do I need to gently sand the thinset over the joint tapes before redguard application

08-11-2019, 10:52 AM
Paul, we can't see your taping job from out here and can't tell what you might have on your walls. If you've created an excessive buildup while taping and filling your joints, you may want to smooth them out a bit. If you wanna do that, I'd recommend a rub brick that you can get from your local home center. Look like thissy here:


Or, if you have a regular brick laying about, use that.

My opinion; worth price charged.

Tiger Mountain Tile Inc
08-11-2019, 04:24 PM
In regards to post 36, I've attached two photos that are hopefully helpful.


With this photo, you'll want to make sure there is framing behind where the two wallboards meet. The idea is that the tile will cover both surfaces but the cement board will be in the wet area.


With this photo, you'll want a metal drywall corner on the outside assuming that you want drywall on the non-wet side.

Additionally, there's no reason that you can't do a divot method using Noble's drain flange ( and cement board on the curb. I definitely wouldn't use Redgard for the shower pan but to each his/her own.

08-17-2019, 08:07 PM
I finished the waterproof membrane and poured the shower pan this afternoon. Finished around 3pm. I was going to set the floor pebble/stones in the AM, probably around 7am. I plan to use the Versabond Modified thinset mortar, as shown in pictures. Also was going to use a 1/2" toothed trial, is all this acceptable? Anything I should do different? Any tips or tricks, DO's and DONT's you could give me would be greatly appreciated. Thanks!

08-17-2019, 08:32 PM
I'm gonna guess you mean to use a half-inch square notched trowel to set your small stones, Paul, and I'm gonna caution you not to do that. You'll be spreading far too much mortar for those tiles and will end up with more mortar squeezed out of the joints than you have under the stones. At largest, I'd start with a 1/4" square notch and see how that works. If that's still too much mortar, you may want to switch to a vee-notched trowel or maybe Schluter's Ditra trowel if you can find one of those.

The object is to set the tiles with a minimum of 3/32nds of an inch of mortar under the tile while having a minimum of squeeze out into the joints. The squeeze out is optional, but the minimum 95 percent coverage on each tile is mandatory.

I'd also recommend you get the regular VersaBond mortar and not the LFT version.

My opinion; worth price charged.

08-17-2019, 10:03 PM
CX, I will go get a 1/4" square trowel or a v- notched trowel in the morning. I will also get the other mortar. Can you please give me an example from either a home depot or lowes? I am having a little trouble in picking out what type of mortar to use. I will get exactly what I need, just need to know exactly what to get. Thanks!

08-17-2019, 11:53 PM
The bag you show is Versabond LTF which is for large tiles. You can get regular white Versabond at Home Depot.

08-18-2019, 06:04 AM
Following up to Davy and CX post; I’ve posted a link to the Versabond at HomeDepot.

08-18-2019, 06:26 AM
PC7060. The link you posted doesn't help. It shows all the different versabonds. I need to know which one specific to use. Thanks

08-18-2019, 06:34 AM
C'mon, Paul, that link shows only one VersaBond, in white and in gray.

08-18-2019, 07:11 AM
Not for me, it doesn't. It showing 12 items, including buckets and bags

08-18-2019, 07:53 AM
Ohh boy, I might have bigger problems. My sand mix bed has some loose aggregate at the surface. I mean it's rock hard for the most part, but there is a few spots where, if I run my hand over it, small grains of sand dislodge, not chunks, but small grains. Can I thinset over this, and stick the floor, or did I screw this up royally.

08-18-2019, 08:04 AM
Look at the link again, Paul. You'll see only two bags that say just VersaBond on'em. One white, one gray. You won't see that name on any of the other buckets or bags. Don't know how PC coulda been any more helpful.

You might wanna vacuum the top of your mud bed, but I think it's likely you could simply set your tiles on what you've got.

08-18-2019, 08:10 AM
Thanks CX. I kinda felt goofy when I realized that there was only 2 bags with versabonds on it. I went and bought a bag of the regular, not LFT. Now, when I do my tile, which is 12x24, I need the LFT, correct?

08-18-2019, 09:43 AM
Yes, you'll be able to use the LTF on the 12x24 tiles.

08-18-2019, 10:32 AM
Dry pack (deck mud) is purposely made poor (very little cement) and dry so it'll be porous. That way it will absorb any water that gets thru the floor tiles. Water flows easily thru dry pack mud and allows the water to make it's way to the weep holes in the drain. I usually slick my dry pack down with a trowel after I get it in place which gives it a harder crust on top. Like Cx said, you can run a vacuum over it if you want and if it still wants to erode a little, you can skim coat the floor with thinset. It won't ever be as hard as your driveway, a little gritty on the surface is normal. :tup1:

08-18-2019, 05:58 PM
Well my first try and tiling a river rock floor went over like a fart in church.

I did my shower pan with sakrete sand mix, called sakrete and they said it was a premix 4:1 sand :Portland. I mixed the snot out of it while adding water. Maybe I didn't add enough, but made snowballs, then when I thumbs them, they would break, rub my hands together, and it wouldn't leave smears.

Did pan yesterday, due to unforseen circumstances, it took me about 25 hours from finishing pan until I started smearing thinset. Used the versatile thinset, not the LFT, but regular fortified, white bag.

When I started buttering the pan, thinset wouldn't stick, and rolled and collected loose sand. Pulled out small chunks of pan. On part of pan, it did good, but other parts it pulled up small chunks, approx 1/4 to 3/8 deep of the pan. I realized something wasn't right, (not like what I saw on YouTube, and aborted. Used scrapper to get what I had spread up. Threw it back in bucket. After done, bucket looks like cookies and cream ice cream

How bad did I screw up? Can I just thinset the to with non modified, soupy mix, or should I just bring the house down?

08-18-2019, 06:01 PM
Pictures of a monkey screwing a football bat

08-18-2019, 06:03 PM
More pictures

08-18-2019, 06:18 PM
If the mud is 4 to 1 then it has plenty of cement in it. It might have been a little too dry or maybe not packed well enough. Again, slicking it down with a flat trowel after you placed it would have helped. If the sand is rolling up when you spread the thinset then you may have to redo the mudbed.

08-18-2019, 06:35 PM
It's just in a few spots, and those spots, it's maybe 3/8" deep then it's hard as a rock. I think I didn't get it wet enough. I packed the snot outta it.

08-18-2019, 07:12 PM
Okay, try patching it, hopefully it works. Any loose stuff needs to be picked up before patching it.

08-18-2019, 10:09 PM
Dave / CX, lets say yoiu were in my situation, and was going to try and salvage it. What woudl you do? I plan to get a dish scrubbing brush and remove all aggrigate that is loose. Then sweep it up, Throw it away. I am gong to have a few holes to patch, what woudl you use to patch? Im thinking either thinset, non mondified, or sandmix, and double the portland. That made a damn good slurry that I think would bond and hold.

Any trade secret you want to share Thanks!

08-18-2019, 11:41 PM
Don't use a scrub brush. With moderate force you'd be able to wear away at even well-placed and well-packed deck mud.

Use a shop vac to get anything that's loose, whatever stays down is placed well enough. Then you can probably get away with using a modified thinset if it's just a few small areas 3/8" deep. Anything larger or deeper and I'd use a cement-based patching compound. Don't use sandmix for shallow areas, it won't hold long-term.

08-19-2019, 05:33 AM
What Lou said. I would do the vac test. Usually if it holds up to the vac then it's strong enough to stay down. If the vac continues to pull it up, replace the mud.

08-22-2019, 01:28 PM
So I did the vac test, and it vac a little bit up, then got hard. I did have some gaps or holes in pan though, not all the way to liner, but some maybe 1/2 deep. I mixed up some thinset, and filled the gaps. Then sanded smooth and sloped. I put some water to it, and it drained well,. I clogged the top hole, and flooded, and it seemed to soak it through the thinset, hit the sand mix below and drain out weep holes. Probably took a little longer than expected because it didn't penetrate the thinset near as fast as the sand mix (almost instantly). Pan is sloped and solid now. Question is, I still have to thinset the pan, to stick river stones. Is there a point where there is just to thick of thinset to make it function correctly? As some spots will have over 1/2" thick thinset. Other spots will just be a slim coat.

I think what caused my problem is I packed and leveled the edge all the way around, and by the time I got to filling it, some of the edge was to dry to stick to? It appears everywhere some of the sand mix broke apart is where the pan filler meet the original pan packing edge. Since I am sloped and solid, can I stick rock floor to it? Is there a time window, where I can stick thinset to thinset? Is there a Max thickness I can have on thinset?

08-22-2019, 05:20 PM
We try to avoid deep holes and thinset over 1/4 inch but there are no rules. I don't think the few deep holes filled with thinset will hurt anything. I assume you're still using the same stones you show in post 58. I would spread a little thinset with the proper notched trowel and stick the stones down. Thinset will stick to thinset, just spread and set a small area at a time.

09-29-2019, 05:42 PM
I just grouted a river rock shower floor using Prism oyster grey grout. It looked good, then about 20 mins after sponging, everything is turning a really like, white color. If I sponge with damp, it looks good until dry, the. Back to the blurry white look. What do I do? It's been about an hour.

09-29-2019, 05:47 PM
Working on picture.

09-29-2019, 06:37 PM
Scratch the surface when it's dry and see if the proper color is beneath the white.

09-29-2019, 07:06 PM
How would I scratch it?

09-29-2019, 07:11 PM
With a hard, semi-sharp tool, Paul. Screwdriver or similar.

09-30-2019, 10:00 PM
I guess it was just some grout haze. I wiped it down good with wet sponge, adn then buffed with microfiber, adn it looks fine. However, I have another issue, the river rocks come with some black plastic mesh that is glued to bottom of rocks. I really thought I trimmed that mesh back good, but I guess I didnt. So in 4 stops, I have a 1/8" peice of that black mesh plastic sticking out, just looks liek a single bristle. So can I chip out grout there, cut them off, tehn when I grout walls, just add a little grout to those area? Basically, will a newly mixed batch of grout stick to the old grout? If so, how deep should I chip it out, just enough to cover, or should I go deeper so I have more surface area to stick new grout to?

10-01-2019, 07:29 PM
How is the best way to make edges on the outer wall edges? In the pictures you will see where I have 2x Half walls, with a entrance in the middle. I plan to tile up the half walls and maybe 3" out on the outside of walls (not shower side). So when going up those walls, which is 4.5" wide, how to I form edges? Do I have to line the outer edges with bullnose, and cut them evenly down middle to make for this 4.5" wide area, and butt them together, because I never seen 4.5" wide tiles that are bullnosed on two sides? Should I line it all with Rondec? Any other suggestions?

10-01-2019, 08:01 PM
One way is to back-bevel or back/miter the edges to wrap around those corners, Paul. Like this:


Get a look like this (sorry, best photo I've got):


10-01-2019, 08:19 PM
I like the Rondec.

It’s not inexpensive by any means, but, for me I figured I’m in it this far; what’s a bit more. Comes in different colors and finishes. It’s taken a few good hits with stuff and is holding up very well.

10-02-2019, 05:55 AM
Getting accurate miters in tiles demands a stable saw, a good blade, and the framing needs to be darn straight/plumb.

Jeff's Rondec will be way more forgiving, and it looks good. You could also consider using stone/solid surface material to "cap" all that. The caps are wider than the walls/curb are and you'd just tile up to the edge of the caps. IMO, a solid piece on the curb is preferable to tile; no grout lines means no chance for water getting into the grout and causing mold/mildew.

10-02-2019, 06:53 AM
I should have mentioned that I will be topping the seat, 1/2 walls and curb with granite.

10-02-2019, 07:34 AM
When I did the river rock floor, some of the black plastic mesh is sticking up through the grout, like 3 little bristles. I am kind of a perfectionist, Soni want them out. I was thinking of chipping a small section of the grout out and cutting the plastic mesh out, the when I grout walls, just touch up the areas. Question is, will the grout stick to grout, maintain color, and strength? I used CBP Prism, which is 2 bags to a box, only used 1 bag, so should have very similar match

10-02-2019, 06:15 PM
Take a razor knife and try to cut the mesh down below the grout surface. Dig a small hole with the knife so the new grout will have enough depth to grab hold. It should match real close but can't promise it to.

10-02-2019, 06:24 PM
Thanks Davy!

Have another question, I am trying to cut some tiles with a 45° edge. The bottom of tile, which is the 145° angle, looks perfect. The 45° angle cut looks busted up and chipped. Why is this? Is this because of blade? saw? Technique? I tried fast, tried slow, cutting with tile to right, tile to left, taped, upside down, fast, slow, same results. the 45° cut just doesnt have anthing underneath tosupport it, while the 145° does and looks perfect. I am using a Diamondback brand diamond 10" blade, almost new, cut 11 rips through the river rock sheets, thats it. Should I try a different blade? Suggestions?

10-02-2019, 07:19 PM
Look at the top photo in post #74, Paul. Are you leaving some "meat" on that top edge as in the photo, or are you cutting a sharp edge there?

What kind of tile are you cutting? Are they glazed tiles?

10-02-2019, 10:19 PM
The tiles are glazed. Natural color throughout, with a thin layer of the Calacatta Peitra color on top. I tried cutting on factory edge leaving a littel meat, and it worked fine. However, now I have another prediciment, when I do straight cut (no miter, 0° cuts) I am getting slight chipping of the glaze top coating. I bought a diamond balde from harbor freight, Diamondback brand. Could I get better results with a better blade?Should I get a sharpening stone? Any brand recomendations on blade or honing stone? Thanks!

10-04-2019, 05:35 PM
So if I am doing straight down cuts, no miter, and am getting little chip out, what is causing that? Is it a dull blade, cheap blade? Saw not stable enough? What blade would you recommend for a 10" saw, and cutting porcelain which is glazed?

10-04-2019, 05:48 PM
I've never used Harbor Freight blades so I can't say. I like Pearl brand porcelain blades from Daltile but there are other good blades.

10-12-2019, 06:56 AM
When I put the PVC liner in, and had to make a corner fold, the CBU didn't lay perfectly square vertically. When I laid my tiles into corner, the gap, spacing between tiles is perfect at 3/16, however, at the bottom, the gap is maybe 1/16 wide. The tiles are set, and I have tiles above already. I was wondering if I took a diamond Dremel cut off wheel, could I widen the gap, or will I just meaa the tile up?

I should have cut the tile say 24" at top tapered to 23 7/8 at bottom. Should I just bust it out, then cut a correctly shaped tile to compensate for the gap and reset it?

How hard will it be to bust out tile, remove the thinset, versatile LFG modified, with durock and 6 coats of redguard? This is the bottom tile, so I don't want to punch hole into redguard, even though in theory, the PVC liner is behind?

When I set another row yesterday, I took some 2x8 and drilled them together to make a 90, then set some scrap tile to make an identical gap, was going to try and Dremel that first to see if possible before dremeling on the set shower tile.

Should I just leave it alone?

FYI, this is where the bench starts, so the grout line will only be about 16" high, the it will meet where the granite seat overhang will be, so this isn't like my true corner of shower. Most everyone will probably not see it, but I am kind of a perfectionist, and I have already seen it, so Everytime I shower, which will be everyday, I will see it and be like "Dang, I screwed the shower up". Also of note, the wife hasn't noticed it, and say it looks great currently. If I don't point it out to her, she probably will not notice until she cleans after complete.

Another thing I thought of, was getting a diamond grout removal tool, and basically running it into corner up and down, the sand away the tile, then grout. I could always just caulk that corner, and let the caulk like look like grout line, I have color matching caulk, matches the grout color, CBP oyster grey caulk and oyster grey Prism grout.

Thank you in advance for the advice, and thank you to everyone who has contributed to thread so far. I appreciate it.

10-12-2019, 09:27 AM
The ship has sailed for the only proper fix for that problem, Paul. You should have notched your wall studs and set your blocking such that you could accommodate the thickness of your liner folds at those corners. You'll find a description and drawings in the Shower Construction thread in our Liberry.

Without knowing just what kind of tiles you have and seeing the extent of your problem (photos), I couldn't really say how successful you might be in trying to widen the grout lines at the bottom of your corners.

Whatever else you do, the correct treatment for those joints is to fill them with a flexible sealant. The recommendation would be a color-matched 100 percent silicone caulk, which can be found in satin or sanded texture these days to match most any grout.

My opinion; worth price charged.

10-13-2019, 06:01 AM
Thanks CX. I did notch the walls for the other corners, I got 5 of 6 done, just slipped my mind I reckon on that one. I think I am going to have to either live with it, or bust it out, and cut a miter into that side to accommodate. I am leaning towards busting it out, since I have twice the material needed, and it will bother the hell out of me forever if I don't. I repaired my whole house after this storm, and I see the small things I said screw it, Everytime I walk through that room. No one else really does, but I do. I am slowly, but surely fixing them 1 at a time.

10-13-2019, 06:04 AM
CX, speaking of color match caulk, where all should I caulk instead of grout? If I have 4 walled shower, I assume each of the corner joints, plus inside niche? Maybe anywhere I go from rock/tile to hard surface (either granite or quartz) haven't made that decision yet. Is there a standard practice for where all to caulk over grout? I reckon if I caulk that bad tile corner, I wouldn't have to worry about grout line there then?

10-13-2019, 06:13 AM
Thanks CX. I did notch the walls for the other corners, I got 5 of 6 done, just slipped my mind I reckon on that one. I think I am going to have to either live with it, or bust it out, and cut a miter into that side to accommodate. I am leaning towards busting it out, since I have twice the material needed, and it will bother the hell out of me forever if I don't. I repaired my whole house after this storm, and I see the small things I said screw it, Everytime I walk through that room that has a small error, I notice it. No one else really does, but I do. I am slowly, but surely fixing them 1 at a time.

10-13-2019, 09:33 AM
The ceramic tile industry calls for the use of a flexible sealant in the tile installation every place there is a change in plane of the backing material or where the tile installation abuts a dissimilar material. Only exception I'm aware of is at the drain in a shower floor where grouting is permitted.

But some folks grout a lot of places in a shower that call for the flexible sealant. And some of those joints crack. In a properly constructed shower that's only an aesthetic consideration, but it's still a crack and still a tile installation failure. Entirely up to you how you wanna treat yours.

My opinion; worth price charged.

10-14-2019, 07:39 PM
CX, so how would you build one for yourself? Where all would you caulk?

10-14-2019, 08:43 PM
Are you familiar with the Fifth Ammendment to the United States Constitution, Paul? :D

10-14-2019, 09:37 PM
Silicone your corners, use a profiling tool (I use these with great results or blue tape to get a consistent line and you should be able to hide that pesky inconsistency in your corner and silicone the change of planes

10-15-2019, 06:19 AM
I siliconed all my wall to wall and wall to floor junctions, and where my corner benches abut the tile walls, Paul, and used the tape method to get clean straight lines with minimal clean up.

I have a niche placed low in a 40" high by 27" long wall. Technically a lot of plane changes but I grouted the whole thing.

10-16-2019, 08:06 PM
Trying to cut some calacatta marble chair rail in mitered 45° cuts. This is going over like a fart in church. I get half way through cut, and it just crumbles. any advice?

10-22-2019, 01:12 PM
How would you prep this outside corner, where the shower tile meets the sheetrock? If I lay a flat peice of wood on the sheetrock, you can see the small gap between the CBU and sheetrock, where corner should be. Should I just use a sheetorck metal corner? I thought I recall that you cant use certain metals near the thinset as the alkaline in the crete will mess up the metal? Any help is greatly aspprecated. Thanks in advance, to everyone!

10-22-2019, 08:06 PM
I'd tape and thinset that corner square and run a row of tile up the outside wall. Looks like you already plan to run tile on the outside under the pony wall.

10-23-2019, 01:37 PM
I planned to when I started the shower. Unfortunately, I cannot find any bullnose to match the tile. It is calacatta gold or Pietra, and the only companies I can find that make that tile in bullnose, the color of the bullnose is few shades of white off from the tile. The better half said no way, it clashes to much. I found some Calacatta marble, that matches closes enough, in Chair rail. However, I can only get it to cut straight without chipping. If I try to cut at 45º, the marble just crumbles. (I think it is cheap marble). I tried different blades, also. If you have any advice on cutting that marble, then please let me know.

So I was going to either use some schluter edging like Rondec, quadtec, etc Or do the Marble chair rail straight up the sides, but cannot make that 45º turn at the pony wall. I am laying 3cm Granite across the two tops of pony wall, and across threshold, so I could tie the straight cut marble chair rail into it. On the side with the funny corner, I could make granite pony wall top, run past corner and curve into wall, then run the chair rail straight off of that, similar to the way you trim a window/window seal.

Basically, have the granite cut like a stool, and have chair rail placed on that outside wall like the casing in image below. Thoughts?

10-23-2019, 04:40 PM
With the tops of the pony wall(s) capped with granite, and then the CR set just below that, you're still going to need to cut some tricky returns for the CR. The stool and apron in that photo both have returns.

12-02-2019, 04:37 PM
I had my granite cut and ready to install. Question is, how do I install, do I thinset it in, or do I use silicone caulk? For the pony wall caps, I don't think it really matters, but for the niche and bench seat, I am confused here. My initial thought was to set the niche granite, silicone the edges, then build over that, thinking it would keep water from getting under the granite. However, if I do this, a water gets in there anyways, will this not cause the water to be trapped between the granite and redguard? Same goes for Ben h seat. It I caulk around granite on 3 sides, this should create a barrier to prevent water from seeping in, however, water gonna do what water does, and will probably eventually find its way under there. If it does, surely I want to drain it, right? I mean, would it get stagnant, smelly, and mildew/mold? Would I be better to just thinset it, then grout around, to allow the water to easily move through there if needed.

12-02-2019, 08:20 PM
Paul, I would set those pieces of granite the same as any large piece of ceramic tile. Get as close to 100 percent thinset mortar coverage on the back of the piece as possible. Treat the joints the same as you would the joints around any other tile you set.

My opinion; worth price charged.

12-04-2019, 12:22 PM
I am having major problems with cutting some marble chair rail. I purchased at Lowe's. This stuff is super soft, and the edges just crumble. I have tried sharpening blade, went out and bought best blade from warehouse, I tried cutting dry, wet, tried a cut off wheel, a Dremel, I even tried freezing the darn things, which I must add, worked the best so far. I tried pushing through blade, pulling into backside blade, flipped them over, etc.. I am really at wits end here. I tiles the shower for these specific trim pieces, and am going to have to bust tile out and start over if I cannot get this figured out.

Using primarily a 10" wet saw with brand new blade. Best cut so far was on a frozen piece that way laid flat on a tile, pushed against fence, pushed through backside and pulled through frontside, then sanded with 400 grit. I have probably wasted about 15 pieces so far. Also, I can get it to cut perfect if a straight 90 cut, but when putting a 45 on it, the narrow corner just crumbles. I am wanting to picture frame a window with these, so I have to have 8 corner 45 cuts.

I have tried the, find some different material, didn't work. Went to about 10 different stores, couldn't find a match. Order samples from 5 different online store, didn't match. They don't make bullnose for my tile, so I am kind of S.O.L. if I don't figure this out.

Maybe a water jet? Is there some kind of trick I am missing? I even thought of freezing them in ice, then cutting the whole block and let water heat up and drop off? Maybe pour an epoxy over them until cut? HVLP them with a polycrylic? Anything is greatly appreciated. This is for the only person that matters, the wife, so I can't let this get the best of me. Got to figure out a way forward. Thanks in advance.

12-04-2019, 03:45 PM
what make and model saw are you using? what make and model blade are you using?

12-04-2019, 04:29 PM
How 'bout a photo of what you're trying to cut, Paul.

12-04-2019, 07:28 PM
This is the chair rail.

As for the saw, Its a chicago electric 2.5hp, and I have a Diamax Cyclone 10". The saw isnt the best brand, but it seems to cut porcelean tiles just gravy.

12-04-2019, 08:41 PM
Lowe's site isn't very helpful with the photos. Not even the same trim in each of their views of the product.

Not familiar with that saw or blade. Perhaps others will be. My first guess would be that you have some wobble or out-of-round or deformed mounting hole or similar causing some vibration. Similar vibrations could also be present using your hand-held tools. Just guessing, of course.

Not sure I understand "the edges just crumble." I've certainly had difficulties cutting various kinds of tile and stone, but don't recall anything that would fit that description.

12-05-2019, 08:16 PM
The trim is solid, but once you cut it, it crumbles like a sandcastle. Like there is no bonding agent to hold it together, once the polished skin is pierced. Ether way, I'm over it, I'm just going to use the white Rondec and move on. I am wasting to much time with this. Haven't been able to use shower since Oct 2018.

So here is my next question, where exactly would I want to run the tile to in relation to the granite top? I had planned to use this trim, which accounted for some wall space, but don't have it now, and my tiles won't fit. I don't really want a bunch of short tiles right along outside edge.

Friend who does this, said I should run it all the way to the edge of granite, but I am thinking of stopping it short, so my tiles work out.

Is there a specific place I am looking to end in relation to granite? How much tile needs to be out past the frameless glass?

My other option is to carry it all the way out, but seam exactly where glass is going, so the glass and silicone kinda of hides the seam.

In pictures below, the green laser line is centerline of the granite which is placed evenly on the pony wall. The tile right on top of granite can be cut down, or used as is. The top tile is my full length tile. Can I just put the Rondec up from that, then build remaining walls off the Rondec back to corner? Is that enough tile sticking out past the green laser where the seamless glass is going?

12-05-2019, 08:20 PM
Flipped pics

12-05-2019, 08:32 PM
I would usually take it out to the edge of the granite but you may have to hold it back. You already have to lower half of the shower tiled so there's no turning back. You can see the importance in measuring to see how the cuts will fall. You'll know that on your next shower.

Edit; Looking at your last picture. I would have started with full and half tiles against the metal trim and put the cuts in the corner.

12-06-2019, 09:17 AM
Thanks CX. Yeah, I did the tiles so they lined up with shower valve, and split distance between outside wall and pony wall, and didn't take into account the tiles would extend past the pony wall. Ended up 1.5" to short with full tile. Ugh!

Anyways, I think I can fix it, where I still use full tiles, and hide the grout line. I can cut the full tile on green line, then use the glass to over the grout line. I could even make there not be a grout line, like use no spacer, and push them flush. Will there be a problem with drilling that close to the end of tile though?

12-06-2019, 06:46 PM
This would be a problem with every other row. Is your glass going up high enough to hide the problem near the top?

12-06-2019, 11:29 PM
Umm, probably not. Good thinking. You guys are the best.

12-09-2019, 12:13 AM
How high does traditional frameless glass go? Is there a standard? Say 80" Thanks!

12-09-2019, 07:09 AM
There mightbe a "standard" height, Paul, but I've never seen it. There is a practical height, though, and that's right around the height of the shower head arm.

12-09-2019, 08:13 AM
I say to the ceiling as long as you have 8 foot ceilings. Looks nicer.

12-10-2019, 05:16 PM
Ohh boy, I done really up and done it now. Had some extra thinset so I set the granite threshold, and forgot to out any drain angle to it. It just looks water. Not good for a frameless shower door. Any ideas on how to remove without completely screwing up granite nor the redguard liner? Lol, this is beyond stupid mistake.

12-10-2019, 06:34 PM
Put a level on it. What's it showing? Was the curb level before the stone or did it have slope into the shower?

12-10-2019, 11:12 PM
It's perfectly flush. Glass guy said I needed a slope, so it would drain into shower. I got it up, used a plunge saw to slide cut thinset.

12-11-2019, 08:11 AM
I would for SURE re-apply the redgard all over the curb. No way it remained intact with the sawing action. Also, the curb should have had a slope on it BEFORE the slab of stone is attached. I guess sloping the stone is better than nothing though.

A tip...make sure the glass guy does not drill ALL THE WAY through the stone when he sets the glass. Tell him to cut the fasteners and only drill like 3/4ths through the stone. This will ensure your redgard stays intact. I have been pushed back on this many times but I insist. They will want to just shoot silicone into the hole.

12-13-2019, 03:00 PM
Thanks Mike, good advice.

12-13-2019, 03:02 PM
When you are setting to Dec to a outside corner, is there a trick to anticipate the added depth of the thinset? I'm using 3/8 inch thick tiles and have the correct Rondec for the corner, just trying to make sure it lines up perfectly.

12-13-2019, 04:06 PM
It's usually somewhere between 1/8 - 1/4" thick, depending on the size of notch your trowel has.

12-19-2019, 02:48 PM
How would you finish this outside corner where the tile is going to meet sheetrock. This is the one in the left side of picture. I am fine with how to do it on right side. I have 3 options, but would be open to another if you have better suggestion. Please keep in mind, I do not have bullnose tile to finish with, so it looks like I am going to have to use Rondec profile for corner. Also, I have granite slaps for the tops of both pony walls, they just are not installed yet. Will be using frameless glass setup. In the pictures, the blue is rondec and the greeen would be tile grout lines, although they are not evenly spaced, you get the idea.

Option A, Carry tile all the way out shower, and down external wall, take it to the far left, until it hits the closet door trim. Once above close door, run rondec to ceiling, and tile to rondec. Also, although not illustrated in picture, I would tile the right outer wall, to cabinet, then above granite vanity top.

Option 2, tile outside walls, but stop at top of pony wall where it meets granite top. On bare sheetrock, run a strip of rondec across the top of last time, approx bellybutton height.

Option 3, use rondec to finish the framing of shower entrance, and carry it straight down, I woudl only tile underneath the shower entrance granite slab, to the tile floor below the cardboard.

Again, any other advice is apprecaited, this is my first shower, and I hope, the last. I stole way more bricks than I want to swim the river with again!!!

12-19-2019, 06:56 PM
I usually take it around the corner like in Option A.

12-19-2019, 08:26 PM
Davy, would you run it all the way to ceiling? Or stop short? Would you run it all the way to the Door frame, then rondec above?

12-19-2019, 08:35 PM
Since your tile walls go to the ceiling, I'd take it to the ceiling too.

If you're tiling to the door frame at the bottom (from the towel bar down) then I'd do it all the same.

12-19-2019, 11:30 PM
Davy, you said "If you're tiling to the door frame at the bottom (from the towel bar down) then I'd do it all the same."

Does this mean, that you would tile that whole wall, like floor to ceiling, and shower to door frame, then above door, go all the way to end of wall?

12-20-2019, 07:06 AM
Does this mean, that you would tile that whole wall, like floor to ceiling, and shower to door frame, then above door, go all the way to end of wall?
I don't know about Davy, but that's how I'd do it - tile above the closet door too. IMO, having the tile die against the door casing is a natural place to end it, but carrying that line above the casing the tile doesn't have a natural termination point, and the trim will simply look like an extension of the tile. It would look the same done that way even if you had a BN.

To avoid more trim I'd have also capped the vertical ends of the knee walls with the same stone you're using for the tops, but I think that ship has already sailed.

12-20-2019, 06:20 PM
I was talking about tiling it just like Option A shows but the whole wall can be done, there are no rules, both ways will work.

12-21-2019, 01:23 PM
SS3964spd and Davy, Thank you both. Your advice, has done something I never believed could happen before, like move a mountain monumental. You convinced my wife, that I was right! :wohoo:

I now have full approval from Mrs. Doubles D's to carry tile on outside wall. So here is the next question, can I just scratch up that wall really good, then, thinset and set tile to it, or do I need to install CBU? All the sheetrock I pulled out previously, was Greenboard. I dont know if that is just ordinary sheetrock, or greenboard on that outside wall. Its been painted a few times also. I do have one of those heavy duty sanding pads on a stick for sanding sheetrock mud. So I could scratch it up pretty good, and put some deep scars in it for the thinset to hold. Maybe reinforce it with some of the screws I used for the concrete board? What about mastic?

12-21-2019, 01:45 PM
Glad we could be so convincing, Paul, though to stay out of harms way we'll only refer to Mrs. Paul as, well, Mrs. Paul. :D

So long as the paint on that wall is well adhered (not peeling) I'd just scuff it well with, say, 60-80 grit and tile right on it. And since you likely have thinset mortar on hand I'd....wait for it...stick with that.

12-21-2019, 03:22 PM
yeah, I have some Versabond LFT for large tile that Im using. I reckon I will STICK with that then. Seriously though, thank you for the help. It is appreciated.

As for the Mrs. Paul comment, I forgot this shows my real name, on most forums, my name is Double Dees... Of course, Lucy is my Lab Retirever.

I went ahead and ripped the paint off, as it kind of just peeled off anyways, It wasnt adhered too well. I have the sheetrock ripped down to the Cardboard outter layer. Should I put a layer of primer on it, or just versabond LFT it to the cardboard lining?

Also, where the new tile (Calacutta) meets the existing bathroom floor tile, how would you transition this? Should I just leave a 1/4 gap, then grout it when I grout rest? Should I use some type of schluder? or another type formed over the shelf item?

12-21-2019, 03:52 PM
If the paint did peel off, I'd take great care in ensuring it's all off. If it is, and you're down to the drywall's paper face, I'd be inclined to put a coat of primer on it so that the paper doesn't draw the moisture out of the mortar resulting in a possibly weak bond.

My older brother has two boxers, Lucy and Ethel. A pretty funny pair.

12-21-2019, 05:04 PM
I'd use the Mapei Eco Prim grip. Lowes should have it.
Here you go.

12-21-2019, 05:59 PM
Could I use my leftover Redgard instead of buying a primer. I have a whole gallon of redgard I had to buy, to patch a spot where I punctured the original redgard liner.

12-21-2019, 06:03 PM
Not at all the same sort of product, Paul.

My opinion; worth price charged.

12-21-2019, 08:29 PM
Thinset bonds real well to sheetrock and I can see the Eco Prime improving the bond. I don't know if Redgard would help or not.

12-26-2019, 11:36 PM
Ended up using this stuff to prime sheetrock. Man, the thinset really sticks to it. I couldnt hardly get it to whip off with wet sponge. It goes on and dries a deep blue color.

01-07-2020, 12:38 PM
Getting closer. Just have to grout

01-07-2020, 03:22 PM
Looks good, Paul, I really like how the tile looks wrapping around the corner and around and over the closet door.

01-10-2020, 01:58 PM
Thanks Dan.

01-10-2020, 02:03 PM
I had to bust a few tiles out today, at the top of the knee wall, because they were cut to short. Once I went to set the 2nd knee wall granite top piece, there was to much of gap between top of tiles and bottom of granite. It would have bugged me out. Anyways, I figured that this would be a good time to see how well I did with getting full coverage with the thinset. What you guys think? I see a few missing spots, but I'm not sure that didn't break off when I hammered it out. It took a few swings and bounces to actually get the tile to crack. It would take a pretty substantial blow to actually crack one if you were not trying to.

Houston Remodeler
01-10-2020, 02:33 PM
Coverage looks good to me !

01-12-2020, 10:44 AM
I have a few questions about grout.

I'm doing the grout now. Did 1/2 yesterday. Have a few questions.

1. A few places need touch up, like we wiped out to much grout, and there a sharp edge on tile sticking out past grout line, can I grout on top of grout? It was grouted yesterday.

2. How much lip should there be? Like should the grout and tiles pretty much be flat? Or should the grout be indented?

3. How do you finish the the transition between top row of tile and sheetrock ceiling? Color matching caulk?

01-12-2020, 10:47 AM
1. What grout? Be specific.

2. None, ideally.

3. Generally, yes.

01-12-2020, 07:37 PM
CBP Prism grout. I think this is good stuff, but I really dont like it, as it is super fast setting, and there just isnt any way you going to get a bag out before it sets up, Really, in about 30 mins, what left in a bucket is hard as a rock. I had to get sledge hammer out to get it out of bucket. LOL, this was my favorite bucket...

Thanks CX. You have been a huge help with this project. Really, Thanks everyone!!!

01-12-2020, 07:49 PM
With cementitious grouts you're limited to living with what you've got or removing all of it at least down 2/3rds of the tile thickness and re-grouting. New grout won't bond effectively to old grout.

My opinion; worth price charged.

01-13-2020, 01:18 AM
I use Prism on nearly every job and I've never had it get rock hard in 30 minutes, even in the summer. It will get hard in a couple hours but it's not a problem because I never mix a whole bag at a time. If you're having a problem with it setting faster than you like, mix smaller batches.

01-13-2020, 04:42 PM
That's what I did Davy, broke it down into 2 lb mixes, using the 1lb for 4 ounces water. If I needed any extra water, I would drive from sponge. That worked great. Is the prism you use, the fast setting type? I wonder if I just got an oddball? It even says on box, don't mix more than you can work in 30 mins

01-13-2020, 06:11 PM
I think all Prism is fast setting. I didn't know that for a long time, it acts like any other cement based grout to me although I did notice that it gets hard in a couple hours.

01-15-2020, 08:55 PM
About to caulk the corners with silicone caulk, and am wondering thedifference between these two caulks. I will be caulking inside corners and floor to wall transitions. One caulk has a sanded texture, and looks a lot better, but I am afraid to use it for this situation. Advice on which to use is appreciated. Thank you!


01-15-2020, 09:14 PM
The one with the sanded texture is not a 100 percent silicone sealant and is not really suitable for your application.

The one that is 100 percent silicone I have not used, but suspect it is a glossy finish and I'd not want to use it in my new shower, 'specially if I had sanded grout.

You can go get what you really want, a 100 percent silicone in satin or sanded texture, from the folks at ColorRite ( in colors to match any brand of grout on the market.

My opinion; worth price charged.

01-15-2020, 09:39 PM
thanks CX, that is exactly what I will do. I want the sanded look, and I want to be 100 Silicone, and good mold/mildew resistance.

01-16-2020, 08:33 AM
but suspect it is a glossy finish and I'd not want to use it in my new shower, 'specially if I had sanded grout.

In a complete boneheaded move I made that exact mistake; used a non sanded color matched silicone for the wet areas, and a sanded color matched acrylic in the non wet areas, both were the same color.

The difference is striking, and not in a positive way.

01-20-2020, 08:40 PM
So I ordered the color-sil 100% sanded grout, and then cut out the existing with a razor blade. Question is, exactly how clean should I remove the old stuff? Is there a trick? I have it pretty clean, but every now and then you can see a small spot like a slither inside the cracks.

01-20-2020, 09:47 PM
I can't see what you have from over here, Paul, even when I squint real hard. 'Specially when you don't have a geographic location in your User Profile and I don't even know which direction to look, eh? :)

All I can tell you is your new silly-cone will not stick to your old silly-cone, so you'd like your old silicone to be all gone. Up to you how gone that is.

The purpose of the silicone is to allow for movement accommodation while providing a more aesthetically pleasing joint. The joint you have with nothing at all in it is quite effective, just not too pleasing to the eye, eh? Whatever you do will likely be an improvement, but the cleaner the joint you start with the longer lasting will likely be your re-grouting endeavor.

My opinion; worth price charged.

01-23-2020, 10:59 PM
So Colorite messed up my order, and sent me some high gloss/sanded mixture. The color was good. I thought that this caulk looked greasy, but that wasnt grease, it was gloss. Unfortunately, I am now going to have to cut this crap out again, for 2nd time. I will be reinstalling the original, 100% silicone caulk in color match from Custom Building Products. 1/2 the costs, color matches better, and applies easier, and has less sheen that the Color-Sil.