Unbonded pre pitch... forgot to use thinset before applying deck mud to concrete slab

[Dp22]

I'm breaking tools around here. Tamp it down!! Quit lollygagging around!!!

[Davy]

Crap, I've been using the wrong mud for 45 years.

David, gluing the liner to the outside of the curb is fine.

[cx]

I think the problem there, Davy, is the Quikrete guy was talking about Deck Mud, while you're talking about deck mud.

[Dp22]

I'm trying to install the pan liner and I've run into some problem areas. My original intention is to still have the liner run above the monument bench I plan to build. The result is a fold that is nearly the entire width of the bench itself. I didn't think it would be the big at all. I guess I can move the plywood in the back corner in more to accomodate another fold and squeeze it in there?

My other question is where the liner meets the curb. I never really found any solid instructions on how to fold the liner at the curb. To me, whenever there is a 90 degree angle I think there has to be a fold / crease to have it change direction.

After finding a youtube video on it I decided to do a few practice strips. I first made a cut kind of scoring the liner along the inside curb edge to lap it over the curb on the wall. What's left is me making a small crease due to the curb itself and lapping the liner over the top of the curb to the outside edge.

Like they did on this video at 14:50..
https://www.youtube.com/watch?v=cUkny-fIuWc

That's a good way to do it? I can put Oatey's glue and the corner dams on the appropriate corners and inside the corners but my main goal is that everything is well built and waterproof.

Should I glue a small 4" x 8" pvc flashing attached to the wall and curb first for extra waterproofing?

Just another gray area I guess.

Thanks.

[Davy]

I build my seats the same way but the liner behind the seat is a separate piece. Having it in one piece is even better but you have to deal with the long folds. I glue the overlap.
A 4x8 flashing piece is fine, just try to get everything as flat and tight as you can.

[Dp22]

Wow. That's a great idea covering the bench area with just another glued sheet.

Excellent. Thanks for the advice!

[Dp22]

I just finished the top mud bed. How you pros mix 5 bags of deck mud and lay it out in 45 minutes is beyond me. The majority of it took 1 hour and then I had to remove the 1 x 4 guide boards and filled it in as fast I could.

I'm wanting for the top bed to wet dry? By having a sheet of plastic over it for 2-3 days and giving it some water with a mister every 5 hours or so is fine?

I chose to set the top bed first and do the curb second. How long do you wait for doing the curb? Mortar S is adequate? From the tutorial, the thinset is placed right on top of the Mortar S for the curb. No scratching or etching in the curb mortar is needed?

What is the ideal height you leave for the drain? I scraped around the perimeter to barely get 1/2". I'm just curious what others shoot for?

I hope everyone is having a great day.

[cx]

Don't mean to rain on your parade, David, but what you really wanted for that top mortar bed is a consistent thickness of at least 1 1/2 inches with a perimeter that is completely level. The even thickness will follow your pre-slope, which was (we hope) a minimum of 1/4" per foot slope from the farthest corner from the drain. I see some potential problems with that floor draining properly and with the appearance of the wall tiles at the floor junctions.

Not sure I understand the curb questions, but yes, a Type S mortar will do for making the curb and no, there is no need for any scratching of the curb surface prior to setting the tiles. Am I close?

My opinion; worth price charged.

[Dp22]

Oh man. That's not the news I wanted to hear.

When I measured for the top bed I made a cohesive layer of 1.5" thick and added the 1/4" per slope in addition to that. Something I just didn't need to do I guess.

At the far back near the bench the bed is 3" tall. At the other side it is 2 1/8" tall centering and sloping towards the drain.

I'm in trouble, as building the bed up to match the 3 inches would be too aggressive of a slope to hit the drain with the tile.

The other option maybe is to start seeing if I can shave some of the bed off and try to take it down to 2 1/8. But it's been drying for 6 hours now.

The pre slope under the liner is 1/4" per foot. So everything should drain fine.

What's a possible fix that I can use?

Dangit..

[Dp22]

With the bench I have almost a perfectly square shower. The bench will be roughly have a 20" depth. I haven't decided yet. Nor do I know what height to make it either. But, with the bench the shower is mostly square.

The slope meets at the midpoint of the drain. The difference from the front of the shower to the midpoint mark of the drain is 1/4".

Is it possible to make up that space with a bonding agent with more mortar or maybe a self leveler?

Man.

[cx]

Well, clearly it's not what you want to hear, David, but my recommendation would be that you remove that top mortar bed, call it practice, and do another after you have built your bench.

My opinion; worth price charged.

[Dp22]

Maybe I'll just rely on a good quality thinset to make up the space. I have worst case scenario is 5/8" difference from the bench to the drain. I think more like 1/2".

What is your opinion on tiling the floor first and using a good quality thinset to make it level around the edge?

Thank you.

[cx]

I think you'll likely find that to rank somewhere between one of the most difficult tile experiences you've ever given yourself and impossible. But I been wrong before.

Not to mention that with half an inch or more of thinset mortar you'll be seriously degrading the design of that receptor. Those traditional receptors are designed such that water can easily penetrate that top mortar bed and drain down while evaporating up. That's the whole purpose of the dry-pack type of mortar.

But it's all entirely up to you, David. You can do whatever you think will work best in your individual application. I can only tell you what the industry guidelines call for and what found to work over the years. Others may disagree with what I'm recommending.

My opinion; worth price charged.

[Dp22]

O.k..

Well, I want the shower to function well. So if it means redoing it then.. oh well.

It seems like a thinset remover/ grinder wheel would make short work of dropping the level down to 1 7/8" though.

Thanks!

[Dp22]

Well, I tweaked an old achilles injury laying the top bed last friday. So, I contacted a tile company to finish the job. He stated because I used CBU he wouldn't touch the shower. Stating the grout will crack for whatever reason and the water will wick up the wall. He preferred the hot mop and floated walls with mortar method.

With that I contacted tech support for the cbu and the topic was water migration in and up the cbu. His recommendation was placing the cbu on or 1/8" above the pvc liner and redguarding the entire shower pan. Essentially sealing the wonderboard and pvc liner together without disturbing the weep holes. After the redguard is applied (x2) and dried continue with the top bed sloped 1/4" / foot to drain.

At this stage, coat the shower pan and walls with a final layer of redguard or similar product and leave a 1" perimeter around the drain so all the water can slope to the drain, penetrate the top bed and drain thru the weep holes.

Lay tile afterwards.

What is your opinion on this?

Thanks.
David