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Chris A
02-06-2014, 09:10 PM
I hired a general contractor to remove a shower to the studs and slab foundation and build a new porcelain tile shower from scratch.

The original construction was a hot tar shower pan, and when removed it revealed a rough, flat concrete surface. The crew dug-out the old metal drain, connected a new 3-piece drain kit to the plastic p-trap, backfilled the hole, and I assume used the cement product shown below to patch the floor.

So far, so good, I think.

Now, I'm confused by what the work crew is doing for the pre-slope. Instead of using mortar and packing it in like I see in all the online videos, they've troweled on this same cement product in rough fashion and sloped it toward the drain.

I'm worried that the typical mortar mix was not used and that the texture is so rough. I'm also wondering if they intend to use this same product for the setting bed, as I don't see mortar mix in the work area.

Before they started the pre-slope, I showed the lead worker a YouTube video by Sal DeBlasi of demonstrating the creation of a pre-slope using mortar. I thought he understood and said that's what he was going to do, but due to some language issues there may have been some miscommunication.

I've attached three photos showing the cement product used and the condition of the pre-slope.

Thoughts? Concerns? Am I heading toward disaster or are my concerns misplaced?

Thanks in advance for any help.

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Houston Remodeler
02-06-2014, 09:57 PM

Welcome to the forum.

Sorry to hear about your troubles. Sadly, we hear this all too often.

The good news; you are correct, the contractor is not. Here ( is how to mix the mud as shown by ol'd JB hisself.

Have the guys re-do it. If they elect not to, send them home and find someone who knows the proper sand to ceement ratio before they start.

02-06-2014, 11:01 PM
I don't think the product they used, in and of itself, is precluded from being used a pre-slope material. I personally wouldn't use it because it is most likely a lot harder to shape than what we normally use. That much is evident from your picture.
I used fast-drying cement a time or two years ago so that I could do the pre-slope, liner, and cement board in the same day. (I'm not that young or fast any more, so there's no point in using it now.)

The key is whether it's sloped properly at 1/4" per foot minimum, with no dips or humps that will impede drainage. Obviously, you don't want any sharp edges that might poke a hole in the liner. Yours doesn't look like it's properly installed.

Of course, I would NOT recommend this same product for use as the mud bed that sits on top of the liner. I don't think it's going to drain water properly like a sand/portland mix at 5:1 ratio.

02-06-2014, 11:04 PM
Another note: Nothing against non-English speaking tile setters, but if he can't understand what you're saying, how do you expect to get the job done properly? If you can find a good translator, more power to you (and him). I recently used a bricklayer that spoke no English at all, but his 16 year-old son was with him at all times to translate, so we didn't have a problem.

02-06-2014, 11:22 PM
The big deal is that that part must be smooth and properly sloped. Using that material made it much harder to shape, but could be okay. All it has to do is hold up the liner and not poke a hole in it so whatever moisture gets there can drain to the weepholes. No birdbaths or ridges allowed since the liner will mirror the shape of the preslope. What goes on top of it is much more critical.

02-07-2014, 10:52 AM
Welcome, Chris. :)

The pre-slope is not technically part of the tile installation, it's part of the plumbing. As such, the salient questions are, is it solid enough to support your shower floor and is it sloped sufficiently to provide proper drainage.

The final mud bed must be done correctly, though, and I doubt your guy's know how to do that or they would have recognized that method would also have been easier to use for the pre-slope.

And I fully agree with Kevin on the language barrier problem. If I have a subcontractor who wants to leave me with a crew having no English speakers, he's invited to take them all home with him. No matter how simple the task at hand it's not gonna be done correctly without proper communication and that requires a common language. I speak only English, but I also write the checks. That means the official language on my jobsite is English. :)

My opinion; worth price charged.

Chris A
02-07-2014, 12:05 PM
Thank you for the warm welcome and for the helpful replies!

I met with my general contractor this morning and informed him that I was not satisfied with the work and I wanted it removed and redone with a dry pack mortar pre-slope. He tried to tell me that it didn't look too bad and would work fine and maybe it could be smoothed out a bit. I said that the work as done looks nothing like all the examples I've seen online, and that my research tells me that a dry pack mortar pre-slope is the best practice.

I asked, "Do you have anyone on your crew who knows how to do a dry-pack mortar pre-slope?" and he said "No."

I said, "Can you find someone with experience doing a dry-pack mortar pre-slope? If not, I will find one."

So we're both making phone calls at this point trying to find a resource with the right skills. And believe me, when that person shows up, I will be asking lots of detailed questions about the process they will be using to make sure I'm comfortable with their approach.

Not sure I will find someone willing to just get the shower ready for tile without getting the tiling part of the job, too, but we'll see.

Richard Tunison
02-07-2014, 12:14 PM
A couple images to help you out.

02-07-2014, 01:57 PM
Good luck finding someone for that task. A tile shower is generally considered a monolithic installation, in that no part of it can be removed without affecting other parts.

Since there is so much at risk if a shower leaks and causes water damage, and usually the proper fix for such a problem is complete demolition, then most installers don't want just part of a tile shower, they want all of it or none of it.

Reason being, if I do the waterproofing and someone comes behind me and does the tile, then the shower leaks, who do you think I will blame? If you were to have a problem, you could have two different installers standing there pointing their fingers at each other assigning blame.

If it were me, I'd get one guy/company to do the whole thing. :)

02-07-2014, 01:59 PM
I'll change that to one guy/gal/company to do the whole thing.

No offense to the installers of the female persuasion intended. :yo:

Chris A
02-07-2014, 07:27 PM
"If it were me, I'd get one guy/company to do the whole thing."

Thanks for that advice. I will definitely consider it.