It depends. Cement board isn't a substitute for waterproofing. The entire system has to be planned by someone that understands deflection and waterproofing. Your joists may need to be reinforced. It depends on the design.

It's more a question of, when I step out of the shower, does that tile that i step onto need to be also water proofed? or when planning to scrub the tile floor, would it be an issue if I scrub it with a good amount of water?

JIm, yes I have. And the cement board would be covered in water proof stuff. I just wasn't sure if the guy was supposed to also palce it on the floor or just the shower. He only mentioned it the shower part during the proposal. My understanding is that the rest of the floor would be tiled on the plywood.

It’s not always needed on the floor. But something is. An uncoupling membrane can be substituted if the floor meets the proper thickness for support, and also for the joist rating. It has to meet both conditions.

Here is than you ever wanted to know about tile underlayment. https://www.ceramictilefoundation.org/blog/ultimate-guide-to-underlayment-for-tile?hs_amp=true 

“if the floor meets the proper thickness for support”, which is what I wrote above. The joists have to be tall enough, thick enough, and not span too long between support points. Plus, the thickness of the subfloor has to be considered. https://www.johnbridge.com/vbulletin/deflecto.pl 

The women have already covered it.

I am not a pro but in normal use, you don't have to waterproof a bathroom floor where you step out or certainly not because you are washing it. Kitchen tile floors are scrubbed without that kind of waterproofing. What kind of copious amounts of water are normally left on the floor?

I am assuming a shower with a curb because a curbless shower requires an entirely different approach since the whole room is a wet room.

Most people don't leave puddles of water in the bathroom - they step onto bathmats or rugs which absorb the drip. I don't dry off in the shower and my floor might be damp but it doesn't have vast amounts of water even immediately after showering and is actually fairly dry by the time I exit.

My shower floors and walls are completely waterproofed as is my shower curb. My tiled bathroom floor is just tiled with no particular waterproofing just as my tiled walls (non shower) are not tiled with any particular waterproofing.

We need to know if she is asking about curbless. Virtually any shower that is not a tub/shower is "walk in" . I think the term is over used . ....and often applied incorrectly.

Thus......does the shower planned, have a four inch masonry and waterproofed curb, or not. It can still be without a door : )

It depends what's the subfloor wood or cement??? If its on a cement slab no concrete board is needed...

If you just tiled on a wood subfloor the tile will crack fyi.. That's why people use cement board on the floor not because of water proofing cement board isn't waterproofing anything.....

There will be a curb between the shower and floor. I'll read up on the link provided

"ultimate underlayment for tile". Thank you. I think laying the tile directly on the wooden plywood floor just doesn't seem right.

Just know there is absolutely no need for the SAME waterproofing of a bathroom floor, as a shower and base. You do need a proper substrate for tile. You are not flooding the bath. Only the shower. The shower curb must be masonry, it must be waterproofed. and a four inch total height is sufficient. It must have a solid surface/no grout top with a minimal pitch toward the shower. The same applies to any bench within the shower. Solid surface is best. ..........

Get yourself a very good contractor, with an excellent set of subs in plumbing and tiling. The DIY bath is very over rated, ninety nine percent of the time.

And yes........ I thought you meant with curb : ) Which is why I asked.

Yes, true and FLOOR depending. Either way...... completely waterproofed /pitched/solid surface.

"If the flooring is plywood then regular dimensional lumber shall be used of 2 X 4s to build the curb"

If you are talking about general trade practices then there may be some validity to this statement however the term "shall" should not be used. The curb can be constructed out of materials other than dimensional lumber. For example, the Schluter system utilizes an extruded foam product designed specifically for this purpose.

Thank you all for the info. I have also seen some tiled shower curbs. Would this really be an issue?

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Why would you INVITE an issue so easily avoided? A remnant chunk of quartz, of granite, of Corian of ANY solid in no way detracts from the looks. Tile the front? Fine. Save the grout for the vertical surfaces, the walls.

Schluter has a Lifetime Warranty when their system is followed. A lifetime warranty. Most failures are due to installer error. In any system.

Wood shower curbs expand and contract too much and are far too prone to failure from incorrect installation to ever claim them to be best practice. The consequences of incorrect waterproofing, including the incorrect use of wood as curbing material, gives rise to acres of pictures like this.

When curbs are incorrectly done, or incorrectly sloped, and water ends up leaking out onto the bath floor, you will have issues. A standard bathroom doesn’t need the floor waterproofed, but that means that you have to find someone who understands correct waterproofing. That is difficult to find.

Curb tops are always best as a solid solid piece of material. Even if done correctly, the grout line on a curb will take much longer to dry, and will be the first place that pink slime mold or mildew starts. Why give gunk an invitation to grow?

If you can tile the shower floor you can certainly tile the curb if you wish. You just need the appropriate waterproofing.

"If your having a walk in shower then either a fiberglass base to fit will need to be installed or a wet bed will need to be made. "

The shower curb can only be cement concrete based if the floor is a concrete. If so then concrete bricks will need to be used

You still need to create the pre-Slope out of Deck mud anyway."

Not true, bad advice

I can back up with written documentation from the company. All it takes for their Lifetime Warranty is a correct install, using their products, and documenting that install, then registering it. If it is not installed correctly, or documented, or registered, then they will still help you out. But all incorrect installations fall on the installer. As they should.

Schluter isn’t the only system out there, but that warranty is the best in the business. If you just follow their directions, and don’t do one of the jobs that end up in here as a dilemma.

Please feel free to document your work on here for illustration regarding industry standard best practices. If you wish to illustrate any points, you can also just link to the TCNA diagrams or pic of the page with the standard listed. Everyone is here to learn how to make their project be the best it can be. So, please illustrate and teach.

Unfortunately, none of these "Pros" have chimed in yet. What you're left with is decorators parroting information which they have little experience in. Millions of showers are framed with wood, but those little 4" wood curbs move too much and cause pink slime mold in the grout joints? Who makes this stuff up, the decorator's association?

I have four inch curbs all over the darn place. WHAT Slime? No client of mine has slime of any variety in any shower. Pitch to the drain. For gods sake, lets make wheel reinvention. Does this look like a slime "joint"?

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Does this???

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I can assure you, there is no slime. Nothing has move anywhere. Nor shall it anytime soon.Both are over four years old. Good GOD: )

There are two kinds of people who say that they "won't" use a technologically superior system. Those who have experience with a different technologically superior system, and want to tell you all about why their choice is better, in great detail on the specifics, or those who just can't follow the directions to do any system correctly. That's the type person that staples chicken wire to the wood curb, through the sheet membrane, which is flat on the floor.

This is why the choice of an installer is so critical. The Craigslist no name "Pro" with no or stolen pictures is not likely to give you a good result. Nor is the FB marketplace guy who has "been doing it that way for 30 years". Nor are those not open to industry education and learning. Or those with no ability to admit mistakes. (One of the best threads on one of the tile forum was titled, "Show us your beginning hack jobs") No one worth hiring is beyond humbly learning from their mistakes.

Good installers belong to industry trade associations. They attend industry training classes. A lot are at Surfaces this week. They own the industry manuals that establish the correct work standards. They follow the manuals, and they fully follow the directions of the system of choice.

They do so in order to give their customer the best possible warrantable result. They want to give their customers added value. When shown a procedure or system that makes their work better, they do everything possible to learn all about it, and to work with their reps to be sure that they have learned the correct ways. They are professionals. It is easy to sort the professional put your name on your work and stand behind it responses from the unprofessional ones.

ok, I am offically mildly freaked out even more in finding the right person to do the work.

I mean, unless I start studying up on how it's supposed to be done, and do research ( which is something I was hoping having to avoid doing, because I expect a pro to know those things), there is still a chance that the pro that I am hiring is still not going to do it the best way in the end. And unless I read up on it, there is no way for me to know if he did the waterproofing right or not. It feels like I need to study up on this stuff, just to make sure that the pro does it right. ugh.

@zealart - You are correct. As President Reagan said, trust but verify.

I just finished a remodel including gutted bathrooms with new showers installed. I spent a lot of time on the Board reading about shower construction and horror stories. I followed links posted regarding shower construction.

Much of it went over my head but I retained enough information so that I was able to ask reasonably questions regarding the materials used and how my shower was being constructed. I also checked out work done (including showers) by my designer and GC.

All efforts put into researching and learning as much as possible will get you the best possible end product. And not just in terms of actual construction - but taking the time to read copiously enabled me to learn about how I wanted my space to function and what products or design elements could get me the results I wanted in both design and functionality. I did have a great designer but it really is more of a partnership as I needed to tell her how I wanted my space to work - and sometimes there was stuff I read about on this forum that I was able to tell her about :-) - like my toe kick step drawers.

I also live in an area in which stuff is RIGOROUSLY inspected at every step by the City. My shower pan had to pass a 24 hour flood test for starters. I took pictures of my showers at various stages of construction which show the waterproofing and materials used.

I do know that my shower is sloped - I can even see where it slopes even more markedly by the drain. There is no puddle or even small remnant of water left when I finish. And I doubt any slime or mold is growing anywhere either since my automatic fan runs until it registers a low humidity in the bathroom.

FWIW, my curbs appear to be some kind of concrete and the curb is solid surface - constructed from a remnant of my counter and my bench is constructed of the same material. From everything I have read, solid surface for curbs and horizontal surfaces is recommended over tiles.

"It feels like I need to study up on this stuff, just to make sure that the pro does it right. ugh."

That is only semi correct. If you are going a self design and self GC route of hiring the trades yourself, yes, you need to do a lot of research. Sometimes months to years. You will be responsible for all quality control issues, and any issues that arise out of the products that you choose. You will be responsible for communicating the design and the specifications to the contractors. On the front end.

If you have a good Bath Designer involved who has prescreened contractors to work with, or a good contractor who can bring a great design sensibility and lots of product knowledge to the project, then they've will take care of the majority of the headaches for you. You only need to be involved in any hidden conditions issues that might come up and affect the design plan. Your Pros will sweat the details on the front end.

@zealart - This link will provide you with the questions to ask. My only post as I felt it was that important.

https://www.ceramictilefoundation.org/homeowners-guide-to-hiring-qualified-tile-installer

@live-wire-oak - Yes spent the week in Vegas at Surfaces. Educating and training others while learning about new technologies. All of my credentials are not listed on Houzz:)

Apparently folks are seeing through the bad advise and calling it out. Carry On. I have better things to do with my time.