Do you know the term "wet room" ? I wonder if "wet room" bathrooms have a graded floor. Methinks it needs a floor drain to make sense.

Yes it can be done, and yes it has been done.

In one bathroom at home I sloped the floor from the marble door sill to the opposite wall. All in one flat slope to the wall. I added a floor drain too, and it's hidden under something else so only homeowners know it's there. The drain is not in a corner, so to get the water to go towards the drain, there is a secondary slope (very minor). The goal was to shape water flow (where water pools) and not to have a floor draining as efficiently as a shower floor drains. The slope is less. One still has to push water into the drain, e.g. with a squeegee. Imena like Whenever there's a huge amount of water. We often squeegee the shower floor, by the way. If we didn't there would be a little bit of water pooling around the drain for a time. In the bathroom there would be a bit more, along that back channel, because its slope is not steep.

In another bathroom I sloped the floor, in the same manner as above, all in one flat slope. This time the drain was in a corner. It's also hidden, or partially so. It works about the same or better. That bathroom doesn't get wet as often.

In both cases the slopes are not perceptible. Guests don't notice it. Not even design professionals.

Without a drain, it can still be a good idea.

There is no added advantage to the electric or hydronic floor heat, in my view.

I'll spare you the details about how I built it and why I chose these great products and who I brought in to look at it in progress and how proud I am now to have an invisibly sloped floor in my "wet room" bathroom.

John, Forgive me if I misunderstand you, but it sounds like you floated a mud base over the wire and THEN used Ditra as well? If you're doing a mud base, then the floor should be properly graded as it's mudded. If not, there are times, such as when doing older buildings and the floor is 2" out of whack from one side to the other, where grading the floor is probably a good idea, so long as you can resolve the issue of any height difference at the door. But in most cases, there's no need to grade the floor. In most construction, it's not nearly far enough out of whack to really make a difference.

Now, that all said, if you DID do an actual mudjob on your floor, aren't you way over engineering it?

The over engineering Bill came from my Ditra Install. Because I used a few off cuts and choose to use Kerdi Band across my Ditra seams there was slight ridges left from a less than perfect hand floating the floor (Mine :o).

My master setter Bruce is a "Hard Ass" he failed my prep when he came to set the floor and reminded me he told me to make it perfectly flat for the small 2" Hex tile. He knows how picky I am and offered to grade the floor like I want and prep for the Hex tile at the same time. Now I have to set the floor with my boys.

What a difference in skill set! Bruce put me to shame. I have no excuse for a bad install because Bruce left me with a perfect base.

With the height difference at the door Bill I cheated the subfloor slighting in front of the entry about 4.5" out. I used some sill gasket and tapered cedar shim ends to gain 1/2" at the center point of the door. I think I nail this part.

It is very humbling being show up by my subs - that's why I hire them. My roofer and Sidewall guys did the same...

I will use Bruce's technique to grade my en suite once I catch my breath and like Davids Idea of concealing the second drain in my "Wet Room Master En-Suite". I'll plan on using a second Kerdi drain as a secondary drain (concealed below vanity) and for my primary drain line a Channel Drain from Quick Drain USA or CeraLine at the showers entry.

I think all this effort will help to keep those puddles from hanging around at the edge of my little ones bath. And I think as well it offers up a little more character - even if it is just a small detail.

My plan...

JW

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You can see the slight grade at the edge of the tub. I installed a double layer of sill gasket before doing any floor prep to built in a thermal separation and expansion gasket. The seam between the tile and the tub will be Kerdi Fixed or siliconed and water running down the tub side should slowly move towards the center of the bathroom under the bath mat - where it will dry out from the floor heat.

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I designed the vanity to be a stand along piece and will have an open back and 6 drawers. The P traps will run along the wall and the plumbing connections will all be visiable when the drawers to the vanity are removed.

I want to run some sort of flashing or kerdi under the supplies so that if I did have a failure down the road the water will run out from the wall and down to the floor and right to the middle of the room where it will be noticed at once and not years down the road.

This concept was taken from the fine engineers at DornBracht. Most of their line is designed this way. Truly Brilliant - So German - So well thought out. After seeing the wisdom on my last project I have taken measures to allow my basic American Standard fixtures work the same way...

Some curbless showers and level access showers built with my help here in Vancouver over the past 3 years...

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So I'm not still confused David. Is this what you mean by "Wet Room"?

I have been using "Curbless Showers" as the term mostly.

I'm sure your right. It must be a "Wet Room".

Thanks again for all your insight. Would love to see pictures of your projects one day in these pages.

How did you prime your hidden drain? Do you have any problems with self priming traps? I thought about installing the P Trap in the floor joists and having and access panel at the bottom of the vanity that was like a hatch so I could bring my floor waterproofing up above the 2" mark.

Any insights here?

"Wet Room"

Using the same skill set that brought you here, web searching, use the term "Wet Room" as a key word. The two words go together inside quotation marks so the search engine knows to look for them as two-words-together not just as wet in one place on a page and room somewhere else on the same page.

hth

Thank you davidro 1, for pointing out the need for a bathroom floor drain, whether its hidden or not, because something will eventually break (toilet or sink) and water will be everywhere, so why more designers don't plan for this is puzzling to me. Two weeks ago, a 3 1/2 year old was proud that he flushed many of his toys down the toilet. Needless to say, the hardwood floors in the next room and the suite down stairs were damaged. A floor drain would have caught and drained away most of that water.
I advocate for a floor drain in any room that receives water, bathroom, laundry room, kitchen, and hot water tank (utility room), because its not a matter of if, its a matter of when the water will break free.
Good Luck

In Australia and many places in Europe this second floor drain is a most and required by their countries "Plumbing Code". I think these second drains should always be used with a channel drain / curbless shower installation.

I reviewed this subject with my local plumbing inspector and he informed me that a plumbing system designed and built properly to code does not need the second drain to pass inspection.

"But is it a good idea?" I think so.

David's concealed drain the most applying concept to me so far! - buried under the vanities kick or deep behind a free standing or floating piece (a second channel drain up tight to the baseboard?).

Some of the options for designer drains available through California Faucets are amazing - all the top bathroom shops carry them.

This second drain and fail safe would offer up better protection if a clog caused by blocked hair, wash cloth, foot, toys ("Little People & their stuff") went unnoticed in the Peak of Play Time. There are issues with priming this second drain line and many was of doing just that - have a ticketed plumber help you with the lay out to be approved by city hall.

My kids bathroom floor is heated and I slopped this floor a hair so dripping water would not sit up against the tub base and baseboards (Wood).

If a drip or slow leak happen I hope this will bring it out to the center of the room for us to notice and repair. I designed my daughters vanity piece to have 6 drawers, 2 sinks and an open back to work on and service the plumbing connections.

In my en-suite I will rip up the floor and follow David's advice on a concealed back up drain. This second drain will cause my curbless shower to have compound angles so I'm thinking we should look at a 4"x4" tile or smaller for the floor.

More work....

Safer....

Nice....

Perfect.