Yes, you have the gist of what I am trying to do.

However, I got my dimensions mixed up with something else. The shower is actually 12 feet long x 4 feet wide.

While there is no curb along the 12' dimension there is a pane of glass along the threshold which separates the shower from the rest of the bathroom.

If memory serves me right there will be a slope that drops 2" over a span of 4' and it runs along the threshold as you suggested. However, a fixed pane of glass will run the entire span of the slope so there is no possibility of a tripping hazard. So as the slope sinks it will be behind the glass and perhaps look like the floor is slightly recessed. I think it will look OK but I can be convinced otherwise if people think it will be ugly.

The problem with sloping away from the threshold is that the shower is 12' long and that is a lot of floor to have to slope.

I'm attaching a diagram of the shower. It's not to scale but might help you visualize my situation. The gray area is where the floor will slope towards the wall and the linear drain is along this short wall. I left a gap in the perimeter of the shower to show where the shower entrance will be. The floor is flat at the entrance so there would be no tripping hazard.

Long story short, there is no tripping hazard but is it going to look bad? And can I use the TileIn type of linear drain which Quickdrain suggests using opposite the threshold?

Yes, what you want to do is absolutely fine

uscpsycho-

Despite what I said above, I have seen some curbless designs where the back of the shower is higher and slopes down toward the threshold where a linear drain is located...but that would still not be my preference. I also wanted to mention that the slope can typically be 1/4" per foot, so it doesn't have to be as sharply inclined as you mentioned above. Particularly with a lesser slope, I think it will look fine.

The right hand side has to slope to the drain as well, so your entrance would NOT be curbless. The entire shower as a whole, must have a single plane slope towards the linear drain against the wall. The entrance must be located opposite the drain if you are to have it be curbless. You can also place the trench drain in the middle and have two planes meet at the drain, but again, if you want curbless, the entry has to be at the top of the slope that starts the incline towards the drain. That is the only point where the two planes can meet and be level. If the entry is anywhere along where the shower is in mid slope, then the plane of the bath floor will meet the angled shower floor as a recess and will require a curb.

And this is regardless of the 12' shower dimension being completely oversized for humans and that it will be drafty and freezing. An equine care facility would probably even find it oversized.

This is the first time I've heard that all 12 feet have to be sloped if I want a curbless shower. Neither my contractor now plumber have said this. And the plumber was brought in for this one shower only as an expert on curbless shower design. Can someone else confirm that this is so?

That might be a good point though about the shower being drafty. I based my design on photos of really cool showers that I've seen. So far nobody has suggested in practice it would be cold. But maybe it's something to think about. Thoughts?

Goodness, my comment was made assuming you knew that the entire shower needed to be sloped because that is an inherent part of a shower. Think about it for just a second - if it's not sloped, the water will just sit there in a puddle and leave mineral deposits behind as it dries, OR you will have to squeegee the floor every time the shower is used and run the risk of water outside your shower. Apparently your plumber is only an expert in his own mind. Wow.

The building code requires any shower (the ENTIRE shower) be sloped between 1/4" per foot to 1/2" per foot on order for it to drain properly an not be too steep to stand on it or so shallow as the water won't flow towards the drain. Perhaps hiring some actual experienced design help is in order here. As well as a plumber with a non crackerjack license. It will save you from a 20K mistake.

Actually, I don't think that is right. I believe the code says that the drain must be 2" lower than the threshold and it must slope at 1/4" to 1/2" per foot. If this applied to the entire floor then every curbless shower would have to be at least 4 feet and could be no more than 8 feet.
I'll have to check but I'm pretty sure that your shower floor can be as big as you want so long as the slope at the drain has a 2" rise over a 4' to 8' span. If you want your shower to be bigger you can.
I'm not a contractor so I don't know for sure but from what I've read and what I've been told, this is what the code says. I have an unrelated inspection next week, I'll ask the inspector and get a definitive answer from him.

uscpsycho-
It's great if you can get some competent advice onsite; please re-post afterwards. I'm ready to be corrected, but I agree with others that you don't seem to be interpreting the requirements correctly, or that you are completely understanding how to construct this so that you have the best result.

Yes, to get a code compliant curbless shower, the width must be 4' at the steeper allowed 1/2" per foot slope with the drain at the rear. That gets your minimum 2" drop. Any shower or wet room must have the entire floor sloped in order to drain. Flat floors don't drain. Not understanding why you don't understand this or how you think you could have a shower with only part of it able to drain water.

Because there is one shower head at one end of the shower. There is zero possibility that water from that shower head is going to reach the other end of the shower. Water coming out of the shower head will ever make it past the four foot mark where the shower is sloped. I don't know what purpose sloping the whole thing is.

Also, having to slope the floor no more than 1/4" per foot means no curbless shower could be larger than 8 feet. I am pretty sure there isn't an 8 foot limit on curbless shows.

I'll ask the inspector this week and get an authoritative answer.

Ok, inquiring minds want to know what the purpose of an 12' shower might be if you only have a single fixture in it???? Do you actually mean that the 12' is the entire bathroom? Done as a wet room for some reason??

You're totally having some disconnect here in your math about the 2" curb thing. That's the minimum. It can be more. To have a shower or a wetroom be curbless requires both geometry and math to make it happen. Post your entire layout.

Bathroom is 12x12. Shower is 4 x 12. The bathtub is in the shower as well. Floorplan attached however the bathtub section is going to be larger now than what is in the drawing. The new bathtub is 5' x 6' so that leaves the shower floor area as 4 x 7. But the whole shower/tub area is all one open glass enclosure within the bathroom.

That is a pretty design. Not at all functional, but 15K worth of glass will be impressive.

You need to eliminate the giant ''shower'' idea. That much volume of cold or even just room temperature air around a wet body will be freezing. Really big showers have multiple points of water dispensing fixtures supplying hot water so that a person stays within the warm steam cloud and hot water. They also require commercial level hot water production for that many fixtures, and would not likely be allowed in your location anymore with the water rationing happening.

The tub isn't ''in'' the actual shower as the actual shower only occupies the small space to the left and the rest of the space is just an expensive waste. That smaller 4xwhatever shower (with the trench drain on the back wall) is what should be enclosed in glass. Then turn the tub the other direction so that it occupies the other corner and a glass wall sitting on the tub deck separates the tub and shower.

I can't read the dimensions, but you might have enough room to extend the tub deck into the shower as a bench and still have a 4x4 shower. You will want a hand shower somewhere in the shower (on a diverter) in order to at least clean and rinse all of that space. Gosh knows how you were planning to do that in the original version.

Now you have enough room for a linen closet to give privacy to the toilet area.

Not totally clear on what you're suggesting but if you wouldn't mind drawing a sketch I'd love to see what you propose. You do have me a bit concerned about the draftiness of the shower which I had not considered.

Blue is glass. Red is the trench drain. Green is the tub deck that extends into the shower as a bench. Use a knockout piece of stone for it and the back wall, and you have great visuals and great functionality without freezing to death. Maybe look for a couple of bookmatched slabs to use as the focal point, and starphire glass is a must.

I can only add my own experience: 150 sqft bathroom, including the 5'X7' open shower; glass from floor to within 1' of the ceiling on either side of a 3' wide opening to the shower; no problem with draftiness.

Not understanding why you don't understand this or how you think you
could have a shower with only part of it able to drain water.

They stopped teaching physics these days. The whole gravity thing and all...

The entryway to your partitioned area is too far away from the shower to put the drain there it just doesnt make sense, just slope the floor towards the showerhead and put the drain at the wall and you will be golden... or put the drain in the middle of the shower area only and do a V slope in the shower area.

I guess you could put a drain at the entryway as a backup just in case, but I would not make that the primary drain.

I see they also stopped teaching reading comprehension...

Where did you get the idea the drain is by the entry? I've explained, and clearly diagramed that the drain is under the showerhead and the floor is sloped to the showehead.

@kudzu9 You didn't explicitly say it but I assume the point you're making is that based on your experience you don't think I need to worry about draftiness?

Sophie, I appreciate the sketch. That won't work for me though, as I mentioned the tub is 5x6. Those are the physical dimensions. It's a two-person jacuzzi tub and it's already been purchased.

Also, the plumbing is in for the toilet so I don't think the orientation can be easily changed.

I can however, modify the shower/tub layout so long as the tub fits. And, as you can probably tell from the original design, I would like to make a bold statement. I have some renderings of this layout that I can post later when I have some more time.

uscpsycho- I was saying that has been my experience in my bathroom, which is roughly similar in size to yours. When I am in the shower, the exhaust fan is running, but it's not drafty. I'm not representing myself as the final authority. I just thought you might benefit from hearing what I have experienced.

Yes, much appreciated. Oftentimes real life practical experience is as valuable (or more valuable) than text book advice.

Here are a couple of renderings. The slope for the drain isn't visible and the colors are generic. And the shower isn't to scale because this was produced before I bought the large jacuzzi. But this is the idea.

With this configuration, you most definitely need the ability to have more than one shower head's worth of water hitting you. I have a 4' x 5.5' shower with a window in it that is a little bigger than yours. I'm in Texas, so its not exactly cold country. I have a regular showerhead and a handshower on one wall and two Kohler 'shower head type' water tiles (the built-out angled type) about 18" apart on the other side. When the water tiles and shower head are all on, they overlap in the middle and you can stand in there with water all over your body, but your head out (great for us females that want to leave in conditioner :) ). The two tiles together, the shower head and the hand shower have individual volume controls with a single 3/4" temperature control valve.

I run all the shower heads all the time except when I'm soaping up my body. If I don't, it gets chillier that I would like. I would never, ever spend that much on a bathroom and not have the ability to have as much water as possible hit my body. I'd get rid of the tub and the TV and a sink and the wood floors and probably the bathroom door before I'd get rid of some of my shower heads. (I'm not criticizing you for having things like a wood floor and a TV in your bathroom; I have a wood floor in mine too, but no TV -- but only because there's no place to put it. I've probably spent more on my TV equipment than anything else in my house!!!)

Oh, and I have a regular-sized water heater and I've never run out of water, even after my teenage son takes a SUPER-long shower on full hot (what?), then I take one.

That design ^ is completely undoable from a practicality and functionality standpoint. Water damage and a red tag waiting to happen. Get a local CMKBD involved who understands math, geometry, and materials' properties.

I seem to be comprehending it better now. As far as the wood design, you could use tile that looks like wood planks instead of actual wood. Those usually look pretty nice, and you wont have to risk future water damage problems.

Concerning the drains, I am thinking you do actually need two drains there to make it work. One at the threshold as a backup and one running the length of the shower so they can slope it properly and it not be too big of a slope. If you slope it towards the showerhead the difference at 1/4" per foot for 7 feet is 1-3/4". That's quite a bit of a slope and as sophie said, probably not doable. If they do a v slope into a drain at the center running lengthwise, you only need to slope for 2 feet at 1/2" drop.

My goodness. This thread has gone off the deep end.

First of all, simultaneous water sources are not allowed in CA. One at a time only. And even if I could, I wouldn't. I conserve water at every opportunity. I know that until very recently Texas was in a severe drought so I hope you only recently started wasting water with "SUPER long" showers and multiple water sources. These days this kind of behavior is frowned upon in much of the country even when there isn't a drought condition.

None of the surfaces in the renderings are true. I said the colors are "generic" meaning don't pay attention to any of that. Maybe that wasn't clear but there is no wood in the bathroom so it's not a concern.

As for completely undoable, you guys have lost your minds in terms of the drainage needed. There is one showerhead with a full four foot long linear drain under it. And for the next four feet away from the drain there is a downward slope aimed at that drain at 1/2" per foot for a total of 2" rise. The entrance to the shower is another good foot or two away from where the slope even begins. There is no way water from a low flow showerhead is going to travel four feet uphill, then traverse another foot or two of flatland and then follow that by making a sharp right turn to exit the shower. Not. Going. To. Happen. At least not on the planet Earth. I don't need two drains.

I was not questioning if the shower design was OK. I was questioning whether or not a certain type of linear drain could be used in this design because the manufacturer's verbiage was unclear. I have spoken to Quickdrain and they assured me that the TileIn drain and WallDrain will be fine with this design. And these are their least capable linear drains.

I suppose there is a question about whether or not code requires the entire floor surface to be sloped but the people working on my house have done curbless showers (one guy was brought in specifically to do the shower floor and drain because he is a curbless specialist) and they don't see an issue. I will still ask my inspector when I see him to be sure.

I might actually prefer the entire surface to slope back towards the wall and away from the door just so that the floor of the shower is seamless. I hadn't considered that option but if I do it, it would be for aesthetic reasons not because what I have will not contain the water.

Where will the water that hits the flat surface after the slope drain to? You stand a certain distance away from the shower head. The water hits you and then bounces off in all directions. Some of the water will probably land on the flat surface and then just sit there since there is noway for it to get to a drain. Plus, I would like at how sharp an edge you get between the area that is sloped and the flat surface. To bare feet, it might feel sharp.

I use the water on my body instead of most of my 1/3 acre property. We average 3700 gal per month (according to my bill). That includes July->September when I have to water my red oak 'forest' to keep them alive; so our usage goes super-low in the winter (<2k per month -- gotta keep that wastewater charge down!!). How many more gals per month do you think people dump on their lawn (even with only being able to water 1x/week) than I lay on my body? For all of Austin, the average is 137 (!) gal per person per day. That would be a whopping 8220 for us. So, even with my son's penchant for super-long showers, you're really going to complain about that when our average is 45% of the Austin's average?

The super-lowest average in CA is the bay area with an average of 57gal per person for day in January. So, for a 2-person household, that's 3420. In January, we used 1400 gallons. That's 23 gallons per person per day. ~40% of the super-lowest in CA.

What's your average?

BTW, I know exactly how much water it takes to keep my lawn looking nice when its 100 degrees and doesn't rain for months. Its about 20k gallons (according to my bills from '08 and '09). My consumption has been reduced by 91.5%. The showers? Seriously?