Our shower that is in progress right now, is 5' X 5'.

FYI - we debated whether a central drain or a linear drain. My contractor said that if you are turning or being turned in a wheelchair, you kind of "fight" with the floor more if the drain is in center.

Plus aesthetically, if you have a central drain, you almost must use a mosaic tile for the shower floor. In your case, changing to mosaic for the shower wouldn't change the aesthetics very much. In our case, where our bathroom is smaller and there is one visual line from bathroom door through the shower door to the other side of the shower where there is an awning window above, breaking up that visual uncluttered perspective looking across the floor wouldn't be so good and since it was doable, that's what we chose.

FYI - we went with a pull down bench from Invisia - don't have it installed yet. Aesthetically, it may not be as good as a bench but I heard several people mention here how a bench made out of tile is "cold". The wood in the pull down benches is not so cold.

Also, we have radiant floor heat. Even in our warm climate, it was suggested to me that a large shower can be "drafty". Our radiant floor covers the whole bathroom floor, not just the shower and I'm expecting to be very glad to have included it. We have central air/heat but no wall heater in the room for those extra cold times. Our house is old (built in 1935) so I wanted the extra warmth.

And one last thing, if you haven't finished your design, you might consider the Moen Idigital spa where you control the fixtures with a touch of the button. I heard about this here and after researching, found that many have it. The control panel (with 4 preset buttons) will be easily reachable from the bench. I think I am more excited about using this digital shower control than the other features of the bath. But it also seems like it will be quite useful as a feature for a disabled person which I am not yet - though I do have some balance problems now and then.

Forgot to mention that it was reported here (I think or maybe somewhere else) that the radiant floor will help dry the shower floor. I'm also not planning to use a bathmat - something else to get in the way or trip on so all the more reason for radiant heat.

And you have a closet like us on the other side of the wall from your shower. At least for us, that seems to be an optimum place to install the Moen shower valve for troubleshooting access if and when we need it.

And one last thing, LOL. I would recommend you make sure there is an outlet near the floor on the side of your toilet if and/or when you might want to have a "washlet" installed. My plumbing fixture lady has one and she is not handicapped but says she loves it. We won't have one in this "phase" but if we decide later to put one in, we will have the plumbing and electrical ready for it. Seems like a "washlet" would be specially useful to someone who is disabled.

The drain to the shower must be 2" lower than the entry point. The overall slope must be 1/4" per foot. That math works out to being if you use a trench drain at the far wall in a 4' shower, you will have satisfied the code requirements. If this is to be a wheelchair accessable shower, then it needs to be 60" x 60".

Putting a drain to a curbless shower at any other point and make it smaller means that you will have to treat the entire room as a wetroom. That costs a whole lot more, and is more difficult to engineer. Doing just a curbless shower to code is difficult enough task to be able to engineer for most contractors, so I'd not do the wetroom unless I had an excellent contractor.

You may find like I did that precise specs for an "ADA shower" are a bit hard to find. The "2 inch lower than the entry point" spec appears to only apply to a shower with a curb. I don't have knowledge as hollysprings but on this particular point, I carefully covered it with my contractor and also here on the forum where I received invaluable info from Mongo. Turns out that ADA specs can even change according to your locality. You may be like us and looking for helpful guidelines for disabilities rather than worrying too much about whether you are following precise code. But I would recommend you read the invaluable input from Mongo at this thread here (scroll down a bit) --

http://ths.gardenweb.com/forums/load/bath/msg1214325929991.html

Thanks Elphaba and hollysprings!

That is very helpful information and insights.
We were planning to use a mosaic floor tile, which sounds like it gives us more options. I am wondering with our dimensions and entry doorway to the shower, if a central drain will have enough slope or if a Linear drain along the back wall or part of the back wall would be best? Given that we have a 4' 10" width and 5'7" length (measuring from shower seat). Or is their enough room to place the linear drain away from the wall and more central location?
Thanks again

(Any negatives to a linear drain? any issues with cleaning or stoppage?)

The linear drain is more expensive than a central drain. If you don't install the linear drain along the wall or at the entrance of the shower, you lose the advantages of the linear drain. Besides making for easier wheel chair turning, it also has a more elegant look IMO. I have been lurking in the forums for a year or more and haven't heard any complaints about linear drains clogging. This might be a good question for the plumbing forum - those guys might know more about frequency of calls to unclog a linear drain.

Locating a linear drain under the shower door is something I've read that others have done but I don't know anything about that first hand. But apparently it is an option for this kind of config.

Doesn't look like your doors are 36 inches wide. If you're doing this for aging-in-place, I would strongly recommend you re-think decision not to widen doors if you have that option.

You indicated that the contractor was going to "lower" the floor which tells me that this is a remodel instead of a new-build. Otherwise, I would be tempted to offer some layout changes. My experience with layout is minimal but you might get some really nice config suggestions if you asked others in this forum.

Good luck with your bathroom. I am thrilled with the progress in ours and I am VERY glad that I did many, many hours of planning (and reading on forums) before the construction started. Don't let anyone tell you you are "over-thinking" this. There WILL be surprises but oh, thank goodness that I did the planning because that minimized surprises considerably - so far.

We don't have the money for a "do-over" so this is our only shot.

Another option is to install the linear drain along the
"seam" at the base of the bench (if you are still planning the wall to wall tile bench) - seems like the drain there would actually be closer to your shower fixtures and where the water originates - just a suggestion. (I think I saw a picture of this style on the John Bridge tile forum.)

I went looking on the John Bridge tile forum for the linear drain photo I thought I had seen there (some time ago) and found this info below - so didn't want to think I had misled you about locating your drain at the door. Apparently if one finds the info below factual (need to do your own research), only in an ADA curbless shower is your option for locating the drain at the door likely not to require a waiver - (please note my use of the word "likely") - but if you took the ADA approach, you would need to change the size of your shower - to 5X5 with options to enlarge depending upon your local ADA code.

"If you want your drain at your shower opening with no curb, you'll need a variance or waiver from your code compliance jurisdiction."

Your "better bet" is to have the shower floor slope away from the entry and to have the linear drain on the back wall of the shower. That will allow you to minimize floor slope to get the required 2" drop if you are required to have a code-compliant shower.

There are no out-of-the-ordinary issues with linear drains stopping up or clogging. An occasional problem with them is having the drain at the shower entry. Sudsing action from soap/shampoo can sometimes cause suds and water to sheet right over the drain's grate and puddle out on the bathroom floor.

There are some locales that prohibit trench drains at the entry to the shower.

The idea of dropping the floor framing in the shower is an excellent idea.

If you do go with the drain at the shower entry, use a membrane to waterproof your bathroom floor out a few feet away from the shower entry.

With a linear drain you'll be using a topical membrane throughout the shower floor. That can usually be carried out onto the bathroom floor.

And one clarification regarding your post:

"The contractor says he will lower the floor (via the floor joists) to be about 3in lower than the bathroom floor then build the shower floor up with mud?. He says the initial entry to the shower will be flat and then slope downward to a central drain in the floor.

Then:

"The linear drain would be placed under the shower door where the entry to the shower begins. "

Is that a description of two different showers? The first being with a central drain, the second with a linear drain? The thing is, if you're going with a linear drain at the shower entry then you really don't need to drop the framing in the shower at all. You can pretty much build the "upslope" right on top of the shower subfloor that is the same elevation as the bathroom's subfloor.

We put a zero entry shower in a few years ago and we love it. Mongo is right (always : ) ) put the drain at the far point. I had no choice with mine as it was existing construction, I had to put my drain at the shower door. Not ideal for many reasons, one is, you will always have to open your shower door out as pushing in will eventually hit the tile floor. It's ok once you get used to it yourself but scary when you have others stay at the house. Yikes! The way I understand it, you need a 2% slope. I remembered this as being 1/8" to 1/4" drop per foot. Not sure I looked it up and found this quote. "2 percent equals how many inches per foot? For every 50 inches the slope changes 1 inch. so for 1 foot it would be just less than 1/4 inch I oreded my drain and supplies from Quickdrain USA their web site looks a little different now. But they do have lots of drawings and helpful hints. So go there and study them. I purchased the dense styrofoam from them. You thinset this down ontop of the plywood floor in the shower this sets the slope for you, very quick and easy. On top of this you put knoble waterproofing membrane (thick and blue) and it matches up with the knoble flange that is around the drain. I purchased the Knoble membrane, styrofoam drain, knoble caulk all from QD. I had to call Knoble directly for some questions and they could not have been nicer. I did the walls in Kerdi but could have used Knoble. I would suggest to make the drain the full width of the farthest point where you're placing the drain. I wish mine was the full width of the front of the shower, it was suggested to me by QD to just make it the door opening. Oh and I made the entire room a wet room. With the use of the Deitra to stop cracking of the tile. There was something else I wanted to say but can't think of it now......

Thanks everyone: All your inputs have been very helpful and will allow me to discuss with the contractor more pointedly and with some useful knowledge.
The joists are not I-beams. GC says he will discuss a linear drain with the plumber.

What about the shower door not being able to clear, or travel over the shower mat/rug?

Thanks again!

If you slope in towards the back you will be able to swing door in and so door mat will not be an issue. I remember the one thing I had on my mind the other day. We were existing construction so we had to deal with it. One of the things we ended up doing was dropping the trap much lower then you would see on a normal shower drain. The thought was great the water will have no choice but to MOVE. The result of that created a very loud drain. It made kind of an echo chamber, something to think about and to try and avoid. It's not horrible but it could have been better.

what about lower shower floor 1" and put a teak shower mat over entire show to bring the floor flush with rest room? this way you don't worry about where to put drain and still keep water out of shower? I am planning master bath reno as well, I am think the same thing

Unless you have a physical need for a zero entry shower, I would caution against it unless your tile person has done LOTS of them prior to your house. We are having to rip out a 3 y.o. shower on our newly purchased home due to a defect in the existing zero entry shower pan (which leaks : (. Be extremely careful in your selection of a tile guy. We're opting for a curb this time around...better not to be a part of somebody's learning curve while trying to chase all of the newest design trends.

There are other uses for no-curb showers besides older users. Some have dogs. Some raise plants. Some have little kiddos who shower together. Always easier to walk right into a no-curb shower or roll something in.

Everyone has a different way of spending in a house. If an accessible shower in a bath makes it cost a little more, that's a decision.

Berta1283 I am sorry you got burned with your leaky shower, but you probably would have issues with a curbed shower with the installer that you picked. The principle is the same. We did ours back when there was not a lot of them going in, but through the great folks on the garden web (I go way back) it was our first and it was perfect and will last a very very long time. I urge you to go over to JohnBridge website where the bulk of the tile guys hang out and start reading, and reading because even if you don't do the work you should know what is the correct method. Unfortunately, that is the way things are today.