We LOVE our curbless shower. It WAS expensive. We have a pier and beam foundation. I don't know exactly the inches but I learned that because our shower was 5 X 5, this made it so it could be identified as an ADA compliant shower - no larger or smaller works for this label - must be 5X5. Once you are ADA compliant, rules can change and in some case are more lenient as far as the floor slope. You need to check your local code. Don't want that wheelchair toppling over, I guess. We have a linear drain on the far wall away from the shower opening (3 ft wide) and which always drains well with no water coming out the shower opening (we chose not to put in a door and not having a door adds SOoo much wonderful ambience, it is great) and though I don't know inches precisely, there is no way it is a 4 inch drop on the tile floor. Maybe beneath, it took four inches but I doubt it since no "shower pan" as such was used, I'm pretty sure just Schlueter waterproof sheets/products were used. We also had radiant floor put in to keep any possibility of drafts down in the winter. But I'm obviously not into the details on this very well and got help from Mongo on some of this so I will defer to him on the contruction details. But I would like to say most importantly that the 5X5 is a perfect size and we wouldn't really get any more enjoyment from an 8X5 but your mileage may vary. I can be using the fixed shower installed on one side of the room and easily reach across to the hand held shower installed on the opposite side of the room at the same time. Room enough for two. AND turn on the rain shower in the middle. Fun, fun, fun. And because ours was 5X5, we had space to put a closet on the other side of the wall of the shower for use in the adjacent room. Closet also gave us a place to install the Moen idigital shower valve and access panel. This really allows the shower walls to have a clean look and adds even more fun to the whole process of showering, IMO. It was quite expensive but if we had to make the choice again, we would still choose the curbless. But make sure your contractor has experience cause I definitely got the impression you want someone who knows what they are doing.

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.

Another barrier free shower. This client requested Kerdi but I used Kerdi DS because Kerdi is just too thin for my liking. This photo with overlay shows some of the planning that goes into a proper wet room. Things are rarely flat. This job the client ordered a linear drain from Proline and a steam shower from ThermaSol. More info on planning: STEP ONE - BUILDING A BARRIER FREE SHOWER To make the temporary flood test I used some banding and some Ardex 8+9. Anyone building barrier free showers for you should be able to show you a dozen examples of the work. I could go on and on but you should get the point that there is more than one way to skin a cat. In all of my builds since day one I have never found one system that can do the job start to finish. It just does not exist. As a warning I would suggest that the advice you follow online come from people you can prove do this work for a living. No doubt there will be loads of advice given out across various forms. But with a little digging you will find 95% of the posting coming from "Pretend Builders" or people who google info and then act like they do this work for a living. You are in a high risk massive downside build. Make sure the people you hire or talk to for help do this work for a living. There is less than 12 people online with the skills and the know how. Here on Houzz we can not debate our facts or our work practices. So if you read info from one poster that is wrong and someone else offers up another point of view you might muddle some false facts with some proper advice. Pick and choose the advice you receive. And do a simple checking of the other posters work. You will find like I'm sure that most of the most active writers in fact never have even tried a job like your attempting. These jobs are extremely challenging to plan out. The tile layout is key. I'm finding more and more clients are enjoying this help from my mini shower design calls. If you need more one on one help please take a moment to study the reviews I'm getting on Houzz. The skills learned from building and screwing up curbless showers (which I have done in the past) are valuable lessons. Many of the showcased showers on Houzz here may in fact be failing from day one. The work that goes in behind the scenes is key.

I would also go around looking at new build homes and what they are selling for. That will give you a very general idea of what is included in each price point in terms of how the house is finished and what you might expect in your price range. So using my neck of the woods for example (SW FL), at price point A, ($150,000-$300,000, 1500-2000 square feet) houses have minimal or no interior trim. Floors are basic carpet in the bedrooms or vinyl flooring. Whirlpool appliances, builder basic cabinets with no pullouts, formica counters, builder basic white windows, basic light fixtures, etc. The paint on the walls is all the same color, and the finish on the walls is a knock down finish. Bathrooms are finished with prefab tubs and showers and minimal tile work, if any. At price point B ($400,000-$650,000, 2000-3200 square feet), floors are tile in public rooms and either carpet (a higher grade) or tile in the bedroom, there is some crown molding trim and maybe trim around the windows, the appliance package is upgraded to something like GE, cabinet's are semi-custom with maybe pull outs in the lower cabinets, level 1 or 2 granite with a 4" granite backsplash, windows are better than builder basic with maybe a beige, white or bronze exterior color, light fixtures are definitely more decorative, etc. There might be two or more wall colors and the finish on the walls will be an orange peel finish with a knock down ceiling finish. Bathrooms are finished with drop in tubs and tile work only on the shower and tub walls. At price point C, ($700,000- $1 million +, 2500-? square feet) floors are wood, with marble in the bathrooms. Trim is quite detailed, including specialty trims going up the stairs, in the dining room, etc. There are specialty ceiling treatments. Appliance package is Wolf or better. Cabinets are custom with drawers for the lower cabinets and in specialty finishes. Counters are quartz or quartzite with tile backsplashes. Windows are custom windows. Light fixtures look like they came from a decorator. Rooms may be painted in more than one color and the finish might be anything from an orange peel finish on up to a level 5 finish. Bathrooms are tiled in marble with decorative floor and wall designs. There are soaking tubs and glass shower enclosures. And of course within each price range there are different levels too. And when building custom, even within each level except maybe a truly million dollar plus custom home, there will need to be compromises. For example, do you want a smaller home with higher end finishes or are you willing to give up some of the higher end finishes for more space?