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.

Thanks everyone for your helpful posts! Apologies for my absence. Our modem went out and we finally made it to our internet provider for a replacement. For some reason I couldn't post back to the forum on my cell?? At any rate, my internet access is back! I talked to our contractor again and asked if we could drop the slab or raise it when they pour the concrete slab. He said he will talk to our tile guy to see about raising the floor when it is replaced since so much of it will be removed during the process. I also mentioned making sure the waterproofing is extended to the main floor and he said they would definitely do that if we do end up going curbless. I'm ok with putting in a glass door and a partition to keep the water in. I should hear an answer back from them soon whether they can do it and any extra costs that we will incur. The cost of removing so much concrete and replacing it was already included in our quoted price. We are switching the location of the toilet and the sink because the toilet was directly in front of the door. We expanded the bathroom and are going from a pedestal sink to a 60" vanity with double sinks. Also, the shower drain is being moved over since the bathroom has been expanded. Having the information from you all has helped greatly. Jerzeegirl, love your shower. The row of black tiles on the bottom is a nice touch! Lori_inthenw_gw, I will PM you for a photo. Thanks for the info about the shower spray. I would be ok with that if I can do away with the curb.

Megan it’s unfortunately a really serious mess. I have to say I’ve been reading Houzz forums for years and have seen some really bad tile installs, and this is one of the worst, if not THE worst, I’ve ever seen. There’s just no way that what’s under that tile could be correctly done. It has to be completely torn out and redone from scratch by someone competent. It is true that the type of entry you want is more difficult than a curbed entry, and it will and should cost more because of the time and skill it requires. But this person is so incompetent that I wouldn’t let them redo the work even if you switch to a curbed entry. When it is being torn out, take the best pictures you can of what’s underneath, layer by layer. Also take excellent pictures and video before it’s taken out, and if any of the materials the installer used are still in your house, take photos of those as well. Get any markings or labels that identify the materials into the photos. All of this will help you prove the installer did not follow the TCNA standards Dragonfly showed above, so you can hopefully recoup anything you’ve paid, and get out of paying the rest. I would also find a really good tile installer (I’m sure you thought the first one was that) and see if you can pay an hourly rate for them to come look at this before taking it out. Ideally get something from them in writing about the quality and correctness of the work. I’m sorry you have to deal with this.

Bill- Don't carry the underfloor heating into the shower. From a thermodynamic standpoint it does nothing: the water coming out of the shower head will overwhelm any contribution it makes in a second or two. Also, if it is the type of underfloor heating that consists of electrical mats, you don't want it in the shower: if there is a break in any of the wires at some point, it can pose a shock hazard.