Are you saying the entrance comes in from the left of your photo and the oversized linear drain is under the bath floor tile? There are several visible concerns. A photo from further back would help.

I have a major concern with that installation. While linear drains have a large surface area compared to regular central drains, and don't clog up frequently, all shower drains need to be cleaned out periodically. I have a tile-in linear drain and it comes with a little tool that I use about every six months to hook onto one end of the drain insert so I can pull it out and deal with accumulated hair and grot. It looks like your design would have a glass panel installed over the top of the linear drain which would prevent this kind of preventive maintenance. Do not allow this: I guarantee you will regret it. A linear drain should be sized to be as wide as possible (typically only an inch or two narrower than the shower space), but certainly not wider than the space with a design like yours. I can't think of a good way to remedy this other than removing what you have and having a properly sized drain installed. At least you caught this before the tile went in.

Thank you! We feel the same. Think the contractor may say he will cut the top down to size but then we still have the drain pan extending under the regular floor tile. Makes no sense. Thanks for your input!

@creativetileeasterct thanks for your comment. Here are some addition pics to help with the overall view.

Cutting the insert down to size would mean two things:

1. He would be tiling over a void space where the pan still extends under the glass. Hmmmm....

2. He would be cutting off the raised rim on one end of the insert that holds the tile (typically the insert piece has a raised edge on all four sides that form a perimeter for the tile. In my opinion this would weaken the structural integrity of the insert and thus make the tile more prone to come loose on the exposed end because the insert would have more flex in it.

The contractor is proposing a bastardized approach to avoid having to remove the existing pan and patch the hole. I can't say that this would absolutely fail but, personally, I wouldn't find it acceptable. It's your call, though

Agreed on all! Thanks for validating our concerns. Will definitely ask him to fix. I think honestly he messed up the shower width and didn’t realize. Will make sure it’s fixed.

The only other thing I can think of -- if you have enough room -- is moving the shower glass to accommodate the too-long linear drain. If not, get it done right....

Thanks kudzu9. Moving the glass isn’t an option because we have a skylight above (glass is to be lined up with the edge at the ceiling) which is precisely why the shower dimensions never should have even been a question for the contractor. Also the vanity is custom and complete and has 1” of room between the end of it and the shower. We have drawings and specs taped around their work room.

Concerns - (I can't determine from the photo's)

1) Shower appears to be 6' wide based on visible 12x24 tile. This would mean that the shower floor slopes from right to left @ 1/4" per l/f. That places the linear drain 1-1/2" below the bathroom floor requiring a tapered profile trim.

2) Kerdi system mixed with Redgaurd = no manufacturer warranty? You may want to call manufacturer to verify.

3) Is that a Kerdi linear drain or another manufacturer?

4) No waterproofing membrane at Kerdi membrane to heat mat.

5) Is your custom vanity a open design? A vanity with a closed in base can't have heat cable underneath.

6) The linear drain extending under the bath floor tiles goes into the "Never say you've seen it all" category!!

Thanks so much @creativetileeasternct For q 1/2 I will double check thank you for pointing out. For 3 I believe it’s a schluter drain.

4 - what would the waterproofing look like between Kerdi and heat mat?

5 - the vanity is open with 10” between the floor and bottom drawer

6 - all I can do is shake my head!! We willl get it fixed and check on the above points. Thanks again!

That Frankenstein isn't even built properly. Put this on STOP until you find someone to fix it. Or start over.

I've been planning for a similar solution (Kerdi Schluter with tile and linear drain) for my bathroom renovation, and it requires a specific design solution to work properly with a low curb or zero entry. For example, we are planning for a recessed floor in the shower area so that we can get the required 1/4" per ft slope to a linear drain along the back wall. That had to be specified in the architect's plans so that all the floor elevations will come out right when they install the floor joists and sub-flooring. It gets even more complicated with a side to side slope to a linear drain, since now you don't have a flat entry across the shower front. Its not something you can fix easily in the last couple of steps.

We also specified Kerdi waterproofing under the bathroom tile outside the shower, due to the low curb entry.

Bruce

Kerdi band membrane would cover the transition from shower base to heat mat. The band would also be applied to all seams in the heat mat and from mat up onto drywall around the perimeter of the room. All good with the open vanity. Check that slope!Use the product manufacturers to back up your position in writing, email etc. These folks don't like their products used improperly any more than you. I can't speak for their official stance on combined systems. If you have any photos of wallboard prior to tile that would also be helpful. Keep in mind I'm not saying combining systems won't work but you need to protect yourself with a warranty. Don't fall for the lifetime warranty BS so they can sell more product. Quality mortar manufacturers which have been around for a long time will stand behind their products over Kerdi and other systems.

https://www.ceramictilefoundation.org/homeowners-guide-to-hiring-qualified-tile-installer