I paid the extra money to have the tub deck cut as a single rectangle.

The reason it was extra money is because it was extra labor and transportation to be very careful so that it wouldn’t break while they were bringing it in.

But the middle of the slab was cut into other pieces for the shower curb, bottom of the niches, top of the pony wall, the window sill, etc. You can use the middle part to cut out other pieces you need for other places in the bathroom.

Thanks for the info - I have asked to have it quoted both ways (single piece, and multiple pieces).

If you are under mounting the tub, be sure that the fabricator has your tub specs. We did a drop-in tub. DS did under mount. She can’t lean her head back because the edge of the tub deck pokes her in the back of the head. My friend is about to do an under mount and her fabricator told her he can do the reveal in a way that she won’t have that problem. Be sure to talk to the fabricator about it.

Seamless takes a lot of angst out of the installation for the homeowner. You don't need to worry about how the seams will look, will they fail overtime, etc.

It can also be a less expensive installation. Easier to transport, easier to get the pieces in to the room, and in a 3-wall alcove installation, for example, easier to get everything snug. A busy shop might even have the material on hand, and if color and pattern allow, it can be fabricated out of off cuts or remnants.

If you want a single piece, the fabricator usually has to procure a new slab. The entire slab, for the most part, is yours.

Structurally, each will perform well given the proper substrate.

It's a toss-up for you. The fabricator should be able to show you what to expect regarding the seams, his or her capabilities versus what the slab's color and pattern have to offer. Certainly ask if all of the pieces come from the same slab or sheet.

Then look at your bathroom. Lighting location, from the windows and light fixtures. Some lighting can highlight a seam. A 3-wall alcove might be tougher to fit than a 2-wall, etc. Design plans. Will you have something on the tub deck. If a seam goes wonky, will a candle, or a towel, or a planter cover it?

At the start, most everyone wants a single piece installation, I would as well. But once things are explained, homeowners usually realize that seamed installations can work just fine.

Thanks for the thoughts, Mongo. This install will be a 3-wall alcove, and the things most likely to be on the deck are cats (moving targets). I suspect the quote for the single piece will be significantly higher, in which case our decision will be made for us, so it's good to hear that a seamed installation isn't necessarily inferior!

We used the rest of (the middle) the slab for window sill, hutch ledge, shower curb, bottom of 2 niches, top of pony wall. So the middle of the slab wasn’t wasted.