Yes it is possible.

You may want to provide photos,comstruction details.

Here's a photo.

Be careful that the new floor isn't slippery. The reason small tiles are used in shower floors is to provide slip resistance.

what kind of solid floor?

Like a completely enclosed shower pan?

Or new tiles that are larger?

What's wrong w/the floor that's there now?

the issue is, tearing out the old tile and maintain waterproofing/not damaging the underlying surface. I don't see how you plan on doing that w/the bench and the wall tiles.

plus, the shower floor should have a slope. Not sure if you're doing a pan if you would maintain that slope.

You aren't giving us enough info. don't know how the current shower was constructed, and don't know what you want to switch to.

There are many options --I'm leaning toward a Kohler cast iron. There are many options out there that of course take into account sloping etc. I'm tired of cleaning grout that never stays clean. Plus I made the mistake to choose marble basketweave tile so I'm limited what I can use to clean it. The picture I posted was right after the bathoom was completed 9 years ago. The walls are still in great shape but the floor is not.

The odds of finding a premade/ stock shower pan of the precise size to be able to integrate into the wall waterproofing are very very small. And drain placement is an issue.

If there are no stock solutions, getting a custom made solid surface (Corian) shower pan is an option.

Yes I was also looking into Corian (and there are other materials out there) -- that do custom made shower pans. I guess my question -- is it possible to just put in a new shower pan without taking out any of the wall tiles?

You replace the floor, you replace it all. Walls too. Otherwise the waterproofing is compromised.

How would the new shower pan fit under the current curb, bench and bottom row of tile? Shouldn't the curb be one piece of material instead of tile anyway and not made of tiles?

Wow! Have not heard of this option. The marble is in great shape, it’s just the grout and I didn’t want to redo the grout (did that a few years ago) and have the problem come back. I will look into epoxy grout! Thanks!

Be sure to check that it can be used with marble, I have it in 2 showers and a bathroom floor but the tile is all porcelain.

Seems like a 4 x4 foot pan, so not really huge. Try 1 part hydrogen peroxide to 2 parts baking soda, let it sit a bit, then use a soft scrub brush, every single week : )

Epoxy grout is safe for natural stone, but your marble should be sealed again, first. Epoxy grouts can take a week to a month to fully cure.