You really want to step over that every time getting in or out of your shower? Is the floor pitched properly for a zero entry shower (if not there is bound to be other issues)?

That seems like it would be a tripping hazzard. I’m picturing the shower curtain hanging over that and someone going to get out of the shower not realizing that small dam is there espeically since it is a guest bathroom.

They are soft/rubber so I was thinking less of a tripping hazard than a firm and taller shower curb…maybe not. I mainly liked the look of a shower curtain better than glass,. Maybe the answer is it doesn’t matter if it’s a shower curtain or glass, still need a few inches of a curb to keep the water in. This is not a curbless/sloped shower - we have a shower pan as didn’t want to tile the floor and have potential water issues from second floor baths above the kitchen.

" we have a shower pan "

Then why do you feel you need a dam? A long enough curtain should be fine with a curb.

Just getting alternate advice from designer and builder that curb/shower curtain combo won’t keep the water in the shower.

If you have a curb then water won't run out onto the floor and I would think as long as you had a shower curtain that hangs down past the curb inside the shower it should keep water spray from getting out of the shower just like a curtain on a shower/tub combo unit.

If the curb and shower curtain won't keep the water in the shower, then the entire design is completely suspect. It likely isn't large enough to even be usable.

And the Designer & Builder will not make money on a shower curtain..................................