In a session today we were camped out in a Leomund's Tiny Hut and the DM determined that since it is described as a dome, the bad guys (Wraiths, so they are incorporeal) could enter the area from below. I went with it and it was a fun encounter, but I wondered what other people think about it. I can see two arguments.
His argument: It is described as a dome. So only the semi-spherical outside prevents things from happening. A dome doesn't (necessarily) have a floor, they can enter no problem.
My argument The intent of the spell seems to be to prevent baddies from coming in. And the rest of the wording simply talks about the "area", not a barrier.
Has anyone thought this through or seen a ruling anywhere?
Note: Given that I'm playing a 3 foot tall gnome, we decided that on subsequent castings I'd do two. One is the normal one and the other is an inverted on with a "floor" about five feet in the air, that extends into the earth. The overlap allows for protection.