How to make low walls?

[Kraker]

Hey, I'd like to make a building like this one in Mysilia on my lot. How do I achieve this low wall effect?

https://imgur.com/N9mans5

[ch]

If I remember correctly, you need to craft a Room plate, place it inside the building, middle click and switch "Atrium" to On.

[Kraker]

Oh, so it's in room sign, not house sign. Thanks for help.