Larian Studios Forums Divinity: Original Sin 2 - The Modding Dungeon Divinity - Original Sin 2 - Modding General Duplicate a set of walls (House)

So I managed to create the first floor of my house, but I want to create at least one more floor, how do I go on about doing that? I tried to find any way to duplicate the walls and stack it on top, but there is no duplicate option.