Hi @TheNefarious and @6b3de60ad83425ac
There have been some changes done to this.
Since you can do them individually now. Select the room and there should be an arrow to lower/raise
How do I find this slider for the foundation?
@Bombshell1985 On the main floor of the building click on the side of a room in the building that you want to adjust the foundation on and there will be a translucent plumbob with up and down pointed ends in the middle of the room. Please drag that plumbob up or down and the room and all of the building that is attached to it will move up or down. If you have more than one building on that main/ground level that is separated by one or more squares it will not move with the other building(s) - each moves independently. All rooms that are attached to each other are considered the same building and they will move together.
If you still have issues please let me know or send a further description and preferably a screenshot. Please let us know how it goes!
