[QUESTION] Can't add new wing after I already have a 5 story main hospital - can't build walls after 1st floor

I've built a 5 floor hospital and have room left on the map to build another auxiliary wing which I am unable to build. I tried building a foundation on the ground level and I can put walls up but I can't build on any other floor above the ground floor.

I have the following installed: Doctor Mode DLC, Hospital Services DLC, More Staff, Pictures, More Names.

Hi, thanks for the message and welcome to the forum!

While it might not be completely intuitive, using the foundations tool on the above-the-ground should be what you're looking for, basically you can use it to mark which parts of the floor are part of the building, while the rest is considered to be part of the roof (so you can't build walls there).

Let us know if this helped!

Yes! Thank you. I could have sworn I tried that but I might have been viewing something other than the floor I was trying to build.