I'm kind of curios what you actually changed nothing you say in the description actually points out the changes nor do the images. As far as I know vault 88 is massive once the quests are done, I'm talking possibly as big as Sanctuary. No area in Vault 88 seemed to have limits outside the build budget which will run out before you ever need more space unless modded.
I use only maybe 3 mods that would affect it one being build budget increase for (every) settlement the other 2 are scrap mods so maybe that allowed me to scrap things you could not though the biggest concrete I can think of you clear those using the DLC and pretty much part of one of the quests.
The image may not have been self-explanatory (I think that's what I understood), but all I did was to give a more rectangular appearance to the building area, pulling back columns and walls. And that's all I did. I did not move on the building boundary, nor in the other areas. And I also use mods that clean anything and that eliminate the build limit, so I preferred not to mess with it in the mod.
4 comments
I use only maybe 3 mods that would affect it one being build budget increase for (every) settlement the other 2 are scrap mods so maybe that allowed me to scrap things you could not though the biggest concrete I can think of you clear those using the DLC and pretty much part of one of the quests.