Can't Build On Highway - Help Needed (Creation Kit)

[WhoppingTurd]

I've created a custom settlement/base area on an elevated highway next to Outpost Zimonja. Building and the workshop works, however I can't build anything on the top level, like I'd be able to at the Graygarden settlement of the same type. Is there some way I can add a "ground level" as such so I can build on the top road?

I've also cleared some rubble and debris piles within the creation kit to give the area a cleaner look. Would this impact the building function?

The red outline stays no matter how far up/down/left/right

Edited December 1, 2017 by WhoppingTurd

[Ragoda]

It seems you need to have that area either Navmeshed, or just simply place hidden floors below the ones which don't allow placing.

Pain in the posterior both but I prefer adding hidden floors myself.

[chucksteel]

You need to add the WorkshopStackable (something) Keyword to all of the highway tiles. You can't build on them without the proper keyword. Don't edit the vanilla form or you'll edit all of them in the game. Duplicate the forms and add the keyword. set the original ones to "Initially disabled" and replace with your new versions.