Diggable dirt in barns?

Is it possible to set the ground in barns as diggable? The ground is dirt, but for some reason it can’t be dug for purposes of traps or fence posts or whatever.

The behavior is a bit strange as it won’t allow you to do things like pitch tents(like you can outside) or build beds(because I assume you can’t build beds on dirt), but you can (if I recall from my testing) build walls. I mean to try building a floor/roof to see if that works and changes building behavior (to build beds), but right now if you want to turn a barn into a shelter you are unusually limited in the kinds of building you can do. You are more or less stuck with cots and the rollmat.

Which is too bad, because being able to park your vehicle in your shelter is a huge benefit even if the walls aren’t very sturdy.

Any thoughts on this? I haven’t tried everything.