Why does the exterior trim keep coming inside?

Okay, so I figure it out.. I just have to make part of a half wall- like not connect it to any other walls and then pull the piece and connect it.

Also if you're trying to figure out how to stop the outer trim from coming inside... first delete all of the outer trim, use the room tool and trace all the rooms with it (it's kind of annoying because you'll have to paint the walls again).. but after that put the outer trim/friezes back on and then if you need to place fences or half walls you can do it by placing one piece and drag it to connect to wall.. this will prevent the trim/friezes from coming inside.

Thank you for the tip!

Maybe it's cold?

It's still not working for me. As soon as I take the floor out on the second floor of my entryway, here comes that stupid trim. I've gone over and over it to convince it that it's a separate room, but it doesn't believe me.