So... yeah.

“You can replace walls but only with different styles of walls, not types. So wood doorway for a brick doorway but not doorway to solid or window. Basically stripping away one of the major creative tools builders have. Back to boring boxes for everyone… Edit: Forgot to mention… same goes with roof tiles. So if you enjoy the floating roof tile trick where if you changed it to an angle roof, you’d be able to delete the wall under, yeah bye bye. That’s gone too. 2nd edit: Double walls still possible but it involves two half walls on each side and the flamethrower trick. Break both and place next set of double half walls facing opposite direction. 3rd edit: full brick walls can be flamethrower trapped and doubled…”

Content retrieved from: https://massivelyop.com/2020/08/05/fallout-76s-colossal-problem-patch-lives-up-to-its-name-as-the-communuty-melts-down-over-massive-building-bugs/.