Artist Ray O'Bannon has some free haunted houses (ships, aircraft, graveyards, fairground rides etc.) at his website complex:
http://ravensblight.com/papertoys.htmlHere is my build of his Ghost House:
It's just about big enough for 28mm. I might feel like trying it again at some stage. I believe the Bleak Estate is also big enough, but is so under-engineered that I wouldn't want to try it again.
The Cliff House is maybe large enough for 20-25mm, but not 28mm.
Most of the other buildings are for much smaller scales, mostly scales that don't suit horror because, well, they're tiny. Often 10mm, or microscale.