What are some examples of some horror books set in a single building? I’m interested in things like a mall, theater, skyscraper, or maybe a large mansion, but not an ordinary house. I’m also not interested in any books with “snow globe” style plots twists. Thank you for any recommendations 
High-Rise by J.G. Ballard.
Hell House by Richard Matheson is a classic.
The Haunting of Hill House, by Shirley Jackson. I read it outside on a bright, clear day, and was still creeped out so bad, for days, everything looked sinister. If a stranger smiled at me, I was sure they were Jack the Ripper.
Freaking scariest thing ever. She has another book called We Have Always Lived in the Castle, that I have thought about reading many times, but I’ve never quite felt safe enough.
Psycho by Robert Bloch.
The Shining?
The bolded is more a psychological study than horror, so you can read with no fear. 
More Stephen King:
Misery
Gerald’s Game
The novella (and presumably the graphic novel based on it) Trapped by Dean Koontz takes place almost entirely in a house and its yard. There’s also his novel, The Face, that takes place in the main character’s employer’s home.
Another that takes place in one “house” is The Thief of Always by Clive Barker.
And lastly, though it’s not my favorite, House of Leaves by Mark Z. Danielewski does as well, but it’s another story set in a “house” rather than a normal house.
nm.
J.B. Priestley’s Benighted, filmed in 1932 (with Boris Karloff, Ernest Thesiger, and the chick who played Old Rose in Titanic) as The Old Dark House.
Aren’t those just in ordinary houses?
Kings short story “Toys”
Horrorstörby Grady Hendrix** **
Richard Bachman’s Rage. Set in a classroom
The Relic. Set in a museum. Really pretty good.
There’s Nyctophobia by Christopher Fowler, which is set in ‘a grand old home in southern Spain’, so i think it probably qualifies as a mansion.
Or maybe Five Stories High which consists of 5 novellas by different authors, all set in the same building, Ironwood Lodge, with a connecting narrative between the stories to tie it together. The editor and author of the links is Jonathan Oliver and the novella writers are Nina Allan, K.J. Parker, Tade Thompson, Roberet Shearman & Sarah Lotz.
Bentley Little also has several which qualify, I think: The Store, The Resort, The University, aka The Night School (may be multiple buildings), The Academy, probably others. There’s one set on a farm and one mainly in a church, iirc.
The Manitou - Graham Masterton
The Well - Jack Cady
The Keep - F. Paul Wilson
Origin - J.A. Konrath
The Devil in Silver - Victor LaValle
14 - Peter Clines
The Exorcist ?
The Green Mile - Stephen King ?
The Amityville Horror
I’m pretty sure James Herbert has one or two horror novels that take place in a single building.
Also maybe these?
Into the Drowning Deep - Mira Grant (not a building, but a massive research ship)
The Unit - Ninni Holmqvist (not exactly horror, but pretty horrible)
The Ruins - Scott Smith (not a building, but ancient ruins)
The Turn of the Screw is set in a mansion, and is brilliant.
Set in a mysterious apartment block in Los Angeles with many dark secrets. Reminiscent of Lovecraft.