Why is this an unreachable build?

[Danni0617]

Any ideas? Also yes, I'm aware I have a lot going on that needs my attention lol

 

[SL33PW4LK]

The dupes do not hang on the stairs.

[SheepKing]

You have your atmosuit checkpoint set to vacancy only, have no atmosuit, and no power. Select the checkpoint and in bottom right change to always allow.

[SackMaggie]

You need 1 or 2 tiles above each stairs. (For the right side).

And the left one because the setting on atmo suit checkpoint(You can just disable it for now).

[PhailRaptor]

On the right, Dupes are 2 tiles tall.  They can hang on the Ladder, but they need a free tile above it to move across.

On the left, the Exosuit Dock is blocking access.  Either disable (or deconstruct) the Checkpoint, or give it power/air/a suit so Dupes can use it.

[Chipplyman]

[Removed] This post was based on speculation, and was incorrect. 

[brucemo]

People who are replying to you are making assumptions about which tile you are talking about, so maybe you could make that explicit.

If you are talking about the one with the triangle, there's no atmo suit in the room, dupes can't just walk through the checkpoint, and that probably has something to do with it, since the tile is reachable if it's possible for a dupe to path into that room.