How to signal 'do not disturb' without a door
Use headphones, a small desk sign, a lamp color, or a shared status message. Define what it means: text first, no casual conversation, or only interrupt for emergencies. Agree how long the signal can stay on.
Give a clear “available again” signal so roommates do not feel frozen out. Use the system for calls, focused work, and sleep—not as a permanent wall.
A simple signal works because it removes guessing, not because it creates silence.