https://ttlc.intuit.com/community/investments-and-rental-properties/discussion/is-schedule-e-or-c-us...

If real property you would put it on 1040 schedule E. not subject to se tax

If it provides "services", yes, self employment tax applies and it goes on Schedule C.

If "services" are not provided, it goes on Schedule E.

From what I remember from court cases, I think I came to the conclusion that most self-storage facilities do NOT provide "services".

If you read the instructions for schedule E, line one says as an example "self storage unit" so I can see why the court cases would side with schedule E, therefore no SE tax