Writing off space in a mixed-use building?

[Timothy L Olsen]

I couldn't find this question elsewhere, but it's likely been addressed.  I'm considering buying a mixed-use building with apartments upstairs and commercial space below.  I'd like to use a part of the commercial space for my property management office space.  Will I be able to write off the use of this space much like a home office or if I was renting commercial space from someone else?  Thanks for any insights!