We had a contractor build 2 walls and an office space in our building which we rent.  For Tax purposes, should I capitalize these expenses, expense them in the year done/paid, depreciate them?  I realize these are improvements to the space, but because we rent the space, I don't show the building on my balance sheet.  I believe it should be taken over the course of several years, but how to go about doing this?  Form 4562 as amortization costs for start up? These costs were incurred during the 2nd year of my business.