How do I deduct renovation expenses on an un-rented apartment?

[tanya6884]

I purchased a duplex as an investment/rental in 2015. I live in the upstairs apartment and plan on renting out the downstairs apartment.  I spent all of 2016 renovating the downstairs apt. how should I deduct these expenses if I plan on renting out the downstairs apt. in 2017 (when the renovation will be complete)?

[MinhT]

Expenses incurred prior to the unit being put on the rental market are not deductible. Renovation costs are added to the cost basis of the unit.

[tanya6884]

So I can only take into account these expenses whenever I sell the duplex?