If this is your personal residence with a basement appt you cannot deduct anything until the apt is rentable and you have it listed for rent. Until that happens all you have is improvement costs that add to the basis of the home for depreciation purposes when you start reporting the rental on the Sch E.
If you have a mortgage on the property it is ALL considered personal until the rental is up and running ... so until then enter it all on the Sch A.
