Hi I have a spare car park for rent in my owner occupied apartment building's secured car park. Obviously because it is a secured car park, the only market pool would be the apartment's residents and this cannot be changed. Because the market pool is limited, I envision it may be awhile before I can find anyone who would rent the car park space. The suburb does have a many on street parking available. Still, I intend on renting out the car park as it is surplus to my needs. Question is, if the space remains un-rented for prolonged periods of time, even if I continuously advertise for rent, is my mortgage interest deductible over the periods when it is not successfully rented out? Technically it would seem so, as it would be the same as having a spare bedroom to rent whether or not it is successfully rented out. But because it is a car park, in the above circumstance of perhaps prolonged periods of vacancy in which an owner could potentially personally utilise and yet claim tax deductibility, would it make it a difference to the tax office's view of it? Curious... any thoughts welcome. Thanking you in advance all you experts on this forum. PS: I do realise it will later on attract capital gains tax on the same proportion of it.