In fact, my trigonometry is a little rusty to say the least, but if we assume that the outer surface of the inner core is 5,800 kilometres deep, then you would need to own the freehold of circa 300million km� which is about two-thirds of the current land mass on the planet to be able to build a decent sized house � unless you had many storeys of course! Given the climate and temperate nature of the inner core though, it wouldn�t be a nice place to dwell.
This is just for fun, and no doubt a true mathematician will dispute and correct me.