depreciation is calculated by taking the construction cost of the building (not the pruchase price, unless you are building it new) and dividing it over the deemed useful life of the building. A quantity surveyor can assist by determining the historical construction cost of an existing building, and providing a depreciation schedule.
Blaze if the property was built before 1987 then you will not be able to claim the building depreceation, QS can i think depreciate things like existing Air Conditioners, Hot Water systems, (Fixtures and Fittings) but if its under a certain combined value then its not worth getting a QS out. Please correct me if i'm wrong guys
My understanding is that the ATO can reject your claim if it can't be substantiated. Unless you really know what you are doing I wouldn't risk doing it yourself. Some of the companies have a policy that if they look at the property and you can't claim at least the cost of the report in the first year they won't proceed ie they won't go ahead if its not worth it for you.
We have been amazed at the amounts we have been able to claim on older properties where we almost didn't bother having one done. Of course, for a new property it should always be done. Its also not as simple as using the whole construction cost as capital works because some components are classed as fixtures and fittings as opposed to building, and some costs of construction can't be depreciated. It's a specialist field.