Calculating house size, whats included

When calculating house size, what is the current accepted practice for including verandahs, patios, balconies, alfresco areas etc.
I'm talking mainly about when looking at project and custom house plans. What are the rules, if they exist.

For example, when thinking about our own house, it has a large elevated verandah at the front which has a concrete and pebblecrete floor, and no roof above it (typical 1960s house with garage underneath). At the back there is a patio area which has a pergola type roof with suntuff roofing. Should either of these be in included in house size ?

I'm trying to compare house plans, and to compare against our own home to see just how much space they offer and how much we are used to.

cheers
Arron

We have been house hunting lately and the figures quoted by real estate agents include everything that even remotely can be said to belong to the house.

They basically go in to NearMap, draw a perimeter line around the gutters and NearMap gives them a sq mtr figure. This includes eaves, all internal and external walls, porches verandahs, pergolas you name it.

One good example was a house quoted as 300 sqm (33 sq) that was only 22 sq when you added up all the rooms in the house!

Industry standard as follows:

Living areas (all habitable rooms) ~ taken as external of walls, not internal room size (this also applies to BASIX calculations)
Verandahs, patios, alfresco (usually combined)
Garage (single or double)

Then all these are totaled as a whole.

ALWAYS ask for a breakdown of areas as listed above

Here the bank will calculate square footage based upon the exterior of the wall measurements and SUBTRACT the space taken up by an attached garage or utility room (Water heater, furnace, storage area). I would assume that the banks there would do the same. Probably the best thing to do would be to ask the loan officer at the local bank as to how they make the calculation.