Floor Area of your property

The term floor area has a legal definition as per the New Zealand building code.

“floor area, in relation to a building, means the floor area (expressed in square metres) of all interior spaces used for activities normally associated with domestic living”

This is in harmony with how calculations of “floor area” are on architectural drawings for building work. Commonly information from building plans is used when insurance is arranged. Floor Area is the term used in insurance contracts.

If you have legal plans of your property, (available from Council) you can rely on those figures.

Houses are insured on “Floor Area” not to be confused with area of house. Check your policy.
Having a 100m2 groundfloor and 10m2 room in roof cavity does not require insurance of 230m2 “Floor Area”. 
But 110m2 as per building plans.
House area is something that has appeared after the earthquakes. Check out the ANZ site here, second reference is to the building plans that is the correct one.
Then they offer you a guide to measure the outside.
What is the purpose of a Code of Conduct if they practice in this way.


  1. When pricing a house to build, it is usually an aerial footprint taken to give you a guestimated building / m2 price as there are many building elements required within eaves, (which of course are outside the floor area). We also need to remember to include exterior a7 Interioer wall thicknesses, which can vary depending on the age / constructuin style of the building.

  2. My mother moved to Tower in 2011. Her house insurance premiums rose dramaticaly to be about $1500 for this 2014 year. On checking this year and previous years (2012, 2013) it appears they have calculated the premium on the basis of a floor area of 340sqm! She is one of two joined units and I suspect the 340 is the total of the two. So they have been overcharging and we are trying to get the overpaid premiums back. They suggest that it would have been my mother who told them 340sqm. Most unlikely – how would she know? Tower say they do not have access to data concerning the size of the dwelling. Do they? Who does? They acknowledge the overcharging and also state they would never have rebuilt a house that size even if was insured for that size but are trying to avoid repaying the overcharged premiums. Very interesting.

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