Unheated or unfinished portions should not be included in the square footage fields, but should be stated in the comments section. Square footage should only comprise areas with a minimum ceiling height of 5 feet (1.5 story or A-frame houses, for instance). Areas such as attics, storage rooms, and other non-living spaces should not be included in the calculation. The reasoning is that these are not useful living spaces so they shouldn't be counted as part of your home's square footage. However, you should note these areas in the comments section so that when the building inspector arrives to measure your house he knows not to include them in his calculations. For example, if your home has 8500 square feet of living space and no one lives there now, then you're over your city's limit. Even though nothing usable exists in some of those rooms they still need to be included in your calculation because you want to be aware of this before you build anything more than skin deep in any of those areas. In most cities the requirement is set at 2% of total living space per unit. So if your town requires that you include 10% of the value of your home in its assessment, then you would multiply 8000 by 0.2 which equals 16000.