Emilio R,The Property was a two story property, so it was approximately 800 sqft per floor, plus the square footage of the roof (The roof isn't flat).I understand that 10 x 10 = 1 square or (100 sqft), but what I did was took a measurement of the property width wise from the outside, and then guessed the length of each "side" or "roof plane" and then figured out the squares using that information.While I'd still like to figure out a more accurate way of measuring a roof without actually climbing on top of the property to measure it.

The result is usually shown as a dollar amount based on a square footage basis, so that a 1,200 sq ft home will be very close or at 20% more than another that is 1,000 sq ft.

Some companies that write builders risk may allow a rehab property to be insured if the home is to be substantionally improved in square footage or gutting to the studs.

I intend to finish the attic into a master suite, and add a non-conforming BR/office, LR and bathroom to the basement to more than double the finish sq footage of the home.

Have you looked at smaller square footage homes in the same development and run the numbers?

When you own a co-op, you actually own shares of a corporation that then lets you use a proportionate amount of square footage (your apartment) for living.  

I own a duplex zoned R-6 with a parcel square footage of 7973.5 on 0.183 acres.  

(Sold price is hidden on the screen, but they display square footage and price/sq ft, so....math.

After researching numerous properties, I found one with each unit having the same finished square footage as our current home, because I know my wife wouldn't be interested in downsizing.

Depending on the size, a small mini split can work as well.All in, in AZ, we are seeing a conversion like this cost $40-50K for roughly 600sf of additional / permitted square footage.