But you can look at value ads, like for example I am looking at finishing the garage after I do the kitchen and adding a freestanding garage, which is popular in the area I am in so that will increase square footage.  

Anyway, I now have a bigger house and want to refi and am curious how the process goes for adding square footage.

I have heard it is 50/50 but have also seen that people are supposed to make the measurement of deductions based on square footage.  

By ensuring that the first house I sell is the one that will comp the highest (most square footage, most rooms, best finishes, etc), I have the opportunity to bring the value of the other properties up.

For instance, the square footage, any permits for recent improvements, land size, condition etc.

.) * The ARV (based on comps) is $290,000* The Zillow estimate (most likely incorrect because it's displaying less than half the actual square footage and too few bathrooms) is $258kBecause of the repairs that need to be done, the bank has told me I need a renovation loan, which would be an amount that is more than I can qualify for.

I don't go by their Zestimate I've been checking the comps of similiar square footage, bed/bath combo, and in the relative area.

Also, using a comp from 2007 is another major issue: 1) Its only 1 comp and 2) I wouldn't trust a comp that was more than 6 months old. 3) Make sure your comps are very similar to this property (ie. same # of bed/bath, similar sq footage, same style of home, etc).

Now I also take into account idiosyncrasies of the house and the neighboorhood, and whether the house is under or over built, but initially it comes from an average sold per square foot number from the area, multiplied by my square footage.

more details needed, square footage aprox, shape(square, rectangle, round) crawl or basement?