I'm talking like big square footage in desirable locations that isn't just in the Big Pink.

My questions would be what is the sq. footage, does it have a garage, central air, any other features and how updated will it be..?   

Some of the issues include light & air requirements, minimum head height, minimum room square footage, minimum glazing square footage to name a few. 

Is it as simple as 1/5 or does it go by square footage?

Adding a closet will probably not make much different in the appraised value since you are not adding sq footage.

Although I love the home, I'm finding that we are in need of more square footage and land for my growing kids.

Mostly, the owner of the property on either side of the parcel would buy it at a low cost to include footage to their own property.

No deal to investor = no representation from me@Joel Owens The square footage of the property is 7020 and it is a pretty big building.

You offer what you feel the property is worth based on similar size (beds and baths and interior square footage)/style/condition homes in the area.

If you can add an easy room (study, den, patio, etc), add easy square footage, or get a property that needs sweat equity, this allows your to continue taking the new earned equity out, and redeploying it for future investments.