There are actually 2 buildings: the "Farm House" is the original home in the Bartlett Tract 1200 sqft; and the "Tree House" built after WWII, a legal(!) unit over the garage in the back 750 sqft. The building in back is 2 stories, with 2 bedrooms, and 1 bath. The main house is what's described in the rest of the listing.
This property is off market, which means it's not currently listed for sale or rent on Zillow. This may be different from what's available on other websites or public sources.

