I looked at a house last week (Corrales for the locals), that had a nice big main house, an art studio of lesser quality, a detached garage with horse stables and a tack room. The sticky part is a detached guest house that is set up as a doctor's office. One bedroom is the doctor's office, the other is an exam room complete with an exam table with stirrups. There is no kitchen, it is used as a file storage area. Good construction, would make a nice little guest house. Since it is used as a commercial space, can I or should I try to value it as part of a residential refi appraisal. Zoning allows for a home based business as long as the space is 1,000 sf or less. This space is closer to 1500. Thinking of addressing it as an accessory unit with no kitchen and let the UW deal with the commercial use of the property.