I currently own a brand new, just built in 2016, two story home in Maryland that has a Family Room and Open Foyer with Cathedral Ceilings. Basicaly, 500 square feet of "Open Space". There is no living space above my family room or open foyer. The ceiling height is aproximately 20'. The appraisal that was completed for the purchase of my home calculated the square footage of our home at 2,750. The sales contract from the builder was 2,690. Basically, the same figures. The local tax assement office came in at 3,243 or basically 500 more square feet then two other sources. It turns out, we are taxed in MD based on living space. Basically, the tax office measures the outside of the house and multiplies it by 2 for the 2nd floor. I discovered the ANSI Standards DO NOT count the "Open Space", such as "the area above" as such a room with catherdral ceilings. ANSI removes any squarefootage of areas with open space from the total living space figures. I am trying to determine if the USPAP calculated living space, in particular, homes with cathedrial ceilings or "Open Space" the same way as ANSI or is Open Space included in the total living space final figure. It just appears that in Maryland the tax office is way out of bounds as in comparision with national best practices and standards I have come accross when it comes to the proper measurements of a home. Thanks for any answers someone can provide.