The ANSI standards approved April 8, 1996 and endorsed by several entities to include the AIA, NAR, Fannie Mae, Freddie Mac, The Appraisal Foundation, Bureau of Census, ERC, NAHB and a host of others gives clear direction on how to calculate the Finished square footage of a single family residence, commonly referred to as GLA by appraisers and others.
As quoted: "A common construction practice is to provide a floor opening for stairs that is the same size as the stairs themselves. Therefore, the area of stairs included in finished square footage is typically equal to the area of the opening in the floor. For example, a two story 28-by-42 foot house embodies 1,176 finished square feet on the first level and 1,176 finished square feet on the second level, provided that all areas are finished and the opening in the floor on the second level does not exceed the area of the stair treads. .....In addition, areas beneath stairs are included in the finished square footage regardless of the distance between the stairs and the floor below or of the degree of finish of the area." Hard to question this standard in court when it has been adopted by so many agencies. The entire standard must be adopted when measuring--the appraiser does not have the luxury of picking only certain standards when benefit any cause. Have you had problems with homeowners, realtors, investors, etc. when defending your measurements? If so, take a course on ANSI and uphold this document as your protocol in measuring sf dwellings. Call the NAIFA to set up a course in your area, 314-781-6688, ask for the ANSI course.
An appraiser may choose not to adhere to these standards, but then again it is that appriser who must defend their own work.
Monica L. Trotter