Ok, lets start with the difference between GLA and square footage. Fannie Mae/HUD states that any room below grade is basement and is not considered in the GLA (Gross Living Area), so if you have a ranch or rambler with 1,000 sf of GLA and a 1,000 sf basement you do not have 2,000 sf of GLA. You have a 1 story home with 1,000 sf of GLA and 1,000 sf of basement. All rooms are counted but some are not give any value. Lets say you have a 3 bedroom rambler that has a 1000 sf of GLA and your neighbor has the same house that has a 1000 sf of GLA and has 4 bedrooms the value is the same. because the difference is reflected in the GLA adjustment. Room count does not really mean a hole lot. It would be like taking a 1000 sf basement and framing it off with 6 bedrooms, you added NO value. The average family would rather have a family room and a den. Basements range in a wide range of construction, from unfinished to finished the same as the GLA area. The adjustments for basements would range from $5 sf to $30 sf, depending on the quality of construction compared to $30 sf to $50 sf for GLA. GLA is defined as above ground heated living area with at least 6.5 feet head room. Any portion of finished attic area without 6.5 feet head room is excluded from GLA. Stairwells are included in the ground level GLA only and excluded from any second floor area (a stairwell cannot exist on both levels) or basement area. Unheated areas, even if finished out, are excluded from GLA except for supporting areas such as closets, halls, foyers, etc. Some areas, such as sunrooms, enclosed porches, etc., even when heated may not be included in GLA unless the finish is equal to the primary GLA; such additional areas are treated separately in the grid on page 2 as amenities when not included in the GLA. If a garage conversion to living area is above grade, completely finished-out to an acceptable professional level, and heated, it is included in the GLA, but a percentage adjustment may be made if necessary for differences in relative quality of the finish compared with the primary GLA. For example, the primary GLA might have 2 X 6 exterior walls with extra insulation and a crawl space with floor insulation, while the garage conversion might have 2 X 4 walls with more limited insulation and a slab foundation. When major differences exist between the quality of finish, the garage conversion is omitted from the GLA and treated as an amenity at the bottom of the grid. In some cases, a garage conversion may contribute less value than the lost value of not having covered parking, when the conversion is of poor quality.
I'm not trying to be rude but this really bothers me, that you are reviewing my appraisals and have no clue what you are doing. Now I see why I get a bunch of nonsense request from underwriters, that just wast my time.