* Public record and the first 2 appraisals list the house as 2185 sq. ft.... third said was 2281, fourth said was 2529. No additional renovations have been made. --- Jo Ann offers sage advise overlay and doublecheck the 4 appraisal sketches . Perhaps the garage was included in the SF? Perhaps you converted the garage (illegal use in WeHo) or have a finished attic (older home) and the recent appraisers counted this as living area? Maybe you have an enclosed patio or breezeway that the appraisers counted as living area? A detached guest house or room/studio/office over garage? Maybe you have a 2 story house and the appraiser(s) estimated the 2nd story SF being the same as the 1st, and failed to subtract offsets, airspace, or balconies? Y
You may find that Appraisals 1, 2 and 3 have the most reasonable measurements. Something in report 4 should jump out and account for the discrepency.
* I am confused and the discrepency in sq. footage could equate to nearly $200,000. --- Homeowners and sellers have embraced the highly misleading habit of equating sales prices to a "$ per SF" factor. This is usually grossly irrelevant and creates the illusion 350 SF may be "worth" $500/SF or more. Refer to your appraisals and see how much the appraiser(s) adjusted "GLA" differences in their Sales Comparison grid. The appraiser's figures may differ, but should be derived from market data.
* IS THERE A DEFINITIVE REGULATION AND INDUSTRY STANDARD THAT MUST BE ABIDED BY TO MEASURE A DETACHED SINGLE FAMILY HOME IN CALIFORNIA? IF SO, WHAT IS IT? --- No universal, mandatory guideline in California, although for similar assignments I explain the standards, tools, and techniques used to obtain the measurements. The appraiser typically measures the outside of the dwelling, and subtracts "airspace" that lacks a floor on same level. Typically, stairs themselves are counted towards the second floor, and the usual closet or open space beneath counts as 1st floor area. Garages, enclosed patios, rooms over detached garages, balconies, rooms not accessible from inside the dwelling are typically NOT included as living area.
The first 3 square footages are reasonably close (<100SF, and may buyers not even blink at the difference). Simple sleuthing - maybe a few measurements - will reveal the cause of the more troubling 350 +/- SF difference. Or engage an appraiser to provide an additional set of measurements, as several have suggested.
More experienced forumites.... is there any issue with "her" appraiser (#3) consulting "her" regarding, or reviewing "his" appraisal #4 in these circumstances?
OptionsDave's questions/anxiety are mostly over the SF mystery, and perhaps "her" existing appraiser's review would exedite an understanding and release some stress, not withstanding Mr Evans excellent advise to back "your" appraisal (another one if neccesary) with a heavyweight appraiser having plenty of experience in court and with similar disputes.