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  • Irina Tikhomirova

Measuring Methodologies Explained: Differences among Total Scanned Area, GIA and GLA


There are different methodologies that exist to measure the area of your property:


Gross Internal Area (GIA)


Gross Internal Area (GIA) is the area of a building measured to the internal face of the perimeter walls at each floor level. It includes the internal walls' thickness and most finished areas. It does not include areas like garages or unfinished basements, exterior walls, terraces, balconies, decks, patios, porches, conservatories, and other non-internal areas. GIA is used in real estate photography and real estate agents when determining the size of a property to be sold.


Total scanned area


Total scanned area includes all scanned areas, like porches and balconies. This number is most useful in determining the overall size of your floor plan for pricing. It is calculated by measuring the outside perimeter of the structure and includes all finished, habitable, above-ground areas. Total scanned area is different from GIA and GLA, as it includes all scanned areas and not just the interior walls and livable spaces.


Gross living area (GLA)


The gross living area (GLA) of a home refers to its above-grade, finished living space—what's also commonly referred to as its square footage. It is determined by including everything within the exterior walls of a home and subtracting the space taken up by walls, stairwells, and other non-livable spaces. GIA includes most finished areas, but not areas like garages or unfinished basements. Exterior walls are also not included in this calculation.


There are generally 3 main criteria for what makes interior space count as living area. Firstly, the space has to be heated. The heat source has to be a conventional heating system, such as forced air systems, solar, radiant and ductless systems. The second criteria is that the space has to be finished. The area must contain walls, floors and ceilings of materials generally accepted for interior construction (painted drywall, carpet etc.) The ceiling height of the finished space must be 7 feet. In finished attic spaces or rooms with sloped ceilings we include the portion of the room where the ceiling height is at least 5ft. Finally, the finished area must be directly accessible from other living area. Typically this access means a door, heated hallway or stairway.


GLA aligns with the ANSI Z765-2021 standard and is one of the most frequently adjusted features in the sales comparison approach of an appraisal and is used to help determine what taxes are owed to the local assessor, as well as help an insurance company know what to expect for replacement costs.


If you purchase OpalAi’s Appraisal Home Report, you will receive a detailed Gross Living Area calculation of your home aligned to the ANSI Z765 standard. This report will include the entire exterior perimeter of the structure and all finished, habitable, above-ground areas. The report will also include:

· Fixed furniture, windows, doorways displayed on the floor plan

· Interior and exterior measurements

· Ceiling height

· Labels for each room


OpalAi’s Appraisal Home Report is a fast, accurate, and cost-effective way to measure the Gross Living Area of your home with your phone. Try it now for FREE!

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