In 2009, BOMA International published "The Gross Areas of a Building: Methods of Measurement". The document is primarily concerned with the appraisal, valuation, replacement, and construction costing for buildings of all types. Using the standard, any building can be measured, including office, retail, industrial, residential and institutional buildings. The standard outlines two distinct measurement methodologies, called "Exterior Gross Area" and "Construction Gross Area".
This method is similar to the BOMA 1996 Gross Building Area (which has been removed from the 2010 and 2017 office standards). Exterior Gross Area is determined by measuring to the outside surface of exterior walls for each floor without deduction. It includes enclosed structured parking but excludes the roof level of a parking structure. Exterior Gross Area is most often used for tax assessment, but it may also be used when leasing an entire building to a single tenant, so long as both parties agree.
This method includes all of the areas measured in the Exterior Gross Area method but also includes unenclosed areas within the building perimeter that has a structural floor, or are covered by a roof or canopy. This method is useful for determining construction and replacement costs of a building.
In 2018, BOMA International released the "BOMA 2018 Gross Areas Standard Methods of Measurement – ANSI/BOMA Z65.3-2018" standard. This new Gross Areas Measurement Standard (sometimes referred to as "GRAMS"), is a completely rewritten document from its predecessor and is much more comprehensive compared to its predecessor. This latest version of the BOMA Gross Areas Standard follows the BOMA 2017 Office Standard in its progressive formatting, text and illustrations.
This latest version of the Gross Areas Standard removes the Exterior Gross Area (EGA) and Construction Gross Area (CGA) designations in favor of four distinct measurement methods, known as Gross Area 1 (Leasing Method), Gross Area 2 (International Comparison Method), Gross Area 3 (Volumetric Method), and Gross Area 4 (Construction Method). The ability to properly apply one or more of the Gross Area methods is dependent on the inclusion or exclusion of certain Space Classifications (A through F). Each Space Classification comprises specific and various architectural features that a building may have. Determining which Gross Area methods can be calculated is dependent on the architectural features, and consequently the Space Classifications that have been included in the measurement.
The purpose of the four methods is to provide the real estate industry with distinct datasets that are uniquely designed to accommodate the various needs of the industry with regards to Gross Area measurements. Gross Area 1 is primarily meant for single tenant leasing in buildings. It is similar to the Exterior Gross Area in the 2009 Gross Areas standard, except it now includes Balconies, Exclusive Use Covered Galleries and Finished Rooftop Terraces, in order to align more closely with the BOMA 2017 Office Standard and its inclusion of these areas for leasing. Gross Area 2 aligns with the International Property Measurement Standards (IPMS), which is meant to provide a consistent method of measurement for building transactions and valuations across international markets. Gross Area 3 is used as a basis for environmental studies, with its most distinctive architectural inclusion being Building Voids. Gross Area 4 is primarily designed to be used for estimating the full value of a building and replacement costs. It is similar to the Construction Gross Area (CGA) found in the previous Gross Areas Standard.
The latest 2018 Gross Areas Standard includes many other important features, but it is especially thorough with regards to single occupant leasing, which is arguably the most prevalent use of the standard. Notably, single occupant leasing includes support for Multi-Building Sets using Inter-Building Area calculations to determine the proportionate allocation of areas such as Connectors, Auxiliary Structures and Parking Areas to buildings within a Multi-Building Set or Building Complex.
Extreme Measures is the editor and illustrator of the BOMA 2018 Gross Areas Standard.