BOMA GROSS AREA STANDARD 2009

A horizontal extension of an adjacent floor outside the exterior enclosure of a building that is not a roof, roof terrace, plaza or deck. 

A floor of a building that has an elevation below that of the average adjacent grade plane by a distance of more than two thirds of the vertical dimension between the elevation of that floor level and the elevation of the floor immediately above it.

A contiguous and undivided shelter comprising a partially or totally enclosed space, erected by means of a planned process of forming and combining materials.

A horizontal line forming a perimeter that encompasses all the constructed elements of a given floor of a building and other areas covered by a roof or a floor above. Nonstructural protrusions, including eaves, cornices, canopies, awnings, sills, ledges, casing, wainscoting, gutters, downspouts, signs, shutters, attached electrical or mechanical systems or decorative projections, are ignored.

A line connecting points that are equidistant between both base-building finished surfaces of a wall, not taking into account special finishes for adjacent occupants or furring or chases to accommodate pipes, wiring or equipment that serve adjacent occupants.

A covered or enclosed bridge, walkway, tunnel or other similar connecting element between two separate buildings.

The larger measure of the two gross areas, it includes the area defined as exterior gross area as well as other areas that have a structural floor, or are covered by a roof or canopy, that are typically unenclosed but within the building perimeter. It may be an appropriate measure of area upon which to base an estimated construction cost or for valuation using the replacement value approach of appraisal. Accurate construction cost estimating and replacement cost valuation should consider fully enclosed and finished space differently than unenclosed space, applying unit costs appropriate to various types of space.

The total of all the horizontal floor areas (as viewed on a floor plan) of all floors of a building contained within their building perimeters excluding voids (except for occupant voids), interstitial space, roofs, unexcavated areas, crawl spaces, un-structured on-grade parking and other site improvements. Make no deductions for columns or any structural elements within the building perimeter.

An unenclosed floor surface contiguous to a building that is suitable for use by an occupant and supported above the ground on at least two opposing sides by an adjacent structure, and/or posts, piers or other independent supports.

A line on the ground, a plaza, roof terrace or balcony in the same vertical plane as the outside edge of a roof or overhang that occurs at the level of the floor or roof of a floor level immediately above.

To separate the inside of a building from the outside, affording protection from the elements appropriate to the occupancy and the local climate.

The wall, roof or soffit that constitutes the envelope necessary to enclose a building.

The total of all the enclosed floor areas (as viewed on a floor plan) of all floors of a building contained within their measure lines, excluding voids (with the exception of occupant voids), interstitial space, unexcavated space and crawl space. No deductions are recognized for columns or any structural elements within the measure line.

Unenclosed pedestrian circulation providing the minimum path for access to tenant suites, egress stairs, elevators, refuge areas, toilets, and building entrances, and required by local building code to meet egress requirements, only when there are no fully enclosed pedestrian corridors serving a floor or portion (such as a wing) thereof. 

A normally horizontal, load-bearing structure constituting the bottom level of each story in a building including its associated permanent mezzanine, if any exists.

It includes the area defined as BOMA's "exterior gross area" as well as other areas that have a structural floor, or are covered by a roof or canopy, that are typically unenclosed but within the building perimeter. It may be an appropriate measure of area upon which to base an estimated construction cost or for valuation using the replacement value approach of appraisal. Accurate construction cost estimating and replacement cost valuation should consider fully enclosed and finished space differently than unenclosed space, applying unit costs appropriate to various types of space.

The total floor area contained within the measure line (generally, the outside surface of the exterior enclosure of a building) including structured parking. Typically, unenclosed areas are excluded except for external circulation and the top level of a parking structure. It may be an appropriate measure of area for use in planning and design of buildings with respect to zoning floor area ratios (FAR ), for real estate tax assessment purposes for some occupancies, for valuation using income or comparable value approaches, or for determining a lease rate when a building is leased to a single tenant.

The area of load bearing surfaces located above or below occupied building floors that is not available for general occupancy often due to inadequate clear headroom or lack of provisions for egress, and containing building structure or services predominantly serving adjacent floors or to provide access to such systems.

The ability of a generally horizontal structure to support live loads imposed by occupants plus static loads imposed by furniture, equipment, machinery, partitions and the like on a surface designed for occupancy.

Major Vertical Penetrations have a functional purpose, such as allowing passage of building services (HVAC ducts, flues, chutes, dumb-waiters, plumbing or electrical, etc.), or building access and egress,(stairs, escalators, and elevators, etc.) whereas voids only accommodate the need for certain spaces to be higher than adjacent floors.

A horizontal line on the outermost structural or architectural surface of the exterior face of the exterior enclosure, or at the exterior edge of any external circulation, of a given floor of a building. In determining the measure line, do not consider overhangs, pilasters, columns, awnings, eaves, cornices, sills, ledges, casing, wainscoting, gutters, downspouts, chimneys, signs, shutters, attached electrical or mechanical systems, decorative projections and the like that protrude beyond such surface or edge.

An intermediate horizontal load bearing structure that is between a floor level and the floor level or roof immediately above. The area of a mezzanine is often constrained by statute to a fraction (usually 1/3) of the area of the floor below. Mezzanines exceeding that fraction constitute full floors. There are three types of mezzanines that are measured as follows: Temporary Mezzanines are non-permanent (built with the intention of being removed or relocated), often tenant improvements, are supported upon the floor but otherwise not part of building structure, and used most frequently (but not exclusively) in retail and industrial occupancy for storage of goods and materials or as part of manufacturing processes. Such mezzanines are not measured as part of exterior gross area or drip line area of a floor or building. Permanent Mezzanines are not built with the intention of being removed and share building systems (HVAC, lighting, power, etc.). In a multi-story building containing elevators, the existence of an elevator stop at a mezzanine indicates that it is permanent. Such mezzanines are always measured as part of exterior gross area or drip line area of the floor immediately below. Unclassified Mezzanines cannot be classified as either temporary or permanent, are included in exterior gross area or drip line area, but are always disclosed when presenting area measurements.

A floor opening between two or more adjacent floors created by removal of floor area by or for the occupant that would otherwise be included in the exterior gross area or construction gross area of the floor.

Suitable for occupancy by people by virtue of a load bearing floor, building systems, required egress and, if applicable, a Certificate of Occupancy by local authorities having jurisdiction.

An upper floor or roof of a building that extends, protrudes, or is cantilevered above an unenclosed area below.

An enclosed, structured floor area used for transient storage of motor vehicles, including associated circulation and building services (such as exhaust fans and ducts that serve the parking area), but not including loading docks, sally ports and building service areas, such as enclosed auxiliary lobbies used to enter a building from parking areas.

Enclosed floor area located on the roof level of a building that occupies less than the total area of the roof.

An unenclosed horizontal load bearing floor surface intended for use and located at or near ground level, which constitutes the roof of space below it that is included in construction gross area.

The legal boundary of a parcel of land.

Space that has a clear ceiling height of less than 7’-0” (approximately 213 cm)

Space that does not meet the requirement of the International Building Code section 1208.2 Minimum Ceiling Heights, including subsections thereof. 

A permanent exterior enclosure oriented more than 15° from vertical with its exterior side oriented upward that encloses the interior of the building below it, affording protection from the elements appropriate to the occupancy and the local climate. 

An unenclosed horizontal roof (other than a plaza), or portion thereof, with a load bearing surface intended for use by occupants along with other appropriate and required features such as railings. 

Sub-grade space that is enclosed and contiguous to a basement that extends below the adjacent ground plane past the property line, often under a public right-of-way, such as a sidewalk or alley. 

Absence of a floor within the exterior enclosure of a building in excess of ten square feet (1 square meter) where a floor might otherwise be expected or measured, that is typically in the plane of the upper floors adjacent to multi-story atria or lobbies, light wells, auditoria or the area adjacent to a partial floor, permanent mezzanine or unclassified mezzanine at a given floor level.