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Glossary of Concepts for Real Estate Measurement


American National Standards Institute- helps to develop marketplace standards for safety, health, environment, etc. To participate in BOMA measurement standards development, a company must be ANSI accredited.

Area Analysis

A review, calculation and determination of the floor area in a building or portion of a building. An area analysis is normally produced as a tabular chart with accompanying floor plans and performed according to a specific method of measuring, most often a BOMA standard.

Area Certification

A document that definitively states the square footage of a building or space according to a standardized measuring methodology with references to supporting documentation such as a specific floor plan or area chart.

Area Chart

A tabular data chart that shows all calculated areas from a building area analysis.

Area Dispute Resolution

The process of hiring a neutral party to resolve a conflict over square footage between 2 or more parties.


A floor plan illustrating the current conditions of a space or building, and if applicable, the build-out of a space within a building.


The most widely used Computer Aided Design (aka CAD) software for 2D and 3D design and drafting, developed and sold by Autodesk.

Base Building Wall

A wall that is part of the building structure and can’t be removed or structurally changed. It is present for the lifetime of the building.

Basic Rentable Area

A specific step in calculating a tenant's Total Rentable Area according to BOMA 1996 Standard, in which the floor’s r/u ratio is applied to the usable area of the tenant.

Blue Print

A large format, scaled hard copy of an architectural drawing.

Blue Print Digitization

The process by which a blue print or other type of large format print on paper is converted to a digital file and stored on a computer, server, or a database. Digitization may involve document scanning to pdf just for archiving, or manual re-drafting into CAD software for editing.


The "Building Owners and Managers Association" is the primary source of information on all the standards related to commercial real estate: office building development, leasing and contracts, building operational costs, energy consumption patterns, local and national building codes, old and new legislation, occupancy statistics, tech developments, and more. For more information, go to http//

BOMA Standard

ANSI-approved measuring standards published by the Building Owners and Managers Association. The standards are updated about once every 15 years.

BOMA / SIOR Industrial 2004

This is the "Standard Methods For Measuring Floor Area in Industrial Buildings." BOMA/SIOR 2004 is a collaborative effort between three organizations that set standards for building measurement: BOMA, SIOR (Society of Industrial and Office Realtors) and AIR (The American Industrial Real Estate Association). Together, they produced a publication that outlines a standard method of measuring industrial buildings. This standard provides building owners with two methodologies. One is the Exterior Wall Methodology and the other is the Drip Line Methodology. Both methodologies are fundamentally similar to the BOMA 1996 office standard. BOMA/SIOR 2004 has been replaced with the ANSI approved "Industrial Buildings: Standard Methods of Measurement (ANSI/BOMA Z65.2-2009)". For more information, go here.

Building Amenity Area

Building Amenity Areas were introduced in the BOMA 2010 office standard. They are areas that provide a benefit or convenience to all occupants in the building. Examples include; vending areas, cafeterias, gyms, conference rooms, etc. Building Amenity Areas could become Occupant Areas easily if necessary.

Building Common Area

Areas within a building not specifically occupied by tenants but which serve and benefit all of the tenants in the building.

Building Service Area

Introduced in the BOMA 2010 office standard, Building Service Areas are those that provide a mandatory service to all tenants. Examples include: main lobbies, mechanical rooms, egress corridors, etc. Building Service Areas are permanent and unlikely to change over the lifetime of a building.

Building Core

The central area of a floor in an office building which generally contains the stairwells, elevator shafts, service shafts, mechanical areas and washrooms.


"Computer Aided Design" or "Computer Aided Drafting and Design" is the most popularly used term to refer to computer software which allows the user to draft scalable architectural or engineering drawings.

CAD Plan

A floor plan saved in any digital CAD format, but usually in AutoCAD’s .dwg format. Saving a CAD plan offers the ability to edit the floor plan using CAD software.

CAFM Integration

Computer Aided Facility Management uses IT systems and software to support facilities management. Existing conditions floor plans are usually integrated with CAFM software in the client's facilities management program.

Capped Gross-Up

Determining a maximum, or "not-to-exceed" gross-up factor for the rentable area. As an example: in lease offers, the landlord might say that the rentable area of the premises will be determined in reference to BOMA standards but with a capped gross-up of 15%. If the total gross-up under BOMA 1996 is more than 15%, the tenant will only pay for 15% gross-up and no more.

Color Schematics

A floor plan that incorporates color and legend to indicate certain aspects of the property. By providing color schematics, we illustrate how we have identified and calculated the different areas of a building according to BOMA measuring methodology.

Common Area

An area in a building that is not occupied by tenants but which serves and provides a benefit to the tenants in some way.

Complex Common Area

Areas in a building complex that serve and benefit all tenants in the complex.

Construction Area

Also known as Gross Building Area, the Construction Area is the full area of a building, measured to the outside walls, without deducting any area.


A computer system which stores a number of individual sets of data in order to make the data conveniently discoverable.

Demising Wall

A wall that separates one tenant space from another.

Disto Laser

A type of laser measuring devices, also referred to as a laser tape or laser tape measure. The Disto Laser determines distance by calculating the time it takes for the laser to make a round trip from the device to the wall (or any reflective surface) and back. It is a good intermediary tool between the traditional tape measure and the many LiDAR scanners available on the market.

Dominant Portion

Indicates which portion of a wall is vertically dominant. An example: if a wall from floor to ceiling is 40% glass and 60% drywall, the dominant portion is the drywall. If it is 60% glass and 40% drywall, the dominant portion is glass.

Drip Line Methodology

Drip Line Methodology is also known as "Method B" in the Industrial Buildings: Standard Methods of Measurement (ANSI/BOMA Z65.2-2009). This method calls for measurement to the most exterior drip line at the perimeter of the roof system for area calculations.

Due Diligence

Strategically acting to avoid potential future liability by proactively making sure all provided information is accurate.

DWG Plan

An AutoCAD file of a floor plan or 3D model of the space. DWG files are useful for architects, designers, engineers or any party that needs the ability to edit a floor plan.

Exterior Wall Methodology

Also known as "Method A" in the Industrial Buildings: Standard Methods of Measurement (ANSI/BOMA Z65.2-2009). This method measures to the outside of exterior walls for area calculations.

Feasibility Study

When a tenant wants to move into a building, they must take into consideration the amount of area required and what is currently available - is it feasible for them to rent this space given their needs?

Feature Sheet

A document that highlights important features and amenities of a space. Feature sheets frequently include as-built floor plans, feasibility plans and site plans, as well as maps and key contact information.

Finished Mezzanine

A finished mezzanine is possible to use for personnel. For a mezzanine to be considered finished, it must be full height, have HVAC, and be finished to comply with local occupancy codes. Finished mezzanines are specified in the Industrial Buildings: Standard Methods of Measurement (ANSI/BOMA Z65.2-2009) as being included in the Rentable Area of the building as long as all parties agree.

Fixed Gross-Up

Determining the rentable area of a tenant by applying an unchanging and pre-determined gross-up to the tenant's usable area. This practice can be used on a suite by suite, floor by floor or building-wide basis and is often used to avoid high and fluctuating BOMA 1996 gross-ups.

Floor Amenity Area

Floor Amenity Area was introduced in the BOMA 2010 office standard. It is a common area providing conveniences to the occupants only on that floor.

Floor Common Area

Similar to Floor Amenity Area, the Floor Common Areas are areas of a floor in a building that are not specifically occupied by tenants, but which serve and benefit that floor’s tenants only.

Floor Service Area

Floor Service Areas were introduced in the BOMA 2010 office standard. They provide mandatory services to the occupants on that floor, which includes bathrooms, electrical closets, mechanical rooms, etc.

Floor Plate

The Floor Plate is a floor plan containing common and repeating attributes of a multiple story building. It can be used as a template when measuring multiple floors of a building, but only if that building repeats the same floor plan on multiple floors.

Gross Building Area

Also referred to as the Construction Area, the Gross Building Area is the entire area of a building measured to the outside walls without any deductions.


A Gross-Up is a pro-rata or predetermined fixed increase in a tenant's area, usually expressed as a percentage. Normally a Gross-Up is applied to the usable area of a tenant in order to compensate for the operating expenses in a building.

Key Plan

A graphic, or key, that’s incorporated within a floor plan illustrating the location of a suite, unit or other type of space.

Load Factor

Also described as Gross-Up Factor or R/U Ratio (Rentable over Usable), the Load Factor represents the prorated common areas that a tenant must pay for - expressed as a ratio or percentage. To determine the tenant’s Rentable Area, the Usable Area is multiplied by the Load Factor. See the definition for R/U Ratio for more information.

Loss Factor

The Loss Factor is the percentage difference between the Rentable Area (the number of square feet that tenants pay for) and the Usable Area (the number of square feet each tenant physically occupies).

Major Vertical Penetration

The areas in a building which penetrate the floor slab: this includes stairs, elevator shafts, flues, pipe shafts, vertical ducts, etc. BOMA standards specify that these areas and their enclosing walls are explicitly excluded from the rentable area of a building.

Modified BOMA

A client might request an adjustment of a BOMA area analysis if the strict application of BOMA ends up with unfavorable results - such as a gross-up factor that is larger than what the market will allow for.

Occupant Area

The real tenant-occupied space in a building, without alteration or gross-up applied. This concept was introduced by the latest BOMA standards, where Occupant Area replaces the BOMA 1996 Usable Area.

Partition Wall

A wall placed to break up a tenant's space inside the boundary walls of their Rentable Area.

Private Common Area

Similar to a Common Area, the Private Common Areas of a building are exclusively and proportionately shared between one or multiple tenants.


The calculation used to determine the correct proportionate allocation of space in the premises.

R/U Ratio

The R/U Ratio is the Rentable Area divided by Usable Area. It is a method of calculating proportionate share allocations, and therefore the rentable areas of tenants. It is often used to determine the amount of common area space that a tenant has to pay for, keeping in consideration the amount of usable area that each tenant occupies. The result from dividing the total rentable area of a floor or building by the total usable area of a floor or building provides a gross-up factor that converts to a percentage, then multiplied to each individual tenant’s usable area, which defines each individual tenant’s rentable area.

Reflected Ceiling Plan

"RCP" or Ceiling Plan is a scaled drawing of the ceiling as if you are above the ceiling, looking down. RCP's will show elements like lights, drop-ceiling tiles, emergency lighting, exit signs, exhaust fans / hoods, air diffusers / vents, access panels, speakers, sprinklers, fire alarms, etc.

Separation Plan

The plan of an individual unit extracted from the full floor plan. Separation plans include a key plan: a graphic in the plan that illustrates the location of the unit in the building. Separation plans are often used for marketing to potential tenants.


The "Society of Industrial and Office Realtors" is an association of commercial and industrial real estate professionals. When it comes to building measurement, SIOR is known for developing a standard method of measuring industrial buildings. For more information, go to

Space Plan

A floor plan that shows options for potential wall or furniture layouts.

Storage Mezzanine

Different from a Finished Mezzanine, the Storage Mezzanine is built to comply with local building codes for storage use only - no personnel. Storage Mezzanines are specified in the Industrial Buildings: Standard Methods of Measurement (ANSI/BOMA Z65.2-2009) as being included in the Rentable Area of the building as long as all parties agree.

Total Rentable Area

The area of a premises with all gross-ups applied, also known as the total area of a premises in which the landlord will charge rent to a tenant.

Unfinished Mezzanine

A mezzanine which is not suitable for use by personnel and can only be used for storage. Normally, an unfinished mezzanine is not included in the rentable area of a building.

Usable Area

The actual tenant-occupied area of a premises without any alterations or gross-ups applied.



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