Building Measurement Services

Measuring and calculating the areas of properties and buildings is an important part of what architects do. Most often, however, this aspect of the architect`s work is performed not as an end in itself but to support other activities and services. For example, determining the area of a building lot, property, or acreage—as well as individual site elements such as roads, parking, and so on—is
important in site design and development. In zoning analysis, the size of the property area along with the building area and its footprint are used to calculate the floor-to-area ratio (FAR), required parking spaces, and other zoning benchmarks.

An important use for building area and square foot cost data is in the development of preliminary cost estimates. Building area is also employed—usually with higher levels of detail and accuracy—for detailed cost estimates and development of construction bids. In facility management, building areas are used to track occupancy by department and type of space. This information is used for strategic planning, expense recovery, and cost allocation. Beyond the uses and applications just mentioned, the calculation of building area can be performed as a stand-alone service. In this case, measurements and calculations are made to determine various factors used in analyzing and developing commercial building leases for which floor area is a primary consideration. This topic discusses the basics of offering building measurement services for these purposes.

Market for Measurement Services

In the last 25 years the total supply of office space in the United States has doubled to almost 12 billion square feet in approximately 800,000 buildings. According to a 1995 survey conducted by the Energy Information Administration, more than 84 percent of all office buildings are owner-occupied. If we consider the 16 percent of office buildings that are presumably leased or available for lease, the market for building measurement
services is at least 1.8 billion square feet, or 120,000 buildings and growing.

As the market size has grown, so have the number of firms offering building measurement services. As of 2002, about a dozen firms specialize in building documentation and rentable area calculation. Several hundred architecture and interior design firms also have experience in this field.


Architects are well positioned and qualified to provide building owners with building measurement services. However, some architects may need to become more familiar with and knowledgeable about standard methods and variations used to formulate rentable area in commercial offices buildings.

Measuring Tools and Equipment
Actual dimensions of constructed spaces rarely if ever are the same as those shown on construction documents. During construction, changes—some of which are significant—may have been made that are not reflected on available drawings. Therefore, in dealing with existing buildings, taking field measurements is always advisable, if not mandatory.
Field measurements can be carried out with standard measuring tapes (e.g., up to 25 feet, 50 feet, and 100 feet) to accommodate varying conditions. However, consider investing in laser measuring devices to supplement conventional tapes. Laser devices only require one hand to operate, are relatively inexpensive, are accurate, can save time since they don`t need to be rewound after each measurement, and may have the ability to provide readings in metric units as well as English units.


Several options and combinations for carrying out building measurement services are available to accommodate the tasks and activities required by the nature and needs of aparticular project. Following are brief discussions of these opportunities.

Service Options

The scope of measurement services will depend on the type, amount, and accuracy of information supplied by the client. The nature of the project and the information provided by the client influence which measurement services are suitable. The following represent possible clusters of building measurement services:

  • Area calculations and reports from client-supplied CAD drawings
  • Creation of CAD drawings from client-supplied dimensioned, as-built drawings
  • Creation of CAD drawings from plans and spot measurements
  • Creation of CAD drawings entirely from on-site field measurements
  • Survey of existing corridors and tenant demising walls
  • Integration of lease information into rent books for landlords (for tracking vacancies, renewal options, rate escalations, subtenants, etc.)

Process Increments and Tasks

The options listed above may embody some or all of the increments described below. While many tasks within these increments are performed sequentially, some may be carried out concurrently or in an overlapping fashion to respond to opportunities to access spaces, schedule requirements, staff availability, etc.

Acquiring or Developing Plans

If a client says building plans for spaces to be analyzed are not available, take time to look for them. Hundreds of hours of surveying time can be saved if plans can be located. Look behind the boiler or in the attic storage. Try contacting the original architect and engineer, the local building department, or historical archives. If drawings are not available, they will have to be created from field surveys and measurements of the floor areas
for which area calculations are needed.

Field Measurement

Preparation is key. Create a checklist of necessary items, including existing drawings, tenant lists, contact and key personnel information, clipboard, measuring devices, camera, flashlight, and so on. If you are traveling out of town, take a laptop computer so you can prove your measurements before you leave. Speak with the building manager at least a week before your arrival so that he or she will have time to notify sensitive tenants and schedule one or more workers to accompany you throughout the building. In some cases, your access may be limited to weekends or times after normal business hours. Measuring demising walls on multitenant floors can be challenging. To avoid incremental rounding errors, always start at a window mullion or some other fixed position on the exterior wall and work toward the corridor. Double-check your dimensions by
measuring to a door or corner on the corridor wall.

Area Calculations, Analysis, and Space Allocations

Computerized area calculation usually involves drawing closed polylines around the spaces being measured. Care must be taken not to overlap other polylines, since that would prevent the sum of the parts from equaling the whole. (You can test for this by drawing a polyline around the perimeter.) Area is one of the displayable properties of a polyline. It can be manually entered into a ledger or linked to another drawing object using attributes (category, space type, room number). The advantage of linking is that a program can be written to extract this data directly into a database or spreadsheet. Adequate time should be given to analyzing the results of your rentable area calculations. It is important, for instance, to be sure the usable and rentable areas of like floors are the same. In cases where there are minor differences, you should be able to explain this. Did a shaft become narrower? Was there a setback on this floor? If there is no physical reason for the difference, you may want to check the polylines in your floor plan file or the accuracy of your allocation factors. Sometimes changing the factors from three to five decimal places solves this problem.