BAM Building Area Measurement LLC

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PO Box 9936
Denver, CO 80209
Phone: 303-795-2148
Fax: 720-294-1286

Frequently Asked Questions

Property developers, managers, tenants and design professionals have posed the following general questions relating to building area measurement. The answers are my own advise, based upon my experience and knowledge of current standards and practices.

Should the lease state the square footage leased or occupied in the premises?

There are no laws requiring utilization of building area measurement standards or inclusion of square footage in the lease. Some landlords prefer to omit reference in the lease to square footage, employing aggregate rental for space, or using disclaimer clauses. Some landlords cite square footage figures but use “deemed as” language in an effort to legislate the rentable area for the purposes of the lease. Others, recognizing that the amount of measured floor area is central to the concept of leasing space at rent rates expressed in monetary units per square foot (or square meter), cite a standard and a rentable area for the premises. Practices and opinions vary on this issue, and there is no clearly right answer for all situations. Consultation with an attorney with expertise in this area is advised.

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Should the lease include a tolerance in area measurement, and what should it be?

Because it is practically impossible for two qualified parties to measure the same space and come up with the exact same measurement (even using the same standard), a tolerance is an important feature to avoid expensive arguments over relatively small differences. A lease employing the BOMA or GWCAR Standard need not specify a tolerance because the tolerance is specified by the standard. If closer tolerances are required or if other standards are used, the lease should specify an appropriate tolerance.

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Should the lease contain a plan of the leased premises?

A plan of the premises is frequently an exhibit in the lease and is the clearest way to graphically describe the premises, especially when the lessor occupies less than a full floor. Plans should be clearly prepared, indicating the context of the premises (floor, location, floor common areas), demising walls with dimensions (unless plan is accurately drawn and plotted to scale), and points of entry/exit to/from the premises. Even for full floor tenants, a plan of the premises/floor can be useful in indicating areas the must be accessible by the landlord for maintenance, or areas such as communications risers, which tenant is not allowed to use for their storage, equipment and the like

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Should a lease for space in a new building give the tenant the right to adjust the rentable area based on physical measurements when the space is finished?

See “Should I physically measure the premises” below and insert appropriate lease language and tolerance requirements if necessary.

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Why are there published standards for building area measurement?

Published measurement standards offer the ability for tenants to compare rentable areas between properties in a market on an “apples-to-apples” basis. They are also fundamental to landlords and facility managers ability to benchmark operating costs per square foot. Published standards are well documented and their terminology and application are generally well understood within the industry, permitting clear and understandable communication.

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Should I cite a published building area measurement standard for doing area calculations?

Use of a recognized measurement standard can be an advantage in leasing space in addition to the benefits mentioned above (see “Why are there published standards…". However, if you cite a standard, you become committed to following it. At a minimum, obtain a current copy of the standard and fully understand its application (or employ someone who does).

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Can I make up my own measurement method?

Documenting a custom building area measurement standard that adequately addresses the same scope of generic conditions addressed by published standards requires time, expertise and funding that is beyond the capability of most smaller developers and building managers. However, a standard written for a particular building can be very simple. Several large developers, property management firms and corporations have developed their own private measurement standards.

Amateurish efforts to draft a measurement standard by cribbing a few popular phrases from published standards (such as “No deduction shall be made for columns and projections necessary to the building”) often lead to obfuscation and disagreement. Many landlords base a custom standard on one of the major published standards (see question on “Modified BOMA”).

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Which published measurement standard should I use to measure space?

This depends upon the market in which the property is located and the purpose of the measurement. The BOMA Office Standard is the predominant standard for leasing office space in the US and Canada outside New York and Washington, DC, where the REBNY and GWCAR standards prevail. The The recently introduced BOMA Industrial Standard is expected to likewise dominate in industrial facilities, replacing the AIR standard which was for 11 years the only published industrial measurement standard. The IFMA Standard is used nationally for space planning and management (not leasing) and the AIA Standard is employed in construction cost estimating. See more details elsewhere on this web site.

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Who should do building area measurements?

Architects are generally the most qualified to determine building area measurements by virtue of their knowledge and tools. However, care should be taken that the specific personnel employed by the architectural firm have expertise in applying the measurement standard being used. Measurement standards are not taught in architecture schools or covered in architectural licensing exams. See question on "Who should certify…” below.

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Should building area measurements be certified?

Tenants, lending institutions and insurance companies, sometimes require certified building area measurements. Certification is a contractual term that gives the certificate holder additional legal remedies beyond those offered by normal errors and omissions (such as recourse against intentional misstatements). Certification is meaningful only if there is recourse, which generally requires applicable insurance on the part of the certifier.

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Who should certify building area measurements?

There is no statutory authority in any state that sets standards for who can or cannot certify building area measurement. The certificate holder must rely upon the skills, reputation and assets (including insurance) of the certifying firm or individual. Architects professional errors and omissions insurance generally covers negligence and errors within the limits set by the normal standard of architectural practice, but excludes coverage for certifications, which is why architects frequently refuse to certify area calculations. Qualified firms that have contractual liability coverage, like Building Area Measurement LLC, offer more meaningful certification when it is required.

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What is meant by the term “Modified BOMA”?

Landlords commonly modify the BOMA Standard in three basic ways:

  1. How allocation of common area is done (such as use of a single average R/U Ratio for all floors of a building),
  2. How space is measured (such as measuring Gross Measured Area to the outside face of the building instead of the Dominant Surface), and
  3. How space is classified (such as including exterior balconies as usable or building common area, or including toilets in the usable area of full-floor tenants).
Use of the term "Modified BOMA" by itself is ambiguous and can be misleading. Whatever specific modifications are made must be carefully described and documented along with the citation of the BOMA Standard. This same principle applies to modified applications of other standards.

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Should I physically measure the premises, or is it good enough to measure area using construction documents?

All buildings have construction tolerances that vary by building age, construction type, contractor skill and other factors. Changes made in the field that are not reflected on floor plans are often more significant than construction tolerances, but the impact of these can be minimized by using contractor-prepared “as-built” drawings as the basis for measurement. Consider construction tolerances along with the lease rate to determine the likely financial impact of post-construction field measurement of building areas. If the space is built, it is usually best to check at least the most significant dimensions to avoid surprises.

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Can I scale building areas off floor plans, or is more documentation required?

Floor plans prepared for construction are technical documents meant to indicate relationships between building systems. Floor plan are often schematic, and many relevant detail dimensions, such as the location of the inside face of exterior glazing, are shown on detail drawings elsewhere in the construction documents. For this reason, area measurements prepared only from plans, without reference to other parts of the construction documents, or field dimensions, can be inaccurate. A full set of architectural and structural construction or as-built documents is the normal minimum set of documents required to perform accurate building area measurements. Lacking this, field dimensions of major significant dimensions are highly recommended for accurate measurements.

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What are the most significant dimensions to field check?

For most buildings, locating the boundary of the gross measured area is the most critical dimensioning task, followed closely by locating the boundary of major building core elements.

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How can I determine the area of a building or space for which there are no existing plans (paper or CAD)?

It is not necessary to prepare complete as-built floor plans (a costly process that runs upwards of $0.10 per SF and includes doors, columns and other elements irrelevant to lease area measurements) in order to determine building area measurements. Only the wall or window surfaces that are significant in determining usable and rentable areas need be located by field measurement. Usable areas of any suite can be computed inexpensively, but, when using the BOMA or GWCAR standard, the entire property must be so measured to determine the Rentable Area of any one suite.

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What is meant by the term “Net Rentable Area”?

This term should be carefully defined by the entity using it. It is not defined under any major published building area measurement standard. It has been replaced by the term “Rentable Area”.

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What is the “Dripline Standard”?

For many years, there was no published document that defined this measurement method popular in the southern regions of the U.S. As of October, 2004, it is defined in the BOMA Industrial Standard as Method B, the Drip Line Methodology.

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Does CAD (Computer Aided Drafting) give more accurate area measurement from plans than “manual” calculation?

Careful and accurate manual area calculations done with good quality control are more time-consuming to do, but are no less accurate than CAD based measurements.

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When I’m measuring space, how accurate do dimensions have to be?

It is an accepted standard in the construction industry to use 1/8” (approx. 0.01 foot or 3mm) as the smallest normal dimensional increment on floor plans. It is both convenient and appropriate to carry this tolerance into dimensions used for building area measurements.

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Is it okay to round off square foot areas?

To avoid excessive rounding error in most properties, keep all working square footages rounded off to the nearest 0.01 square foot. Only for leases and quotes should you round off to the nearest whole square foot for Rentable and Usable Areas.

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How many decimal places should I use in my R/U Ratios?

Four significant places (1.1234) will work in the R/U Ratio for most properties under 1,000,000 SF as rounding errors should be less than 100 SF at that limit. For properties over that limit, consider using five places (1.12345) in the R/U Ratio.

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What are the best measuring tools to use to physically determine floor area?

Measuring tapes (steel or fiberglass) and laser distance-measuring equipment (DME), skillfully employed, are the best building area measurement tools. Acoustical DME, measuring wheels, and GPS do not currently have enough accuracy for leasing applications but can be useful for rough area calculations.

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What are the acceptable tolerances in measurement of floor area?

The BOMA and GWCAR Standards both cite a 2% tolerance, which is the accepted standard in the industry. Some private standards and lease language for large tenants in high rent areas require tolerances as low as 0.25%, a tolerance that may exceed construction tolerance and require field verification.

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What kinds of errors can lead to incorrect building area measurements and leased areas?

Errors can be made in many ways, including but not limited to:

  1. Misunderstandings based upon inadequate communication or documentation (what floor, what space plan version etc.),
  2. Inadequate understanding of the standard being applied to measure space,
  3. Poor quality control procedures, especially in rush situations common in leasing,
  4. Erroneous inclusion or omission of space measured under a standard,
  5. Errors in classification of space measured under a standard,
  6. Errors in locating the boundary line of a space (dominant surface, side of wall),
  7. Errors cause by inaccurate plans (drawn wrong or not to scale),
  8. Dimensional errors (nonsensical geometry),
  9. Calculation errors in computing raw areas,
  10. Calculation errors in allocation of common areas (applying R/U factors),
  11. Inadequate systems of accounting for square footage over time.

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Where do most errors arise in measurement of space?

Poor communication is the leading cause of significant errors, with poor understanding of the standard being used a close second, and errors stemming from poor quality control in doing and tracking area calculations a strong third place.

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How big does a dimensional error in locating the dominant surface have to be to result in a 2% error in Rentable Area?

If you assume a square building 150 feet on a side (22,500 SF GMA per floor), a 9” dimensional error in locating the dominant surface on each side of the building will lead to a 2% error (450 SF) in the GMA of a floor. Since Rentable Area is less than GMA (varies based upon building design), the critical dimensional error would be less than 9”, possibly around 8” for this example. Dimensional errors for smaller core elements have to be much larger to yield a 2% error in Rentable Area. A floor plan that is reproduced by copying or faxing can easily change scale by 1% to 2% each time it is copied or faxed.

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What quality control procedures are most effective in preventing errors in building area measurements?

Quality control must address each of the sources for error cited above, and include good communication within the project team, training in understanding and applying standards, good measurement tools and resources with skills in applying them, and excellent documentation and record-keeping.

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What documentation should be produced for building area measurements?

The typical “letter from the architect” does not provide enough documentation. At a minimum, and building area measurement should be accompanied by a measurement diagram similar to a lease exhibit (see “Should the lease contain a plan…” above) and cite the specific location, space plan version, date and the standard used for measurement. If the measurement is certified, the name of the certificate holder must be specified.

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What constitutes good record keeping for firms who perform building area measurements?

Accounting for square feet is like accounting for money. Attention and effort have to be expended to establish a formal system to track measurements made and applied to leases. It doesn’t matter what form this system takes, but it should be significantly better that a typical architectural project file containing only a stack of old “bum wads” with pencil scratchings meaningful only to their authors. An effective database can be maintained using organized 3-ring binders and columnar pads, or a database in Excel or Access with archived CAD files, or using specialized custom software.

Many architectural firms become mired in documents and keep them only as long as they are required under the statutes of repose and limitations in their state. In some states, this is as short as 7 years. Leases often extend for longer periods of time, which requires that record-keeping for building area measurements be accomplished differently than normal architectural “project file” record keeping.

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Copyright © 2005 by Building Area Measurement LLC
This page revised on 23-Jun-05