When Is Floor Area Not Floor Area?

By Austin Regan, R.A.

How big is that space? It seems a simple enough question. Your living room needs a new floor. You get out the tape measure. Measure the length. Check the width. Multiply. Now you know how many square feet of flooring to buy.

Simple math becomes more complicated when a space, apartment, or building is measured for other purposes. That 383 s.f. apartment may mysteriously expand to 400 s.f. when listed by the rental agency. Although no more furniture can fit, you may be told for tax purposes your condo is 425 s.f., as the Department of Finance takes measurements to the centerline of walls and includes the balcony.

Zoning Floor Area

When trying to figure out how big a new building can be, the tape measure (or CAD equivalent) tells but part of the story. The zoning resolution determines the bulk of a proposed building. Depending on the building type and the project location, a Floor Area Ratio (FAR) is assigned to the property. Expressed as a number, FAR represents a multiplier that is applied to the lot area of the property. The product of that equation represents the maximum amount of zoning floor area allowed on the property. For example, a property with a FAR of 3.0 can have zoning floor area equal to a maximum of three times the lot area. If the lot area is 5,000 s.f., then the maximum zoning floor area allowed equals 15,000 s.f.

Notice how we did not say the floor area equals 15,000 s.f. We said maximum zoning floor area. We also purposefully italicized the words “floor area” because that is what city planning does in the printed version of the zoning resolution to every word or phrase that is defined in Section ZR 12-10 of the resolution. (In the online version of the resolution, hashtags surround defined terms (e.g., #floor area#). We’re not sure why; it might be a Twitter thing.)

Zoning Deductions

Not only is “floor area” a defined term, but the explanation of what constitutes floor area also takes up three pages. The explanation of what does not constitute floor area fills six! Architects spend many hours studying those six pages. Properly utilizing and identifying areas considered not floor area, or “zoning deductions,” can add additional stories to a building and bring additional value to ownership.

Many of the zoning deductions are straightforward and add significantly to the gross floor area of the building. Cellars and subterranean levels below cellars, for instance, do not count as floor area. Parking structures less than 23 feet above curb level normally do not count. Many roof bulkheads can be deducted from floor area.

Understandably, DOB carefully scrutinizes zoning floor area deductions. The architect serves her cause well by submitting the right presentation. The first step is to understand how to measure the overall zoning floor area for a floor. Below is the beginning of the ZR 12-10 definition:

“Floor area” is the sum of the gross areas of the several floors of a #building# or #buildings#, measured from the exterior faces of exterior walls or from the center lines of walls separating two #buildings#.

The thickness of the exterior wall counts as part of the floor area. In a high-rise building counting that six-, eight- or 12-inch thickness can add up to significant square footage. A relatively recent addition to allowable zoning deductions is extra-thick walls that provide superior energy efficiency.

(i) “where such wall thickness is part of an exterior wall constructed after April 30, 2012, equal to the number of inches by which the wall’s total thickness exceeds eight inches, provided the above-grade exterior walls of the #building# envelope are more energy efficient than required by the New York City Energy Conservation Code (NYCECC) as determined by the following:

1. 1. the area-weighted average U-factor of all opaque above-grade wall assemblies shall be no greater than 80 percent of the area-weighted average U-factor determined by using the prescribed requirements of the NYCECC; and
   2. the area-weighted average U-factor of all above-grade exterior wall assemblies, including vertical fenestrations, shall be no more than 90 percent of the area-weighted average U-factor determined by using the prescribed requirements of the NYCECC. For the purposes of calculating the area-weighted average U-factor, the amount of fenestration shall equal the amount of fenestration provided in such exterior walls, or an amount equal to the maximum fenestration area referenced in the NYCECC for the calculation of the baseline energy code requirement, whichever is less; “

Proving that your building can qualify for the energy (sometimes called Zone Green) deduction requires a separate presentation that also ties into your energy analysis. We are not going to discuss that in this article. Instead, we’ll look at the deduction for “floor space used for mechanical equipment”.

Mechanical Equipment Deductions

The definition does articulate restrictions for some low-density residential districts, but it gives no guidance or restrictions for high-density residential (R6 –R10) or commercial and manufacturing districts. Interpretations regarding what constitutes mechanical equipment started appearing in the 1960s, with some commonly accepted building components being permitted for deductions. For example, shafts containing mechanical ductwork are accepted as a mechanical deduction, as are plumbing wet walls containing risers. Over the years, various interpretations have differed from borough to borough and examiner to examiner regarding whether the enclosing walls of the risers and shafts could also be deducted. Currently, the trend among DOB examiners is to permit the deduction of all shafts (except elevator), including the enclosing wall thickness.

The enclosing walls of mechanical rooms, however, are not deductible. Following the definition, you are allowed to deduct space used for mechanical equipment only. Because of past abuses of this deduction, examiners insist on reviewing mechanical and plumbing plans to verify that the room is reasonably sized for the equipment shown.

While DOB is now fairly consistent regarding what items they need to justify a mechanical room deduction, a wide disparity remains in interpreting what is considered a mechanical room. Examiners, for instance, routinely object to the deduction of electrical rooms. Also, pump rooms, meter rooms, and RPZ closets have all been accepted by some examiners but rejected by others. Normally, if needed, DOB will grant a determination to allow the above items. What the DOB will not allow is the deduction of IT rooms or closets that contain low-voltage equipment. Back in 2012, the DOB did try to standardize acceptable mechanical deductions via a Building Bulletin. After working on it a few years and issuing numerous drafts, the effort was abandoned.

As a result, permitted mechanical deductions are still somewhat subject to the whims of individual examiners. In every case, it is important to present the deduction analysis logically and coherently. Dedicated drawings dealing only with the zoning floor area deductions must be produced. Each individual deduction must be labeled and dimensioned. Those dimensions must be supported by the construction plans, and the corresponding square footages must be presented in a tabular format.

A good, easy-to-follow presentation will go a long way to satisfy the examiner. If examiners feel comfortable with what they are seeing, they will be less inclined to scrutinize every deduction and dimension.