23-71 Minimum Distance Between Buildings on a Single Zoning Lot
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In all districts, as indicated, the minimum distance between the portion of a building containing residences and any other building on the same zoning lot shall be as provided in this Section. For the purposes of this Section, abutting buildings on a single zoning lot may be considered a single building.
However, these provisions do not apply:
(a) to the extent that such two buildings are separated from each other by a rear yard equivalent as set forth in Section 23-532 (Required rear yard equivalents) or 23-533 (Required rear yard equivalents for Quality Housing buildings), as applicable; or
(b) to space between a single-family, two-family, or three-family residence and a garage accessory thereto.
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In all districts, as indicated, the required minimum distance between the portion of a building containing dwelling units and any other building on the same zoning lot shall vary according to the height of such buildings and the presence of legally required windows in facing building walls. Such minimum distance shall be, in feet, as indicated in the following table:
Maximum Building Height above Base Plane or Curb Level, as Applicable (in feet)
Wall to Wall
Wall to Window
Window to Window
* Wall condition shall be defined as:
"wall to wall" is a condition where two walls of buildings face each other, and neither wall contains a legally required window ;
"wall to window" is a condition where two walls of buildings face each other, and one wall contains a legally required window and the other wall does not contain a legally required window ;
"window to window" is a condition where two walls of buildings face each other, and both walls contain a legally required window.
In addition, the following rules shall apply:
(a) the minimum distances set forth in this table shall be provided at the closest point between buildings ;
(b) any portion of a building that qualifies as a building segment may be treated as a separate building for the purposes of determining the minimum distance required between such building segment and another building or building segment ;
(c) where buildings of different heights face each other, the average of the heights of such buildings shall determine the minimum distance required between them;
(d) projections having a maximum height of 25 feet above adjoining grade, a maximum depth of five feet, and an aggregate width not exceeding 25 percent of the building wall from which they project, may penetrate the minimum spacing requirements;
(e) portions of buildings above 125 feet that exceed, in aggregate, a lot coverage of 40 percent, shall be spaced at least 80 feet apart;
(f) in R1, R2, R3, R4A and R4-1 Districts within lower density growth management areas, the provisions of this paragraph, (f), shall apply to any zoning lot with two or more buildings where at least 75 percent of the floor area of one building is located beyond 50 feet of a street line and the private road provisions do not apply. For the purposes of this paragraph, any building containing residences with no building containing residences located between it and the street line so that lines drawn perpendicular to the street line do not intersect any other building containing residences shall be considered a "front building," and any building containing residences with at least 75 percent of its floor area located beyond the rear wall line, or prolongation thereof, of a "front building" shall be considered a "rear building." The minimum distances set forth in the table in this Section shall apply, except that a minimum distance of 45 feet shall be provided between any such front and rear buildings ; and
(g) for buildings existing on April 30, 2012, the minimum distances set forth in the table in this Section, and any non-complying distance greater than eight feet, may be reduced by up to eight inches of exterior wall thickness, provided the added wall thickness has a thermal resistance (R-value) of at least 1.5 per inch. A non-complying distance of eight feet or less shall be limited to a total reduction of one inch of wall thickness for each foot of such existing distance between buildings.