HomeMy WebLinkAboutLexington Gross Floor Area CalculationCalculation for Floor Area Ratios (GFA)
Address: _________________________________ Lot Size: ___________________
Maximum Allowed GFA:
Existing and Proposed GFA:
*Square footagesmust have
documented areas on
a floor plan showing
how square footage
was calculated.
Confirm Building
Plans delineate Gross
Floor Areas.
___________________________________ ___________________________________ _____________
Architect Name Architect Signature Date
Lot Area
(in square feet)
Maximum GFA
(in square feet)
0 to 5,000 0.8 * Lot Area
5,000 to 7,500 4,000 + 0.55 * (Lot Area - 5,000)
7,500 to 10,000 5,375 + 0.23 * (Lot Area - 7,500)
10,000 to 15,000 5,950 + 0.2 * (Lot Area - 10,000)
15,000 to 30,000 6,950 + 0.16 * (Lot Area - 15,000)
More than 30,000 9,350 + 0.16 * (Lot Area - 30,000)
Maximum Allowed GFA:
Area Existing Square Feet Proposed Square Feet*
Basement: ceiling height of
at least 6’8”
Garage
First Floor
Second Floor
Half Story (Max.40% of
Second floor)
Porch(s)
Any Other Structures on
Property (Sheds, etc.)
Total GFA
GROSS FLOOR AREA
The sum, in square feet, of the horizontal areas of a building (or several buildings on the same lot)
measured from the exterior face of the exterior walls, or from the center line of a party wall separating
two buildings, including garages, basements, porches, and half stories. In half stories, all floor area
where the headroom is greater than five feet, measured from the top of the floor joists of the top story
to the bottom of the roof rafters, which is included in the measurement of gross floor area unless the
term net floor area is used.
HALF STORY (An Attic with Stairway Access)
A story under a sloping roof accessed by a stairway complaint with the building code. The gross floor
area with head room of five feet or more may not exceed 40% of the total floor area of the second story.
Dormers may be constructed on those exterior walls provided the length of the dormers measured
between the lowest bearing points of the dormers on the rafters of the sloping roof does not exceed 50%
of the length of the sloping roof to which it is attached.
See Bylaw Table 4.4.2