This method measures the actual occupiable area of a floor or an office suite
and is of prime interest to a tenant in evaluating the space offered by a
landlord and in allocating the space required to house personnel and furniture.
The amount of Usable Area on a multi-tenant floor can vary over the life of a
building as corridors expand and contract and as floors are remodeled. Usable
Area on a floor can be converted to Rentable Area by the use of a conversion
This method measures the tenant's pro rata portion of the entire office floor,
excluding elements of the building that penetrate through the floor to areas
below. The Rentable Area of a floor is fixed for the life of a building and is
not affected by changes in corridor sizes or configuration. This method is
therefore recommended for measuring the total income-producing area of a
building and for use in computing the tenant's pro rata share of a building for
purposes of rent escalation. Lenders, architects and appraisers will use
Rentable Area in analyzing the economic potential of a building.
It is recommended that on multi-tenant floors the landlord compute both the
Rentable and Usable Area for any specific office suite.
"Finished Surface" shall mean a wall, ceiling or floor surface,
including glass, as prepared for tenant use, excluding the thickness of any
special surfacing materials such as paneling, furring strips and carpet.
"Dominant Portion" shall mean that portion of the inside finished
surface of the permanent outer building wall which is 50% or more of the
vertical floor-to-ceiling dimension measured at the dominant portion. If there
is no dominant portion, or if the dominant portion is not vertical, the
measurement for area shall be to the inside finished surface of the permanent
outer building wall where it intersects the finished floor.
"Major Vertical Portion" shall mean stairs, elevator shafts, flues, pipe
shafts, vertical ducts, and the like, and their enclosing walls, which serve
more than one floor of the building, but shall not include stairs,
dumb-waiters, lifts, and the like, exclusively serving a tenant occupying
offices on more than one floor.
"Office" shall mean the premises leased to a tenant for which a measurement is
to be computed.
Rentable Area = Rentable/Usable Ratio
Usable Area = 1"R/U Ratio"
Usable Areas R/U Ratio = Rentable Area
Rentable Area = Usable Area
The Rentable Area of a floor shall be computed by measuring to the inside
finished surface of the dominant portion of the permanent outer building walls,
excluding any major vertical penetrations of the floor.
No deduction shall be made for columns and projections necessary to the
The Rentable Area of an office on the floor shall be computed by multiplying
the Usable Area of that office by the quotient of the division of the Rentable
Area of the floor by the Usable Area of the floor resulting in the "R/U Ratio"
The Usable Area of a floor shall be computed by measuring to the finished
surface of the office side or corridor and other permanent walls, to the center
of partitions that separate the office from adjoining Usable Areas, and to the
inside finished surface of the dominant portion of the permanent outer building
No deductions shall be made for columns and projections necessary to the
building. The Usable Area of a floor shall be equal to the sum of all Usable
Areas on that floor.