Applying New Code Standards to Prior-Code Structures: Enlargements

By John Lashley

As covered last month, Section 28-101.4.3 of the New York City Administrative Code (AC) says the following regarding “Optional use of the 1968 building code for work on prior code buildings”:

At the option of the owner, and subject to applicable provisions of this code, work on prior code buildings may be performed in accordance with the requirements and standards set forth in the 1968 building code, or where the 1968 code so authorizes, the code in effect prior to December 6, 1968.

This month, we’re exploring the circumstances in which an entire prior-code building must adhere to the current code, as if it were a new building.

Building Enlargement

When the square footage of an existing building is expanded beyond a certain percentage, AC Section 28-101.4.5 requires that the entire building must comply with current construction codes. Specifically, if the floor surface area (FSA) increases by more than 110%, then the building must follow the same requirements as a new building.

The AC defines FSA as “the gross square feet area of all horizontal floor and roof surfaces, including roof of bulkheads and superstructures, of a building or structure at any level, including cellar, attic and roof.”

Calculating FSA is more complicated than you might think. In fact, depending upon the renovation project, it is possible to trigger full compliance with current codes without adding any additional square feet to the building.

AC Section 28-101.4.5 identifies the following exceptions to be excluded when determining the existing amount of FSA for calculating the 110% threshold:

• Square footage of floors removed during the course of the work when such floors are removed with supporting beams, joists, decking, and slabs on grade.
• Square footage of any floor installed with supporting beams, joists, decking, and slabs on grade within the 12 months preceding submission to DOB of construction documents for the proposed work. Such floors installed under a work permit signed off less than 12 months before such submission shall not be applied toward calculating existing FSA.

Owners of prior-code buildings who are planning a major alteration should take steps to ensure that the proposed work doesn’t inadvertently trigger full compliance with current codes.

If you have questions about how these requirements affect your specific property, please contact Metropolis Group at 212.233.6344.