6 Cortlandt Alley LLC is converting a 19th century commercial loft building into luxury condominiums. Located at 6 Cortlandt Alley (372 Broadway) in the Tribeca section of Manhattan, the 5-story building will have a two-story penthouse added to it. Although the proposed architectural plans would comply with the NYC building code, the developer wanted to improve the sound attenuation in the units. SEA was asked to review the ceiling/floor assemblies to confirm compliance with NYC requirements, as well as to consider ways to upgrade the acoustical properties of the proposed materials.
SEA identified the most common noise and vibration problems in condominiums with concrete floors as transmission through floor-ceilings due to: (1) airborne noise (e.g., speech, TV) through an intervening partition/floor into the adjacent space; and (2) footfall noise. The isolation of airborne noise is characterized by the Sound Transmission Class (STC) rating. The minimum code requirement is 50, but high quality construction would be 60 to 65. Impact noise reduction is measured by Impact Insulation Class (IIC) where the minimum code is 50, but high quality construction would be 70 to 75.
Noise and Vibration
- Evaluation of vendor claims and laboratory testing of STC and IIC values
- Discussions with vendors regarding testing claims and performance
- Recommendations regarding floor/ceiling assemblies that would meet the goals of high quality construction
Other projects involving review and recommendations for insulation of noise and vibration include Royal Palace banquet facility in Queens.