Certificate of Appropriateness (C of A)

N.Y.C. Admin. Code § 25-305; § 25-307; § 25-308

Under the NYC Landmarks Law, it is unlawful to alter, reconstruct, or demolish any improvement on a landmark site, in a historic district, or containing an interior landmark unless the Landmarks Preservation Commission has issued a Certificate of Appropriateness (or a certificate of no effect / notice to proceed); this requirement is set by § 25-305. Section 25-307 establishes the factors the Commission must weigh (effects on the protected exterior or interior architectural features and, for historic-district work, the relationship to neighboring improvements and consistency with the chapter's preservation purposes), and § 25-308 governs the public-hearing review procedure (a hearing on each request, with a determination generally within 90 days). The Commission's guidance treats significant work such as rooftop or rear-yard additions, new construction, demolition, and alteration or removal of features like stoops and cornices as requiring a Certificate of Appropriateness.