N.Y. Real Property Law § 339-k: Certain work prohibited

§ 339-k. Certain work prohibited. No unit owner shall do any work

which would jeopardize the soundness or safety of the property, reduce

the value thereof or impair any easement or hereditament, nor may any

unit owner add any material structure or excavate any additional

basement or cellar, without in every such case the consent of all the

unit owners affected being first obtained.