New York Lien Law § 34 provides that any contract, agreement or understanding waiving a right to file or enforce any lien is void as against public policy and wholly unenforceable. Rotodyne, Inc. v. Consolidated Edison Co. of New York, Inc., 85 Misc.2d 347, 378 N.Y.S. 899 (N.Y. Sup. 1975). However, rendering unenforceable a lien waiver is not to be applied retroactively. Michael Duff, Inc. v. Fair Housing Development Fund Corp., 56 A.D.2d 575 (2^nd Dep’t 1977). As such, Lien Law § 34 cannot be according retroactive effect to invalidate a waiver of lien provision contained in a previously executed contract prior to the implementation of § 34. Dickson Painting, Inc. v. Larry Walter, Inc., 55 A.D.2d 777 (3^rd Dep’t 1976).

However, under Lien Law § 34, a contractor, subcontractor, materialman or laborer may not waive its lien except by an express agreement in writing to that effect, and the intention to waive its right must be clear and unequivocal. C.H. Heist Ohio Corp. v. Bethlehem Steel Co., 20 A.D.2d 201 (4^th Dep’t 1964).  An agreement between an owner and contractor that not lien would be filed by the contractor or any subcontractor does not constitute an express agreement showing the intent of the subcontractor to waive its right to file a lien. Id. A subcontractor may forgo or waive its right to a mechanic’s lien by an express agreement in writing. Beacon Construction Co., Inc. v. Matco Electric Co., Inc., 521 F.2d 392 (2^nd Cir. 1975).

An express waiver of right to file a mechanic’s lien in a contract signed by a subcontractor in compliance with § 34 is binding and enforceable and will extinguish the right to file a notice of lien. Id. As such, a waiver of right to file a mechanic’s lien cannot be recalled or expunged. Id. A waiver will effectively prevent the foreclosure of a lien filed contrary to the provisions of a contract. J.B. Cieri Const. Co. v. Gramercy Const. Corp., 13 A.D.2d 901 (4^th Dep’t 1961).