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Court Clarifies Law Governing Party Walls and Property Lines

Building development is rampant in Manhattan, often including developers buying old buildings from the turn of the last century and ripping them down.  However, adjoining buildings from that era often share what is called a “party wall.”  This means that a single wall between the two buildings held up both of them when they were first constructed and for many years thereafter. What happens when the owner of one of the buildings decides to demolish its building?  The old building will be torn down and a new building constructed in its place, including a new wall that does not utilize the party wall for support.  But if the new building is taller than the old one, which it usually will be, then once the new building reaches the top of the party wall, the new structural wall often will be designed to “jog” a few inches over the top of the party wall toward the property line, and build up from there without again touching the party wall.

A recent court case raised the question whether this common practice is permissible. After a developer had constructed its new building incorporating the space above the party wall on its side of the property line, the adjoining owner sued, claiming that it had the right to use the entire width of the party wall to support an addition it would like to add on top of its existing building, which the defendant’s new construction allegedly blocked it from doing.

In 145 W. 21st Realty LLC v. First West 21st Street LLC, Index No. 653241/2012, NYLJ 1202792788020, 2017 NYLJ LEXIS 1795 (Sup. Ct. N.Y. Co. June 26, 2017), the court rejected the adjoining owner’s claims for encroachment, trespass, and negligence.  It held that since the developer “has not built on or carried up the party wall, and certainly has not crossed the property line,” its conduct was proper.  Moreover, “while plaintiff complains that defendant’s construction will make its own upward expansion more expensive, because it can no longer extend the full width of the existing party wall upwards, what plaintiff is contemplating would be a trespass upon some or all of defendant’s side of the property line….”  Ganfer Shore Leeds & Zauderer, LLP represents the successful developer-defendant in this case.