He can’t do that, can he? Well, yes he can sometimes, although never permanently. But the good news is, he has to pay you and probably your lawyer too.
This is New York City, after all. Sometimes—in fact lots of times— the only way that one property owner can work on his building is to set up on the adjoining property. Therefore, the law in New York (RPAPL § 881) says if the only reasonable way that your neighbor can work on his building is to temporarily use part of your property, you can’t stop him. But he can’t damage your property or permanently alter it or take longer than necessary—and a judge can order him to pay you (and probably your lawyer) for his trouble, usually including a monthly fee until he’s finished. The amount will be set by the judge if you, and the neighbor can’t agree. One way or another, though, you may have to let your neighbor work on his building from your property. At least you’ll get paid.
If you have problems with your real estate in New York, call Andrew Weltchek.
From the desk of Andrew Weltchek 