For structural work and construction that changes occupancy, landlords need permits from the New York City Department of Buildings. The law requires permits and inspections to protect against work that is not up to standards set by city codes. If your landlord tries to get around this, there are several ways you can use it to your advantage.
For example, if repairs are necessary in your apartment or the building, and the landlord is attempting to do unauthorized work that doesn't conform to code, it may pose a danger to tenants. Calling 311 to place a complaint can halt the work, require the landlord to obtain a permit, and adhere to established lawful standards with licensed workers.
If you are renting in a smaller property and the landlord wants to make alterations that would encroach upon rights afforded by your lease, lodging a complaint can stop construction activity.
Sometimes landlords subdivide rental units in ways that are illegal. Filing a complaint can prevent this and help to protect your rights.
Strategically, forcing the landlord to comply with requirements he or she may attempt to evade makes it more expensive to continue fighting with you. Still, you'll want to carefully evaluate whatever course of action you choose to pursue, because you may turn the landlord into an enemy. In that instance, if your lease is unregulated it may not be renewed. There's no guarantee that further court action after that will keep your tenancy intact.