Illegal Building Enforcement: Violations and Penalties

Any new construction, significant renovation, or substantial expansion carried out without officially approved permits from the DOB is considered an immediate, illegal act. For instance, building unauthorized rooftop structures, extending a balcony, or converting a garage into a legal living unit without obtaining DOB authorization can swiftly lead to enforcement actions. This category also includes substantial structural changes like adding or removing load-bearing walls, which pose a direct safety threat to the occupants and the public.

Using a residential property for unauthorized commercial activity, or converting legally defined single-family dwellings into multi-family residences without proper authorization, constitutes a clear violation of zoning laws. This type of illegal use or occupancy often involves altering the number of units beyond what is legally allowed by the Certificate of Occupancy (CO). Such unauthorized conversions, particularly illegal cellar or attic apartments, can trigger severe penalties including vacate orders and fines from both the DOB and the Department of Housing Preservation and Development (HPD).

A Stop Work Order (SWO) is a critical enforcement tool that immediately halts all construction or alteration activities on a site due to safety risks or verified illegal work. Issued by DOB inspectors upon discovery of a violation, SWOs remain strictly in effect until all violations are formally resolved and a resumption of work is officially authorized by the Department. Furthermore, if the illegal work fundamentally compromises the structural integrity or fire protection systems of a building, the DOB may issue a Vacate Order. This requires the immediate, mandatory evacuation of the premises and is often enforced on-site with the assistance of the NYPD.

The majority of illegal construction matters ultimately result in DOB-issued violations that are adjudicated at a hearing before the Office of Administrative Trials and Hearings (OATH), formerly known as the Environmental Control Board (ECB). Civil penalties can range widely, from a base fine of $500 to over $25,000 per violation, depending heavily on the violation's classification: Class 1 (Immediately Hazardous), Class 2 (Major), or Class 3 (Lesser). Crucially, certain Class 1 violations—particularly illegal conversions—can trigger substantial ongoing daily penalties until the condition is officially corrected and certified.

The most common and definitive remedy for an illegal alteration is to formally file for post-approval of the unpermitted work through a qualified professional architect or engineer. This process involves submitting existing conditions and proposed plans to legalize the structure to current code standards, a procedure often referred to as "Legalizing As-Built Work." If the work cannot be brought into compliance with current building codes or zoning regulations, the required remedy will be the full physical removal of the illegal construction and restoration of the premises to its original, legally compliant condition. A Certificate of Correction must then be filed and accepted by the DOB to clear the violation.

Property owners are entitled to dispute the factual basis or legal merit of a violation at an administrative hearing before the Office of Administrative Trials and Hearings (OATH). Success in contesting a violation largely depends on presenting comprehensive documentation, a favorable compliance history, and a strong legal argument based on code interpretation. To effectively halt the accrual of significant daily fines—such as those imposed for illegal occupancy under $28-201.1 of the NYC Administrative Code—owners must promptly file a Certificate of Correction with the DOB and ensure it is formally accepted by the Department. Without this official acceptance, the penalties will continue to accrue daily, potentially amounting to tens of thousands of dollars.