Zoning gets all the attention, but fire safety is what actually determines whether an ADU is possible. Under City of Yes, ADUs must still comply with New York State Residential Code, which has strict rules for fire separation, fire resistance and safe escape routes. These rules apply to all ADUs - internal, attached or detached.

Fire Separation Requirements

New York State code requires:

• Fire rated assemblies between the ADU and the primary dwelling for attached units.

• One hour fire rated walls and ceilings in most attached ADUs.

• Proper fire blocking around concealed spaces.

• Fire rated doors where required between dwelling units.

Egress and Fire Safety Requirements

• Every sleeping space needs a second means of egress.

• Basement ADUs require compliant egress window wells or exterior doors.

• Detached ADUs require safe paths to a public way.

• Smoke and carbon monoxide alarms must be interconnected.

• Heating and cooking appliances must meet combustion and ventilation standards.

Where Homeowners Run Into Trouble

• Semi attached homes lacking enough wall space for rated assemblies.

• Old garages with zero fire protection in walls or ceilings.

• Narrow side yards preventing compliant egress paths.

• Basement ceilings too low for required insulation and fire ratings.

Why This Matters for Staten Island and Brooklyn

Even if zoning allows an ADU, fire code may not.
You cannot “waive” fire separation.
You cannot “grandfather” unsafe structures.

Understanding fire safety early prevents expensive design changes.

—

Joseph Ranola | Five-Star Staten Island & South Brooklyn Realtor® (30 + Google reviews)
Associate Broker · Matias Real Estate | Founder · Bridge & Boro Team
Serving 103xx and 11209 / 11214 / 11228 | $25 M + closed volume
📞 917-716-1496 | ranolarealestate.com