What are the New Brunswick fire code requirements for an attached garage?

An attached garage in New Brunswick must have a minimum 45-minute fire-resistance-rated separation between the garage and the living space, including all common walls and any ceiling shared with rooms above. This fire separation is a life-safety requirement under the NB Building Code, and it is one of the most important — and most frequently botched — elements of attached garage construction.

The purpose of the fire separation is to give occupants time to escape the house if a fire starts in the garage. Garages contain vehicles with fuel, stored gasoline for lawn equipment, paints, solvents, propane tanks, and other flammable materials that make garage fires burn fast and hot. The 45-minute rating means the assembly must contain the fire and prevent flame and hot gas passage for at least 45 minutes under standard fire test conditions, giving the family time to wake up, evacuate, and call for help.

What the Fire Separation Assembly Requires

The most common way to achieve the required fire-resistance rating is to install 5/8-inch Type X fire-rated drywall on the garage side of every wall and ceiling that separates the garage from the house. Type X drywall contains glass fibres that hold it together longer under fire exposure than standard drywall. All joints must be taped and finished — leaving gaps, unsealed joints, or unfinished seams defeats the purpose of the assembly. In some configurations, particularly where the garage ceiling is directly below a bedroom, two layers of 5/8-inch Type X drywall may be required to achieve the necessary rating.

The door between the garage and the house is a critical component of the fire separation. The NB Building Code requires this door to be either a solid-core wood door at least 1-3/4 inches (44 mm) thick, or a door with a 20-minute fire-protection rating. The door must be equipped with a self-closing device — a spring hinge or hydraulic closer that pulls the door shut automatically. This ensures the door is not accidentally left open, which would completely bypass the fire separation. The door must also have proper weatherstripping to prevent smoke and gas migration. Importantly, the door between the garage and living space must never open directly into a bedroom — it must open into a hallway, kitchen, laundry room, or other non-sleeping area.

Every penetration through the fire-rated assembly must be properly fire-stopped. This includes electrical boxes, wiring, plumbing pipes, HVAC ducts, and any other service that passes through the common wall or ceiling. Approved fire-stop sealants, putty pads behind electrical boxes, and fire dampers in ducts are required to maintain the integrity of the assembly. A single unsealed penetration — even something as small as a cable TV wire — creates a pathway for flame and toxic gas to enter the living space.

Additional fire code considerations for attached garages in NB include these requirements. No heating equipment that uses an open flame or glowing element should be installed in the garage unless it is specifically designed and approved for garage use and is mounted at least 18 inches above the floor (to avoid ignition of heavier-than-air gasoline vapours). The garage floor should be sloped toward the overhead door or a floor drain to prevent fuel spills from pooling against the common wall. If the garage has a gas-fired heater or other fuel-burning appliance, a carbon monoxide detector is required in the adjacent living space, and one is strongly recommended inside the garage itself.

Insulation in the common wall between the garage and living space serves double duty — it contributes to both the fire-resistance rating and the thermal performance of the home's building envelope. Many builders in NB install R-20 batt insulation in the 2x6 common wall along with the Type X drywall, which satisfies both fire and energy code requirements simultaneously.

If you are adding an attached garage to an existing home, or if you suspect your current attached garage does not meet fire separation requirements, have a professional inspect the assembly. Common deficiencies in older NB homes include regular 1/2-inch drywall instead of 5/8-inch Type X, hollow-core doors without self-closers, unsealed electrical and plumbing penetrations, and missing drywall on the garage ceiling below second-storey rooms. These are not cosmetic issues — they are life-safety deficiencies that should be corrected. A qualified contractor familiar with NB Building Code fire separation requirements can assess your garage and recommend the necessary upgrades. Find garage contractors through the New Brunswick Construction Network at newbrunswickconstructionnetwork.com.