Does the New Brunswick Building Code require a garage to have a firewall if attached to a house?

Yes, the New Brunswick Building Code absolutely requires fire separation between an attached garage and the living space of a house. This is a life-safety requirement, not an optional upgrade, and it applies to every attached garage in the province regardless of size, age, or whether the garage is heated or unheated. The purpose is to prevent a fire that starts in the garage — from a vehicle, stored flammables, or electrical fault — from rapidly spreading into the home where occupants may be sleeping.

The NB Building Code, which adopts and references the National Building Code of Canada, requires a minimum 45-minute fire-resistance rating on the wall and ceiling assemblies that separate the garage from the dwelling. In practical construction terms, this means the garage side of every shared wall and every shared ceiling must be covered with 5/8-inch Type X fire-rated drywall. This is not the same as standard 1/2-inch drywall — Type X drywall contains glass fibres that hold the gypsum core together longer under fire exposure, providing the required resistance time. All joints must be taped and finished (mud and tape at minimum — full Level 4 or 5 finishing is not required for fire performance, but the joints must be sealed). Some wall and ceiling assemblies may require two layers of drywall to achieve the 45-minute rating, depending on the framing spacing and insulation type — consult your building inspector or a qualified designer to confirm the specific assembly required for your project.

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 20-minute fire-rated door. Steel insulated exterior doors also meet this requirement. The door must be equipped with a self-closing device — a spring hinge or hydraulic closer that ensures the door returns to the closed position automatically. This is non-negotiable because an open door between the garage and the house completely defeats the fire separation. The door threshold and weatherstripping should also provide a seal against garage fumes, including carbon monoxide.

No direct openings are permitted between the garage and sleeping areas (bedrooms) unless the opening is protected by the required fire-rated assembly. In practice, this means the door from the garage typically enters a hallway, mudroom, or kitchen — never directly into a bedroom. Any windows in the common wall between the garage and house must also be fire-rated.

Every penetration through the fire separation must be properly fire-stopped. This includes electrical wires, plumbing pipes, HVAC ducts, gas lines, dryer vents, and any other service that passes through the shared wall or ceiling. Approved fire-stop sealants (typically red silicone caulk rated for fire-stopping) or mechanical fire-stop devices must be used at every penetration point. A single unsealed penetration — even a small hole for an electrical cable — compromises the entire fire separation and will fail inspection.

HVAC systems require special attention in attached garages. The garage must not share return air with the house — garage air containing carbon monoxide, gasoline vapours, and other contaminants must never be drawn into the home's heating system. If HVAC ducts pass through the garage, they must be sealed and fire-stopped where they penetrate the fire separation. A separate heating system for the garage (such as a unit heater) is the safest approach.

This is not an area for shortcuts or DIY interpretation. The fire separation between your attached garage and your home protects your family's lives while they sleep. Hire a professional contractor who understands NB Building Code fire separation requirements, and ensure your building inspector signs off on the assembly before it is covered by finishing materials. If you are adding an attached garage to your existing home or converting a breezeway into a garage connection, the fire separation requirements apply in full.

Need help finding a contractor experienced with attached garage construction in New Brunswick? New Brunswick Garages can match you with qualified builders through the New Brunswick Construction Network for free.