How much should I budget for a single-car attached garage in Saint John New Brunswick?

You should budget between $35,000 and $55,000 for a single-car attached garage in Saint John, NB, with the typical project landing around $40,000 to $48,000 for a standard 12x20 to 14x24 footprint. Attached garages cost more per square foot than detached garages because they require fire-rated assemblies, integration with your existing roof and foundation, and more complex framing where the new structure connects to the house.

The fire separation requirement is a significant cost factor unique to attached garages. The NB Building Code mandates a minimum 45-minute fire-resistance rating on the wall and ceiling assembly separating the garage from the living space. This means 5/8-inch Type X fire-rated drywall on the garage side of all common walls and ceilings, with all joints taped and finished. The door between the garage and the house must be a solid-core door (minimum 1-3/4 inches thick) or a 20-minute fire-rated door with a self-closing mechanism. These requirements add $2,000 to $4,000 to the project compared to a detached garage of the same size, but they are non-negotiable life-safety features.

The foundation for an attached garage in Saint John must extend below the frost line — 4 to 5 feet below grade — and must be properly tied into or isolated from the existing house foundation. Saint John's rocky terrain can complicate excavation, and many properties in the older neighbourhoods have challenging site conditions including slopes, limited access, and proximity to neighbouring structures. Foundation costs for an attached single-car garage typically run $6,000 to $12,000 including excavation, forming, concrete, and waterproofing. If rock excavation is required, expect to add $2,000 to $5,000 depending on the volume and hardness of the rock.

Saint John's coastal Maritime climate adds specific considerations that affect your budget. The city experiences persistent wind off the Bay of Fundy that increases uplift forces on the garage roof, potentially requiring additional hurricane straps and heavier sheathing. Driving rain is common, so the weather-resistive barrier and flashing details where the new garage roof meets the existing house wall are critical — improper integration at this junction is the number one source of leaks in attached garage additions. Budget $1,000 to $2,000 for proper step flashing, counter-flashing, and ice-and-water shield membrane at the roof-to-wall connection.

The roof integration is often the most complex part of an attached garage project. Matching the existing roof pitch, tying into the existing drainage pattern, and ensuring the connection does not create a snow drift accumulation zone all require experienced framing and roofing work. In Saint John's climate, where snow loads range from 2.4 to 4.8 kPa, the area where the garage roof meets the house wall can accumulate drifted snow at two to three times the ground snow load. The roof structure in this zone must be engineered accordingly.

Here is how the budget typically breaks down for a single-car attached garage in Saint John: foundation and slab ($6,000 to $12,000), framing including roof tie-in ($8,000 to $14,000), roofing ($2,500 to $5,000), siding to match the existing house ($2,000 to $5,000), fire separation assemblies ($2,000 to $4,000), one overhead door with opener ($1,500 to $3,000), electrical ($1,500 to $3,000), and finishing details including trim, grading, and cleanup ($2,000 to $4,000).

A building permit is required for all attached garage construction in Saint John, and you will also need an electrical permit for the garage wiring. Setback requirements for attached garages follow the same rules as the main dwelling — typically 15 to 25 feet from the front property line and 5 to 10 feet from side lines, depending on the zoning. Many Saint John lots, particularly in the older parts of the city, are narrow, which can limit where an attached garage can be positioned. Obtain a property survey before finalizing your design to avoid costly setback violations.

For a project of this complexity, hiring a professional is strongly recommended. An attached garage involves foundation work, structural framing, fire separation, roof integration, and electrical — all areas where mistakes are expensive to fix and where code compliance is critical. Get at least three quotes from experienced local contractors, and confirm that each contractor carries liability insurance and WorkSafeNB coverage. New Brunswick Garages can match you with garage contractors for free estimates through the New Brunswick Construction Network.