Can I add a room over my attached garage in Ottawa?

Often, yes. A room over an attached garage can be an efficient way to add space because the footprint already exists, but the structure is the big question. A garage was built to carry a roof, not a habitable room, so you need to know whether its foundation and walls can take the extra load.

A structural engineer should assess the existing garage foundation, walls and framing before you design. Garage foundations vary, and their footings may only have been sized for a light structure. Under the Code, footings on clay or soils that are not clearly defined must be at least 1.2 m deep and not less than the depth of frost penetration, and on sensitive clay, including Leda clay, footing sizes must be engineered. If reinforcement is needed, the engineer will specify it. Ask for a written fee quote for the assessment and an itemized structural line in contractor quotes.

The floor between the garage and the new room is the most important detail. The Building Code requires the separation between an attached garage and the living space to protect occupants from fire and from vehicle exhaust, so the assembly has to be built and sealed to the standard your designer specifies. That includes sealing every penetration for wiring, plumbing and ducts, and keeping the house's heating and return air separate from the garage. Your designer confirms the exact assembly and the City checks it at inspection.

Insulating a floor over an unheated garage takes care, because the room sits above a cold space. Ask how your contractor will insulate and air-seal the floor so the room doesn't feel cold underfoot. Energy rules apply; the Code's addition table calls for R-60 in an attic ceiling and R-19 plus R-5 continuous insulation in above-grade walls unless a compliance package is used. A carbon monoxide alarm in the new space is a sensible safeguard; ask your designer what the Code requires.

Cost depends on size, structural work and finishes, so treat any figure as perspective and ask for itemized quotes.

A building permit is required; the application needs drawings and structural information. Fees for additions are $12.75 per $1,000 of construction value, minimum $117, and the City can tell you current review times. Electrical work needs an ESA notification or permit, and gas work is done by a TSSA-certified gas technician. Ask each contractor whether they have WSIB coverage or are exempt, and get warranty terms in writing. You can browse addition contractors in the Ottawa Construction Network directory and compare quotes.

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Looking for experienced contractors? The Ottawa Construction Network connects homeowners with qualified professionals:

• 613Bins
• RenoMotion Inc.
• Somar Contracting Inc.
• ALM Construction & Landscaping Inc.
• Leeds Property Maintenance