What is the total cost of adding a master bedroom above my garage in Nepean?

Building a master bedroom above an attached garage gains real living space without expanding your home's footprint. There is no reliable Nepean-specific price for this project, because the cost depends mostly on what your existing garage can carry and what goes into the new room. As broad perspective only, a bedroom-over-garage addition can range from roughly $120,000 to $220,000 or more including structure, mechanical work and finishes. Treat that as perspective, not a quote.

The most important step is a structural assessment of the garage. Many garages were not designed to support a second storey. A structural engineer evaluates the garage footings, walls and roof framing and specifies what is needed, which might include widening or deepening footings, upgrading wall framing, or adding beams and posts. Until that assessment is done, nobody can price the project accurately.

Foundations deserve particular attention. On clay or poorly defined soils, the Building Code calls for footings at least 1.2 m deep and not less than the depth of frost penetration, and garage footings are not always built to carry a house-level load. If yours need upgrading, the engineer designs the fix, and the City reviews it through the permit process.

The cost drivers to ask about:

• Framing, roof and exterior. Matching the new storey's cladding and roofline to the existing house matters for appearance and value.
• The garage ceiling. The floor between a garage and a bedroom needs to be built to keep exhaust fumes out of the living space; your designer will specify the assembly.
• Insulation. A room over an unheated garage needs a well-insulated, well-sealed floor or it will feel cold in winters that regularly reach well below -20°C.
• Mechanical systems. Ask for a heat-loss calculation to decide between extending ductwork and a separate ductless heat pump. Electrical work needs an ESA notification and is done by an ESA-licensed electrical contractor. An ensuite adds plumbing, venting and tiling; plumbers are a compulsory trade you can check on the Skilled Trades Ontario Public Register.
• Finishes. Flooring, closets and trim can move the total considerably.

The building permit fee is $12.75 per $1,000 of construction value (minimum $117), so a $160,000 valuation would be about $2,040. Drawings and engineering are separate.

Ask each contractor for an itemized quote that separates structural work from finishes, so you can see where the money goes. You can browse addition contractors in the Ottawa Construction Network directory at justynrookcontracting.com and compare.

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• RenoMotion Inc.
• Humble Homes - property maintenance
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