Can I add a second storey to only part of my bungalow in Ottawa?

Yes, adding a second storey over only part of a bungalow is a common approach, especially with post-war bungalows. A partial second storey can add meaningful living space without the full cost and disruption of raising the whole roof.

The first question is whether the existing foundation and walls can carry the extra load. Many older bungalows have poured concrete foundations, which is a good start, but a structural engineer needs to check the footing size, wall construction and concrete condition before design begins. If the foundation needs reinforcement, the engineer will specify underpinning or supplementary footings under the new section. On filled ground or sensitive clay, including Leda clay, the Ontario Building Code requires footing sizes to be engineered.

Your new storey has to meet the Ontario Building Code for structure, fire safety, exits and bedroom windows; your designer will confirm the details. For energy, an addition must meet a compliance package or the addition table, which for Zone 1 includes R-60 for a ceiling with an attic and R-19 + 5 ci for above-grade walls. You'll need a building permit from the City of Ottawa. The 2026 fee for additions is $12.75 per $1,000 of construction value, so a $150,000 valuation works out to about $1,913. Zoning review checks your height, lot coverage and setbacks, which can be tight on narrow lots.

A common layout puts the second storey over one section, often the back half above the bedrooms or living area, with the front staying single-storey under a new roofline. That creates an interesting profile and keeps costs more manageable. As perspective only, not a quote, partial second-storey projects can range from roughly $60,000 to $200,000 or more depending on size, structure, finishes, mechanical upgrades and whether you add a bathroom upstairs.

Mechanical systems need careful planning. A heat-loss calculation will show whether your furnace and ductwork can serve the new floor, and a separate zone with its own thermostat upstairs is worth discussing given Ottawa's cold winters and hot summers. Your electrician will tell you whether the electrical service needs upgrading; electrical work needs an ESA notification and is done by an electrical contractor licensed by ESA.

Ask contractors for itemized quotes that separate engineering, structure, mechanical and finishes. You can browse addition contractors in the Ottawa Construction Network directory at justynrookcontracting.com and compare quotes.

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

• Homeupgraders
• RenoMotion Inc.
• Diamond renovations
• BFI Renovations
• Joe Imerti Contracting