How much does a two-storey addition cost in Barrhaven?

A two-storey addition can add a lot of living space on a relatively small footprint. There is no reliable Barrhaven-specific price for this kind of project; what you pay depends on your lot, your soil, the size of each floor and your finishes. As broad perspective only, a two-storey addition can range from roughly $200,000 to $400,000 or more. Treat that as perspective, not a quote.

The cost drivers that apply in Barrhaven apply anywhere in Ottawa:

• Soil and foundation. Parts of the region have clay soils, and the Building Code requires footing sizes on sensitive clay to be engineered. On clay or poorly defined soils, footings must be at least 1.2 m deep and not less than the depth of frost penetration. Your engineer may want a geotechnical investigation before designing the foundation.
• Structure. Two storeys mean heavier loads and more complex framing, stairs and roof tie-ins.
• Mechanical systems. Extending heating, ventilation, plumbing and electrical to two new floors is significant. Ask for a heat-loss calculation to see whether your existing furnace can carry the extra load or whether a separate system makes more sense. Electrical work needs an ESA notification and is done by an ESA-licensed electrical contractor.
• Envelope. In winters that regularly reach well below -20°C, insulation, air sealing and window quality drive comfort and running costs. An addition must meet the Code's energy requirements through a compliance package or the addition table.
• Finishes. Flooring, millwork and fixtures can move the total substantially.

Zoning sets maximum height, lot coverage and setbacks, so check your property's zone before design. Ottawa currently has two zoning by-laws in effect while appeals are resolved. If you need relief, a minor variance application to the Committee of Adjustment costs $3,759 for an urban property in 2026.

The building permit fee is $12.75 per $1,000 of construction value (minimum $117); a $300,000 valuation would be about $3,825. Drawings and engineering are separate. Ask the City for current approval timelines.

Hold a contingency for surprises once the existing walls are opened. When interviewing contractors, ask whether they have WSIB coverage or are exempt, ask for a certificate of liability insurance, and ask for references from multi-storey additions they have built. You can browse addition contractors in the Ottawa Construction Network directory at justynrookcontracting.com and compare itemized quotes.

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