How much does it cost to renovate a duplex in Saint John NB?

Renovating a duplex in Saint John runs anywhere from $80,000 to $400,000+ depending on scope, condition, and how much of each unit you're touching — and Saint John's older housing stock means hidden surprises are more the rule than the exception.

The wide range exists because "renovate a duplex" covers a lot of ground. A cosmetic refresh of both units — new paint, flooring, fixtures, and appliances — might run $40,000-$75,000 total across both units. A mid-range renovation of both units (kitchens, bathrooms, flooring, windows, lighting) lands in the $100,000-$180,000 range. A full gut renovation of a duplex — stripping both units to the studs, upgrading electrical panels, replacing plumbing stacks, new insulation, new windows, new kitchens and bathrooms — can easily reach $250,000-$400,000 or more, particularly in Saint John's older Victorian and Edwardian-era homes where the building envelope and mechanical systems are long overdue for replacement.

Saint John's Housing Stock Changes the Math

Saint John has one of the oldest housing inventories in Atlantic Canada. Many duplexes in the South End, North End, and West Side were built between 1880 and 1940, which means you're almost certainly dealing with knob-and-tube or early aluminum wiring, cast iron or galvanized steel drain stacks, minimal or no insulation in wall cavities, single-pane windows, and potentially asbestos in floor tiles, pipe insulation, or ceiling texture coatings. Any pre-1990 Saint John duplex should be assessed for asbestos before demolition work begins — professional abatement adds $3,000-$15,000 to the project depending on what's found, but it's legally required and non-negotiable.

The Bay of Fundy's persistent fog, wind-driven rain, and salt air are hard on Saint John exteriors. If the duplex hasn't had exterior work in the last 15-20 years, budget for siding replacement ($12,000-$25,000 for a typical duplex), window replacement ($10,000-$20,000 for both units), and potentially foundation repointing or parging on older stone or brick foundations. These aren't optional upgrades — they're moisture management, and skipping them while finishing interiors is a recipe for mould within a few years.

Breaking Down the Key Cost Categories

Electrical is often the biggest surprise in older Saint John duplexes. Upgrading two units from 60-amp knob-and-tube to modern 200-amp service with proper panel and wiring throughout runs $15,000-$30,000 for both units. This is TSANB-licensed work with mandatory inspection — no shortcuts here.

Plumbing in a duplex renovation typically involves replacing the main stack, updating supply lines to copper or PEX, and roughing in for any bathroom or kitchen changes. Budget $8,000-$20,000 depending on how much is being relocated or replaced.

Kitchens at a mid-range level run $25,000-$50,000 per unit, so both kitchens together could be $50,000-$100,000. Bathrooms at mid-range run $15,000-$30,000 each.

Insulation upgrades are worth prioritizing in any Saint John duplex renovation. Blown-in insulation to wall cavities and attic top-up to R-50+ dramatically reduces heating costs — important in a province where heating bills are a major operating cost for rental properties. Budget $8,000-$18,000 for a full insulation upgrade on a typical duplex.

Practical Tips for Duplex Renovations

Plan for a 20-25% contingency on any Saint John duplex renovation — older homes in this city reliably produce surprises once walls open up. Stagger the renovation unit by unit if the property is tenanted, which adds time but preserves rental income during the project. Pull all required permits through the City of Saint John's building inspection department — unpermitted work on a rental property creates serious complications with insurance and at resale.

Get a minimum of three detailed quotes from contractors experienced with multi-unit residential work. Scope must be identical across quotes — compare line by line, not just the bottom number. The lowest bid on a Saint John duplex renovation is almost never the right choice.

Need help finding experienced renovation contractors in Saint John? New Brunswick Renovations can connect you with local professionals at no cost — get in touch to get started.