How much does it cost to build a legal secondary rental suite in a basement in Fredericton including a separate entrance?

A legal secondary rental suite in a Fredericton basement with a separate entrance typically costs $60,000 to $100,000 or more, depending on the size of the space, the condition of the existing foundation, and the level of finish. This is at the higher end of basement renovation projects because it involves waterproofing, structural work for the separate entrance, full plumbing and electrical rough-ins, fire separation, and code-compliant finishing throughout.

The separate entrance is often the single most expensive component beyond the basic finishing. Creating an exterior entrance to a basement requires excavating alongside the foundation, cutting an opening through the foundation wall (or enlarging an existing window opening), installing a pre-hung exterior door with proper weatherproofing, building a stairwell with code-compliant railings and treads, and installing a retaining wall system or concrete stair well with drainage. In Fredericton, where the Saint John River valley produces mixed clay and loam soils with seasonal high water tables, this excavation and drainage work must be done carefully. Budget $8,000 to $20,000 for the separate entrance alone, including structural engineering, foundation cutting, the stairwell, door, and waterproofing around the new opening. An engineer's stamp is required because you are modifying a load-bearing foundation wall.

Here is a realistic cost breakdown for a Fredericton basement suite of approximately 700 to 900 square feet:

Waterproofing is step one — never finish a rental suite without addressing moisture. An interior drainage system with sump pump runs $3,000 to $8,000. Given Fredericton's proximity to the river and seasonal flooding risk in low-lying neighbourhoods, a battery backup sump pump ($500 to $1,000 additional) is strongly recommended. Insulation with 2-inch rigid foam or closed-cell spray foam costs $5,000 to $12,000 for the full perimeter. Framing and drywall including 1-hour fire-rated Type X ceiling costs $10,000 to $18,000. Electrical rough-in with a sub-panel, GFCI outlets throughout, AFCI bedroom circuits, interconnected smoke and CO detectors runs $3,000 to $6,000. Plumbing for a full bathroom and kitchenette including breaking and patching the concrete slab is $5,000 to $12,000. Egress windows for each bedroom at $2,500 to $5,000 each. Flooring with Dricore subfloor panels and LVP on top runs $5,000 to $10,000. The kitchen or kitchenette with cabinets, countertop, sink, and appliances adds $5,000 to $15,000. Finishing touches like interior doors, trim, paint, and lighting bring another $3,000 to $6,000.

Permits in Fredericton are handled through the city's building inspection department, and you will need building, electrical, and plumbing permits. Expect $200 to $400 in permit fees and multiple inspections: framing, insulation, rough-in electrical and plumbing, fire separation, and final. The City of Fredericton requires that secondary suites comply with zoning regulations — confirm your property qualifies before investing in design work.

Two Fredericton-specific factors affect your budget. First, radon testing is essential before sealing up a rental unit — elevated radon levels are found in many parts of the Fredericton area, and mitigation ($2,000 to $4,000) is far easier to install before finishing. Second, many older Fredericton homes have low basement ceilings that may not meet the 6-foot-5-inch minimum for habitable space. If headroom is insufficient, the project may require underpinning, which can add $30,000 to $80,000 and is a separate project altogether. Get 3 or more quotes from experienced basement contractors — pricing in the NB market varies 30 to 40 percent between contractors for identical scope.

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

• Thirty Four Renovations
• Gionetterenovations