In Laval, a standard-quality basement renovation runs $26,255 to $60,965, prices below the Canadian average (index 89). A budget version starts around $18,379 and premium work reaches $97,544.
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| Line item | Range | Share |
|---|---|---|
| Framing, Drywall, Insulation & Ceiling | $4,984 – $13,706 | 31 % |
| Flooring | $1,869 – $4,361 | 10 % |
| Bathroom | $4,984 – $11,214 | 27 % |
| Kitchen | $4,984 – $9,968 | 24 % |
| Electrical | $1,558 – $3,427 | 8 % |
Included
Not included
| Line item | Range | Share |
|---|---|---|
| Framing, Drywall, Insulation & Ceiling | $7,120 – $19,580 | 31 % |
| Flooring | $2,670 – $6,230 | 10 % |
| Bathroom | $7,120 – $16,020 | 27 % |
| Kitchen | $7,120 – $14,240 | 24 % |
| Electrical | $2,225 – $4,895 | 8 % |
Included
Not included
| Line item | Range | Share |
|---|---|---|
| Framing, Drywall, Insulation & Ceiling | $11,392 – $31,328 | 31 % |
| Flooring | $4,272 – $9,968 | 10 % |
| Bathroom | $11,392 – $25,632 | 27 % |
| Kitchen | $11,392 – $22,784 | 24 % |
| Electrical | $3,560 – $7,832 | 8 % |
Included
Not included
In Laval, Quebec, a standard-quality basement renovation typically costs between $26,255 and $60,965 in 2026 — prices are below the Canadian average, with a local cost index of 89%. Expect around 6 to 12 weeks of work and a 50–75% return on investment at resale. Exterior foundation insulation plus an interior sub-slab vapour break is the gold standard here — ice-damming at the rim joist is the most common retrofit failure.
Same job in Montreal: $27,435 – $63,705 at standard quality, about 4 % more expensive than Laval on our cost index.
Laval basements sit in the Rivière des Prairies floodplain, and the city treats sewer backup as the owner’s problem to prevent: the check valve required by bylaw L-11870 goes in before the floor does. Most of the housing stock is post-1960 bungalows and split-levels whose basements were poured with usable ceiling height, so underpinning is rarely the question here; humidity and insulation are. Finishing the existing space needs no permit, adding a bedroom, a bathroom or a separate dwelling does, and an intergenerational unit also depends on your lot’s zoning. Rénoclimat can cover insulation and air sealing if an energy advisor evaluates the house before the work.
Authority: Ville de Laval, "Trouver mon permis"
Guide: Renovating in Québec: licences, taxes, permits and programs (2026)
Before any basement finishing work, address moisture issues first — this is non-negotiable in Canada. Have a professional assess the foundation for cracks, water infiltration, and radon levels. Basement ceiling height determines your options: 7 feet minimum is required by building code for habitable space. Plan electrical and plumbing rough-ins for a future bathroom even if you're not building one now ($500–$1,000 upfront saves $3,000–$5,000 later).
Waterproofing and moisture mitigation ($2,000–$8,000) is the largest variable cost. Egress windows are required by code for bedrooms and typically cost $2,500–$5,000 each installed. Underpinning (lowering the floor) costs $30,000–$70,000 but creates significant value in homes with low basements.
Pro tip
Install a sump pump with battery backup before finishing your basement — even if you've never had water issues. One flood can destroy $20,000+ of finished basement, and climate change is increasing urban flooding across Canada.
Laval's housing is mostly post-1960 bungalows, split-levels and early condos now on their first or second full renovation. RBQ-licensed contractors based in Laval and on the North Shore serve it, and on our cost index Laval sits a notch below Montréal.
Laval shares Montréal's cold winters and humid summers. Its flat terrain along the Rivière des Prairies makes some sectors prone to spring flooding and sewer backup, which is why the city requires a backwater valve and why a basement project starts with drainage.
Our 2026 estimate for a standard-quality finished basement in Laval is $26,255 to $60,965, from about $18,379 for a budget finish to $97,544 with a bathroom, built-ins and heated floors. The range moves with the size of the space and with whether plumbing is added.
Only when the number of rooms or the structure changes, according to the city’s permit table: adding a bedroom, a bathroom or a dwelling needs a permit, refinishing the existing space does not. The permit costs $92 for the first $20,000 of work plus $2.50 per further $1,000.
Yes. Bylaw L-11870 requires safety devices including a check valve on the building’s sewer connection, and the city declines liability for backup damage in a home without one. Have it checked or installed before you finish the floor: it goes in the drain line, under the slab.
Flooring is one line of the estimate above; open the Standard panel to see its share. Vinyl plank is the usual choice below grade because it tolerates humidity; engineered wood needs a dry, insulated subfloor first.
Both need a permit from the city, and a separate dwelling also depends on the zoning of your lot. Check with the Service de l’urbanisme before pricing the work; a legal unit is a different project from a finished basement, with egress, fire separation and sound requirements.
Insulation and air sealing are covered by Rénoclimat after an energy advisor evaluates the home, before and after the work. Book the evaluation before the contractor starts, or the work will not qualify.
Complete guide
Read our complete national guide to basement costs