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Canada
Attic conversion cost: turning an attic into a bedroom
Converting 30 m² of attic into a finished bedroom typically costs $55,000 before GST/HST, with most projects between $42,900 and $71,600. That includes permits and engineering, reinforced floor joists, insulation and drywall, a proper staircase, an egress window, a skylight, wiring and a ductless heat pump. A simpler finish is about $48,900; a higher-spec room with better insulation, hardwood and upgraded windows is around $63,300. Add a shed or gable dormer in the calculator if the roof is too low.
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mid-range, typicalCost by region
| Location | Basic | Mid-range | Premium |
|---|---|---|---|
| Quebec | $52,600 | $59,400 | $68,300 |
| Ontario | $49,000 | $55,300 | $63,600 |
| Alberta | $49,000 | $55,000 | $63,100 |
| British Columbia | $48,300 | $54,300 | $62,400 |
| Saskatchewan | $46,800 | $52,500 | $60,300 |
| Manitoba | $45,100 | $50,700 | $58,300 |
| Newfoundland and Labrador | $44,600 | $50,100 | $57,600 |
| Nova Scotia | $43,900 | $49,400 | $56,900 |
| New Brunswick | $43,200 | $48,700 | $56,100 |
What's included
Mid-range
- Building permit, drawings and structural engineer's review
- Reinforced floor joists, subfloor and sound insulation
- Insulation and air/vapour barrier under the roof, drywall and finish
- New staircase from the floor below, replacing the hatch
- Egress window in the gable wall
- Skylight, flashed into the roof
- New circuits, outlets, lighting and smoke alarms
- Ductless mini-split heat pump for heating and cooling
- Flooring, doors, trim and paint
What affects the cost
Headroom
Many 1920s to 1950s homes have attics tall enough to finish; many post-war bungalows and truss-roofed houses do not. If the room needs more height, a dormer or raising the roof becomes the main cost.
Insulation and ice dams
In a Canadian winter the roof above a heated attic must be insulated and air-sealed properly, with ventilation above the insulation where the design needs it. Poor detailing here causes frost, condensation and ice dams at the eaves.
Stairs
A code-compliant stair takes floor space on the level below. Where it lands, and what has to be reframed around it, is often the hardest design question in the whole project.
Dormers
A shed dormer adds the most usable floor space along the back of the house; a gable dormer suits a street-facing roof and heritage areas but adds less room for the money.
Asbestos and old insulation
Older attics often contain vermiculite insulation, which can contain asbestos. Have it tested before any demolition; professional removal is extra and not in our figures.
Heating and cooling
Attic rooms are the hottest in summer and coldest in winter. A ductless heat pump gives the room its own control and avoids overloading the existing ductwork.
How to save
- Have the attic measured and the insulation tested before paying for drawings.
- Keep the roof as it is if you already have the headroom; a dormer is the biggest single extra.
- Use a ductless heat pump instead of extending ducts from a basement furnace.
- Ask each contractor to price the stair, egress window and joist work separately so bids compare fairly.
Grants, tax and rules
Permits and licensed trades
Turning an attic into living space needs a building permit, and electrical, gas and plumbing work must be done by licensed trades, usually with their own permits and inspections.
GST/HST
GST/HST applies to renovation work. Our figures are before GST/HST (13% HST in Ontario, 5% GST in Alberta).
Frequently asked questions
How much does an attic conversion cost in Canada?
For about 30 m² of attic with a new stair, egress window, skylight, insulation, drywall and a mini-split, expect around $55,000 before GST/HST. A basic finish is about $48,900 and a higher-spec room around $63,300.
Do I need a permit to finish my attic?
Yes. Creating a bedroom or living space in an attic changes the use of the space and involves structure, stairs, insulation and electrical work, which all need a permit and inspections.
How much does a dormer add?
Choose a shed or gable dormer in the calculator to see the extra for your size. A gable dormer costs more per square foot of new space than a shed dormer.
Can every attic be converted?
No. Low-slope roofs, engineered trusses and very small attics may not give a usable room without major structural work. An engineer and a contractor can tell you after a site visit.
How long does it take?
Most attic conversions take two to three months of work after permits, longer with a dormer. Roof work is best done outside the coldest months.
How this estimate is calculated
Work hours: 333.6 · Labour: $30,364 · Materials: $24,681
Sources: Job Bank wages (Employment and Social Development Canada); Regione Toscana, Prezzario dei Lavori 2026 (CC BY 4.0); ECB exchange rates; market check: Attic bedroom ~320 sq ft without dormer, before GST/HST. RenoHouse Toronto attic conversion guide 2026 (cosmetic conversion without dormer $40-70k; shed dormer $15-30k; gable dormer $20-40k); RenoQuotes attic-to-bedroom guide (updated 6 Aug 2026: $150-300/sq ft); Homeyou Ontario ($40-100k).
Last reviewed September 26, 2026 · How we calculate costs · Editorial policy