basement cost guide
How much does it cost to finish a basement?
Finishing a basement costs $40,000–$80,000 for a standard 1,000 sqft space. Full basement apartments with kitchens, bathrooms, and separate entries run $75,000–$140,000.
Key Takeaways
- •Standard finish (1,000 sqft): $40,000–$80,000
- •Basement apartment with kitchen + bath: $75,000–$140,000
- •Underpinning (lower the floor) adds $50,000–$120,000
- •Egress windows required for legal bedrooms
Cost Breakdown
| Line item | Typical share / cost |
|---|---|
| Framing & insulation | 15–20% ($6,000–$16,000) |
| Drywall & paint | 10–15% ($4,000–$12,000) |
| Electrical (rough-in + finish) | 10–15% ($4,000–$12,000) |
| Plumbing (if bath/kitchen) | 10–20% ($4,000–$16,000) |
| HVAC modifications | 5–10% ($2,000–$8,000) |
| Flooring | 8–12% ($3,200–$9,600) |
| Bathroom (if added) | $10,000–$22,000 add |
| Egress window (per opening) | $3,500–$7,000 add |
Factors That Affect Your Cost
Ceiling height
Below code minimum (6'5" Canada / 6'8" US for habitable rooms) requires underpinning.
Moisture
Waterproofing or sump systems may add $3,000–$15,000 before finishing.
Legal basement apartment
Requires fire separation, egress, and separate HVAC zoning. Adds 20–35% to base cost.
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Related Questions
Do I need a permit to finish my basement?
Yes — most jurisdictions require permits for framing, electrical, plumbing, and any HVAC changes in a basement finish.
How long does basement finishing take?
Typical timeline is 6–12 weeks for a standard finish. Adding a legal apartment with kitchen/bath stretches to 14–20 weeks.