Do I Need a Permit to Finish My Basement in Montana?
Quick Answer
Yes — any framing, electrical, plumbing, or mechanical work requires a permit.
What Requires a Permit
Framing walls, adding electrical circuits, installing plumbing, and modifying HVAC in a basement all require a building permit. Cosmetic work — painting, laying floating floors over existing concrete, and adding furniture — does not.
Egress Windows Are Non-Negotiable
Every basement bedroom must have an egress window: minimum 5.7 sq ft net clear opening, sill no higher than 44 inches above the floor (the IRC standard most jurisdictions follow). Window wells deeper than 44 inches need a permanently attached ladder or steps. This is a life-safety requirement — inspectors will not pass a basement without proper egress.
The Four Inspections
Expect four inspections: framing (walls, fire blocking, egress openings), MEP rough-in (electrical, plumbing, HVAC before walls are closed), insulation (exterior walls, vapor barrier), and final (drywall, fixtures, smoke/CO detectors). Do not close walls before passing framing and rough-in inspections.
Common Mistakes
Enclosing the furnace room without combustion air supply, skipping egress windows in bedrooms, not adding enough electrical circuits (you'll want dedicated circuits for the bathroom and any kitchen/wet bar), and forgetting smoke detectors in every bedroom and outside sleeping areas.
Bottom Line
Yes, you need a permit. The biggest requirement is egress windows for bedrooms. Budget 4 inspections and don't close walls before passing rough-in.
Permit fees by city in Montana
Verified from each city’s published fee schedule. Where a city has no separate fee listed for this project, open the city page for the current requirements and amount.
| City | Permit fee | Source |
|---|---|---|
| Anaconda-Deer Lodge | $12.50Verifiedvia Residential Building Permit (New Construction) | Residential Building Permit (New Construction) → |
| Billings | $30.00Verifiedvia Residential Building Permit (New Construction) | Residential Building Permit (New Construction) → |
| Bozeman | (Administrative Charges/Employee/Hour + Inspector's Hourly Pay Rate) x Table A factor (amount of inspection time per sq ft, by construction type and fire rating) x Building Square FootageVerifiedvia Residential New Construction Permit | Residential New Construction Permit → |
| Butte-Silver Bow | $75.00 per hour, one-hour minimumVerifiedvia New Residential Construction Permit | New Residential Construction Permit → |
| Great Falls | Ranges from $62.61 (value $1-$1,000) up to $710.45 (value $49,001-$50,000), per the $1,000-increment table in Exhibit AVerifiedvia Residential Building Permit (New Construction) | Residential Building Permit (New Construction) → |
| Havre | $23.50Verifiedvia Residential Building Permit (New Construction / Addition / Remodel) | Residential Building Permit (New Construction / Addition / Remodel) → |
| Helena | $22.00Verifiedvia Residential Building Permit (One- and Two-Family Dwelling — New Construction) | Residential Building Permit (One- and Two-Family Dwelling — New Construction) → |
| Kalispell | $23.50Verifiedvia Residential Building Permit (New Construction) | Residential Building Permit (New Construction) → |
| Missoula | $36 permit fee + $11.00 plan review feeVerifiedvia Residential Building Permit (New Construction) | Residential Building Permit (New Construction) → |
| Unincorporated Yellowstone County | Calculated based on project valuation (fee schedule not published inline on the application; contact Building Codes Bureau at (406) 841-2056 for the current valuation-based fee table)Verifiedvia Residential Building Permit | Residential Building Permit → |