Permits you need to finish a basement in Denver

If you’re finishing a basement in Denver, you need permits. There is no exception for “small projects” or “I’ll just do the framing myself.” The city has a basement-finish-specific application path, and they enforce it.

Here is exactly what’s required, what we handle on your behalf, and what to expect.

The permits you actually need

A basement finish in the City and County of Denver typically requires:

1. Building permit — for any framing, drywall, or new walls
2. Electrical permit — for any new circuits, outlets, or fixtures
3. Plumbing permit — if you’re adding a bathroom or kitchenette
4. Mechanical permit — if you’re modifying HVAC ductwork or adding a furnace
5. Sewage permit — if a new bathroom requires connection to the main line

For a typical basement finish with a new bathroom and bedroom, you’ll need all five. We bundle them and submit together.

What it costs

Permit fees in Denver scale with project value:

• $25,000 project: roughly $400–$700 in permits
• $75,000 project: roughly $1,000–$1,800
• $150,000 project: roughly $2,000–$3,500

We include all permitting in our fixed-price proposal, so you don’t write a separate check.

How long it takes

Denver’s residential permit review currently runs 2–4 weeks for a basement finish. Surrounding municipalities vary:

• Lakewood, Wheat Ridge: 3–5 weeks
• Aurora: 4–6 weeks
• Cherry Hills Village: 4–6 weeks (its own municipality)
• Boulder: 4–8 weeks
• Englewood: 2–4 weeks
• Centennial: 3–5 weeks

We submit on day one of the project schedule and build framing only after issuance.

The code requirements that catch homeowners off-guard

Egress windows

If you’re adding a bedroom (anywhere someone might sleep), you need a code-compliant egress window:

• 5.7 sq ft minimum opening
• Minimum 24” tall, 20” wide
• Sill no more than 44” above the floor
• A window well of at least 9 sq ft if below grade
• Permanent ladder or steps if the well is deeper than 44”

We cut, install, waterproof, and pass inspection. Cost typically $3,500–$6,000 per egress, depending on whether we’re cutting concrete foundation wall (most are).

Ceiling height

Denver requires a minimum 7’0” ceiling height in habitable rooms (with limited exceptions for beams). If your basement runs 6’10”, we can sometimes get it to code by lowering the floor, replacing soffited ducts with flat ones, or rerouting plumbing. Sometimes we can’t. We measure on day one and tell you straight.

Smoke and CO detection

Hard-wired smoke alarms (interconnected to upstairs system) and CO detectors are required in any sleeping area and at every level of the home. We bring everything up to current code as part of the work.

Bathroom ventilation

Required to terminate to the exterior — not the attic, not under the deck. Older basements sometimes have illegal venting we have to fix.

Structural changes (if you remove walls)

Any wall you suspect is load-bearing requires engineering. We pay for the structural engineer, draw the beams or posts, and submit them with the permit. Typical engineering cost: $800–$2,500 included in our scope.

Inspections you’ll see

A typical basement finish triggers these inspections in order:

1. Footing/foundation (only if pouring new concrete)
2. Underground plumbing (if adding a bathroom on slab)
3. Rough-in electrical
4. Rough-in plumbing
5. Rough-in mechanical (HVAC)
6. Framing
7. Insulation
8. Drywall
9. Final electrical
10. Final plumbing
11. Final mechanical
12. Final building

For an unbroken project, inspectors arrive within 24–48 hours of request. A typical basement schedule has 4–7 of these; the rest depend on scope. We coordinate every one — you don’t deal with the city.

Common mistakes that fail inspection

• Egress window well missing the ladder
• Smoke detectors on a separate circuit (must be interconnected)
• Bathroom fan venting into attic
• Plumbing without a vent
• GFCI/AFCI breakers missing on required circuits
• Stair handrail height (must be 34”–38”)
• Insufficient insulation R-value at rim joists

We’ve seen all of these, and they’re the reason DIY basements often stall. Get a contractor who knows the inspectors.

What we handle

For every basement we finish, our scope includes:

• All permit applications, drawings, and revisions
• Engineer coordination if structural
• All inspection scheduling
• Walking the inspector through (we’re on site for every inspection)
• Resolving any corrections same-day
• Final certificate of occupancy

You don’t see the permit office. That’s the whole point of hiring us.

If you’re considering a basement finish in Denver, start here or tell us about your project.