Quick answer: Finishing a basement in the Denver metro runs about $45 to $100 per square foot, with an average project near $33,900 and most falling between about $15,900 and $79,400, according to Angi’s Denver cost data. In Longmont, finishing a basement typically runs $25 to $60 per square foot, or about $25,000 to $60,000 for a 1,000 sq ft basement. The biggest swings come from adding a bathroom, cutting in egress windows, ceiling height and ductwork, and moisture or radon fixes.
Colorado Basement Finishing Cost at a Glance
| Cost item | Typical range |
|---|---|
| Basement finish, per square foot (Denver metro) | $45–$100 |
| Average full project (Denver metro) | About $33,900 |
| Finish in Longmont ($25–$60/sq ft) | $25,000–$60,000 |
| Egress window, each | $4,000–$7,500 |
| Permit fees | $600–$2,500, or a percentage of project value |
| Waterproofing | About $3–$10 per sq ft |
| Sump pump | $450–$2,600 |
Denver-metro figures are from Angi’s Denver cost data; the Longmont range is from our own basement finishing projects. Your actual number depends on your basement, so a site visit is the only way to get a firm price.
What Drives the Cost of a Basement Finish
1. Square footage and layout
More finished area means more framing, drywall, flooring and paint. Open rec rooms cost less per square foot than layouts with several bedrooms and closets.
2. Bedrooms and egress windows
Any basement bedroom needs an emergency escape opening under the residential code, usually an egress window with a window well. Cutting the foundation and installing the well is one of the biggest single line items. See our egress window installation page and our egress window contractor guide.
3. Bathroom
A basement bathroom is much cheaper if the builder left plumbing rough-ins. Without them, the slab has to be cut and the drain tied in, and sometimes an ejector pump is needed.
4. Ceiling height, ducts and beams
Low ductwork, beams and plumbing runs have to be boxed in or rerouted, and bedrooms and living areas need minimum ceiling heights. More soffits mean more labor.
5. Moisture and radon
Colorado’s health department classifies all 64 Colorado counties as radon Zone 1, meaning high risk. Test before you finish and add mitigation if levels are high. Fix any water intrusion before framing, because finishing over a damp wall traps moisture and leads to mold.
6. Finish level
Carpet versus luxury vinyl plank, a wet bar, a home theater or built-ins can move the total by tens of thousands of dollars.
Do You Need a Permit to Finish a Basement in Colorado?
In most Front Range cities, yes. Longmont and Greeley both list basement finishes as permit work. A permit means framing, electrical, plumbing, mechanical and insulation inspections, which protect you at resale. Unpermitted basements often have to be opened up when a buyer’s inspector finds them. More on local rules: finishing a basement in Boulder and basement finishing in Denver.
Typical Basement Finish Timeline
- Design, estimate and permit application.
- Radon test and any moisture fixes.
- Framing, then rough electrical, plumbing and HVAC.
- Rough inspections, then insulation and its inspection.
- Drywall, paint and trim.
- Flooring, doors, fixtures and final inspection.
If you are searching for basement costs in Colorado Springs or Pueblo, the same cost drivers apply. We work the Front Range from Longmont and Boulder County down through the Denver metro.
Basement Finishing Cost FAQs
How much does it cost to finish a basement in Colorado?
In the Denver metro, finishing a basement runs about $45 to $100 per square foot, and the average project is near $33,900 according to Angi. In Longmont, finishing a basement typically runs $25 to $60 per square foot, or about $25,000 to $60,000 for 1,000 sq ft.
How much does an egress window add to a basement finish?
An egress window with a window well typically costs $4,000 to $7,500 each in the Denver metro. Any basement bedroom needs one.
Do I need a permit to finish my basement?
In most Front Range cities, yes. Longmont and Greeley both list basement finishes as permit work, with framing, electrical, plumbing and insulation inspections.
Should I test for radon before finishing a basement in Colorado?
Yes. All 64 Colorado counties are classified as radon Zone 1, high risk. Test first and install mitigation if levels are above the EPA action level.
What is the cheapest way to finish a basement?
Keep an open layout, use existing plumbing rough-ins and window openings, and choose durable mid-range flooring. Bedrooms and new bathrooms add the most cost.
Get a Basement Finishing Estimate
We visit, measure, check moisture and egress, and give you a written, itemized price. We pull the permit and handle every inspection. Josh Brooks Construction and Renovation Inc. is a licensed general contractor based in Longmont with 30 years in construction, serving 46+ Front Range cities. Call 720-828-7997 or text 720-453-5095 for a free estimate.
Licensed. Local. Not a storm chaser.
Sources
- Angi: How Much Does It Cost to Finish a Basement in Denver, CO?
- Colorado Department of Public Health and Environment: all 64 Colorado counties are radon Zone 1 (high risk)
- City of Longmont Building Services: Permits (siding, window replacement and basement finish listed as permit work)
- City of Greeley: Building Permits and Inspections
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