Remodel - Basement Cost in O Fallon, MO in 2026
Most Remodel - Basement projects in O Fallon, MO cost between $59,000 and $275,000. The typical price is $125,000.
Basements are cheaper per square foot because the shell already exists.
O Fallon prices track the national average closely. Costs here are close enough to the national picture that the adjustment barely moves the number.
What drives the price
- Whether the addition needs its own foundation and roof tie-in
- Adding a bathroom or kitchen (plumbing and electrical runs)
- Structural work to the existing wall being opened up
- Local permit and inspection requirements
Usually included
- Framing, roofing and siding to match
- Electrical rough-in and finish
- Insulation, drywall and paint
- Flooring and trim
Usually extra
- Permits and architectural drawings
- Site work or tree removal
- High-end fixtures and appliances
Unit prices in O Fallon, MO
| Quality tier | Cost per sq ft |
|---|---|
| Budget | $84 |
| Mid-range | $180 |
| High-end | $390 |