Basement finishing cost in Marietta: the ranges, reconciled
| Source | Range | Notes |
|---|---|---|
| Angi, Atlanta | $30–$80/sq ft | 1,000 sq ft = $30,000–$80,000 |
| Heide Contracting guide, Smyrna/Cobb | $45–$95/sq ft | Value tier 700–900 sq ft: $35,000–$60,000; mid 800–1,200 sq ft: $60,000–$110,000 |
| Silver Oak, Atlanta design-build | $85,000+ starter | Design/permits/management included |
Market guide ranges, October 2026 — published Atlanta/Marietta sources and Remodeling Magazine Cost vs. Value 2025 (Atlanta), reconciled in our research. These are planning ranges, not a quote for your home; your written scope sets your price.
A bathroom is the biggest lever (below-grade plumbing can need an ejector pump), followed by egress windows for bedrooms and the moisture scope.
Finish in the wrong order and redo it
Georgia basement guidance is consistent: drainage and water management first, vapour control second, finishes last. Red clay, sloped lots and humidity punish the reverse order. Our basement finishing page gives the full sequence, including smoke/CO and egress rules for terrace-level bedrooms under Georgia's 2024-adopted residential code.
A worked example: the same 900 square feet, three honest totals
Take a 900-square-foot terrace level and run the published ranges already reconciled above. At Angi's Atlanta band of $30–$80 per square foot, the arithmetic gives $27,000 to $72,000. At the Smyrna and Cobb guide's $45–$95 per square foot, the same room gives $40,500 to $85,500. A design-build scope including design, permits and management starts higher still — the Atlanta design-build source in our research puts starter basements at $85,000+. None of these totals is the price of your basement; together they show what each kind of quote includes, and why the lowest number in a search result and the highest number in a showroom can both be describing real work at different scopes.
What the bedroom decision adds
Calling one of those finished rooms a bedroom triggers requirements a media room escapes: an emergency escape and rescue opening meeting Georgia's 2024-adopted residential code, plus smoke alarms in the room, outside the sleeping area and on the level, with carbon-monoxide alarms where the home has fuel-burning appliances or an attached garage. Permitted alterations and newly created sleeping rooms are exactly what brings those alarm rules into an existing home, so decide the room's legal use before framing — retrofitting egress after the walls are up is the expensive way to change your mind.