Room Addition Cost by State (2026)
The U.S. baseline for a room addition is $75/SF–$300/SF in 2026. The actual cost in your state depends on local construction labor rates. Pick a state below for a figure adjusted to that market (BLS QCEW), or see the national room addition cost guide.
| State | Typical / SF | vs. U.S. |
|---|---|---|
| California | $173/SF | +15.2% |
| Texas | $166/SF | +4% |
See all building types in The 2026 Construction Cost Index, or estimate your project with the free cost estimator.