Building Permit Costs for a Room Addition: What to Expect

Permit costs for a room addition vary widely—typically $500–$3,000+—depending on location, scope, and jurisdiction.

Key Cost Drivers

• Jurisdiction: City/county sets fees. High-cost areas (CA, NY, DC metro) charge more.
• Valuation-based fees: Many jurisdictions calculate fees as % of estimated construction cost (e.g., $5–$15 per $1,000 valuation).
• Size & complexity: Larger, structural additions (foundation, roof, load-bearing walls) cost more to permit.
• Trade permits: Separate electrical, plumbing, mechanical permits often required ($50–$300 each).
• Plan review: Fee for checking drawings against code.
• Impact fees: Some areas charge for schools, parks, traffic (can be thousands).

Typical Ranges

• Simple bump-out (no plumbing): $500–$1,500
• Bedroom/bath addition: $1,500–$4,000+
• Second-story / major structural: $3,000–$10,000+

Action Steps

1. Call your local building department – ask for fee schedule.
2. Provide rough plans for estimate.
3. Budget 1–3% of project cost for permits/fees.
4. Hire a contractor familiar with local process—they often handle permitting.

Unpermitted work risks fines, resale issues, insurance denial, and safety hazards. Permit first.