🏗️ Room Addition
Adding new conditioned square footage to the home — a bump-out or full expansion changing the footprint.
Permit requirements for Room Addition differ by state and city. The table below summarizes the rule in each covered state — open a state for full detail, fees, and official sources.
| State | Permit? | Authority | Typical fee | Timeline | Go / No-Go | Key notes |
|---|---|---|---|---|---|---|
| California | Permit required | city | Valuation-based building permit; impact fees may apply. Verify with the city building department. | 3–8 weeks. | Generally allowed | Expanding the footprint requires full plan review, zoning compliance with setbacks, and Title 24. Exempt: N/A |
| Texas | Permit required | city | Valuation-based building permit; impact fees may apply. Verify with the city building department. | 3–8 weeks. | Generally allowed | Expanding the footprint requires full plan review and zoning compliance. Exempt: N/A |
| Florida | Permit required | city | Valuation-based building permit; impact fees may apply. Verify with the city building department. | 3–8 weeks. | Generally allowed | Expanding the footprint requires FBC plan review and zoning compliance. Exempt: N/A |
| New York | Permit required | city | Valuation-based building permit; impact fees may apply. Verify with the city building department. | 3–8 weeks. | Generally allowed | Expanding the footprint requires full plan review; NYC uses New Building / ALT1 filings. Exempt: N/A |
| Pennsylvania | Permit required | city | Building permit fee based on valuation; zoning and plan review apply. | Plan-review permits typically ~15 business days in Philadelphia; larger additions longer. | Generally allowed | Room additions change the footprint and require a full building permit, zoning approval, and usually a site plan. |
| Illinois | Permit required | city | Building permit fee based on valuation; zoning and plan review apply. | — | Generally allowed | Room additions change the footprint and require a full building permit and zoning approval. Chicago uses the 2019 Chicago Building Code for plan review. |
| Ohio | Permit required | city | Building permit fee based on valuation; Columbus minimum $125 plus plan review. | Plan-review permits ~10+ business days (Columbus BZS). | Generally allowed | Room additions change the footprint and require a full building permit, zoning approval, and usually a site plan. |
| Georgia | Permit required | city | Building permit fee based on valuation; Atlanta minimum $150 plus $25 fee plus plan review. | — | Generally allowed | Room additions change the footprint and require a full building permit, zoning approval, and usually a site plan. |
| North Carolina | Permit required | city | Building permit based on valuation plus trade permits; verify with the city. | Plan review typically 3–6 weeks plus multiple inspections. | Generally allowed | Room additions change the footprint and require foundation, framing, egress, and trade reviews. Historic districts need a Certificate of Appropriateness. Exempt: Any new conditioned square footage requires a full permit. |
| Michigan | Permit required | city | Building permit based on valuation plus trade permits; verify with the city. | Plan review typically 3–6 weeks plus multiple inspections. | Generally allowed | Room additions change the footprint and require foundation, framing, egress, and trade reviews. Historic districts need a Certificate of Appropriateness. Exempt: Any new conditioned square footage requires a full permit. |
| New Jersey | Permit required | city | Construction permit based on valuation plus trade permits and zoning fee; verify with the city. | Plan review commonly 3–6 weeks plus multiple inspections; variances add time. | Generally allowed | Additions require zoning approval BEFORE the UCC building permit, structural drawings sealed by a NJ-licensed architect/engineer, and trade permits. Newark lots near max coverage may need a variance. Exempt: Any new conditioned square footage requires a full permit. |
| Virginia | Permit required | city | Building permit based on valuation plus trade permits and a 2% state levy; verify with the city. | Plan review ~10 business days (new construction) plus multiple inspections. | Generally allowed | Room additions change the footprint and require foundation, framing, egress, and trade reviews. Historic districts need design review. Exempt: Any new conditioned square footage requires a full permit. |
| Washington | Permit required | city | Valuation-based; includes trade permits. | Complex review 8–16 weeks. | Generally allowed | Middle-housing reforms (HB 1110) may allow more units by right; check zoning. Exempt: No exemption — any new conditioned footprint requires a permit. |
| Arizona | Permit required | city | Valuation-based; includes trade permits. | Phoenix 3–4 weeks plan review; 4–5 inspections. | Generally allowed | Lot-coverage and energy-code compliance are reviewed. Exempt: No exemption — any new conditioned footprint requires a permit. |
| Massachusetts | Permit required | city | Valuation-based; includes trade permits. | Worcester: 4–8 weeks; Boston zoning review may add time. | Generally allowed | Boston additions may require a Zoning Board of Appeal hearing if beyond the envelope. Exempt: No exemption — any new conditioned footprint requires a permit. |
| Tennessee | Permit required | city | Valuation-based; includes trade permits. | Nashville standard residential review targets ~5 business days. | Generally allowed | The addition must meet code even though the existing home is not brought up to code. Exempt: State program: additions over 30 sq ft require a permit. |
| Indiana | Permit required | city | Building permit fee based on valuation; zoning and plan review apply. | Plan-review permits take longer; timelines vary by city. | Generally allowed | Room additions change the footprint and require a full building permit, zoning approval, and usually a site plan. |
| Missouri | Permit required | city | Building permit fee based on valuation; zoning and plan review apply. | Varies by municipality — typically several weeks for full plan review. | Generally allowed | Room additions change the footprint and require a full building permit, zoning approval and usually a site plan. |
| Maryland | Permit required | city | Building permit fee based on valuation; zoning and plan review apply. | — | Generally allowed | Room additions require a full building permit, zoning approval, and usually a site plan. |
| Wisconsin | Permit required | city | Building permit fee based on valuation; zoning and plan review apply. | Varies by municipality — typically several weeks for full plan review. | Generally allowed | Room additions change the footprint and require a full UDC building permit, zoning approval and usually a site plan. |