Residential Addition / Interior Remodel Permit in Twin Falls, Idaho

Twin Falls requires a residential addition / interior remodel permit for: Building permit required for additions and alterations to existing structures, including sunrooms and interior remodels affecting structural or life-safety elements; Use the Residential Addition Enclosed application for enclosed additions, the Residential Addition Not-Enclosed application for uncovered/open additions, or the Residential Interior Remodel application for interior work; Plans designed to the 2018 IRC and IECC with Idaho amendments and City of Twin Falls residential Design Criteria; Building permit valuation includes total project value (materials, labor, overhead and profit) for all work including any roofing, mechanical, electrical, and plumbing scope covered by the same permit; Engineering required for walls over 10 feet or non-prescriptive designs; Separate MEP permits required for any mechanical, electrical, or plumbing work. If your project isn't listed, confirm with City of Twin Falls Building Safety Department at (208) 735-7238 before starting work.

In Twin Falls, the published Building Permit Fee — valuation-based (same schedule as new construction) is: $22.00 minimum ($1-$500 valuation), scaling up per the Master City-Wide Fee Schedule building permit table (e.g., $63.00 for the first $2,000 plus $12.50 per additional $1,000 up to $25,000). Additional published fees: Residential Plan Review Fee — 30% of the building permit fee; Re-inspection Fee — $50.00. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Twin Falls's published plan-review target for a residential addition / interior remodel permit is 10–10 business days.

You'll need: Construction Drawings. Depending on your project, Twin Falls may also ask for: Residential Addition Enclosed Application; Residential Addition Not-Enclosed Application; Residential Interior Remodel Application. See the required-documents checklist on this page for details on each.

Twin Falls requires 3 inspection(s) for a residential addition / interior remodel permit, in order: Footing/Foundation, Rough-In, Final. Schedule each through City of Twin Falls Building Safety Department ((208) 735-7238).

Apply through City of Twin Falls Building Safety Department at 203 Main Avenue East, 2nd Floor of City Hall, Twin Falls, ID 83301 (P.O. Box 1907, Twin Falls, ID 83303-1907). Phone: (208) 735-7238, email: bsdpermits@tfid.org. Office hours: Building Safety Department, 2nd Floor of City Hall, 203 Main Avenue East, Twin Falls, ID 83301. Dedicated inspection request lines: Building Inspection (208) 735-7333, Plumbing Inspection (208) 735-7299, Mechanical Inspection (208) 735-7289, Electrical Inspection (208) 735-7235.. Official information: https://www.tfid.org/141/Building-Safety-Department.

Twin Falls, Idaho has adopted: Idaho Building Code Act (Idaho Code Title 39, Chapter 41) makes building code standards a matter of statewide concern; local governments that issue building permits and perform code enforcement must adopt the International Building Code and Idaho Residential Code (Parts I-III and IX) and the Idaho Energy Conservation Code as amended by the Idaho Building Code Board through negotiated rulemaking, and may not adopt subsequent IRC/IECC residential provisions not yet adopted by the Board. Source: Idaho Legislature, Idaho Code Title 39 Chapter 41 (39-4116, Local Government Adoption and Enforcement of Building Codes), https://legislature.idaho.gov/statutesrules/idstat/title39/t39ch41/; 2018 International Building Code (IBC), including accessibility appendices, adopted and incorporated by reference statewide with Idaho amendments; locally administered and enforced by the City of Twin Falls Building Safety Department for commercial construction within city limits. Source: City of Twin Falls Design Criteria: Commercial page and Idaho Building Code Act (Title 39 Ch. 41); 2018 International Residential Code (IRC), Parts I-VI and IX, Appendices A, B and G, with Idaho State amendments, adopted and locally administered by the City of Twin Falls for one- and two-family dwellings and townhouses within city limits. Source: City of Twin Falls Design Criteria: Residential page; 2018 International Energy Conservation Code (IECC), with Idaho State amendments, locally administered by the City of Twin Falls for residential construction. Source: City of Twin Falls Design Criteria: Residential page; 2023 National Electrical Code (NEC), per Idaho Rules and Amendments, locally administered and inspected by the City of Twin Falls Building Safety Department (dedicated Electrical Inspection line). Source: City of Twin Falls Design Criteria: Residential page and Inspections page; 2017 Idaho State Plumbing Code, locally administered and inspected by the City of Twin Falls Building Safety Department (dedicated Plumbing Inspection line). Source: City of Twin Falls Design Criteria: Residential page; City of Twin Falls has assumed local jurisdiction for issuing and inspecting building, electrical, plumbing, and mechanical permits within city limits (dedicated Building, Plumbing, Mechanical, and Electrical inspection phone lines are all City of Twin Falls Building Safety Department lines). The Idaho Division of Occupational and Professional Licenses (DOPL) separately registers/licenses electrical, plumbing, and HVAC contractors statewide (a distinct function from the City's permit issuance and inspection authority); DOPL's own Permits and Inspections program applies only in jurisdictions that have NOT assumed local authority, and DOPL confirms permit/inspection jurisdiction 'varies widely' by city/county assumption of authority. Source: DOPL Permits and Inspections page, https://dopl.idaho.gov/plb/plb-permits-and-inspections/, cross-checked against City of Twin Falls Inspections page listing City-run Building/Plumbing/Mechanical/Electrical inspection lines. Local amendments apply — see the Twin Falls overview page for the full list.

Use the Residential Addition Not-Enclosed application for an open/uncovered addition attached to the house, or the Residential Detached Accessory application if the deck is a separate, detached structure. Source: City of Twin Falls Building Applications & Forms page.