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Commercial Tenant Improvement / Addition-Alteration Permit in Lewiston, Idaho

Required for remodels, alterations, and tenant improvement (TI) work in existing commercial space in the City of Lewiston. TI work is issued as a Building Permit (plus any needed trade permits) under the same 2018 IBC (as locally adopted, including 2021 Mass Timber provisions) and 2018 IEBC (International Existing Building Code) used for new commercial construction, billed on the same valuation-based Commercial Building Permit Fee table. The City's Permit Review Schedule separately tracks 'Major Addition or Alteration/Tenant Improvement' and 'Minor Addition or Alteration/Tenant Improvement' for review-turnaround purposes; as of this verification both currently carry the same published maximum (14 calendar days, 8 for minor revisions).

Verified 2026-08-02 · Source

When you need this permit

  • Building permit required whenever a building or structure regulated by the code is altered, converted, enlarged, improved, or repaired -- City of Lewiston Permits Needed page (covers TI/remodel work in existing commercial space)
  • Plans reviewed against the 2018 IBC (+ 2021 IBC Mass Timber provisions, adopted January 2025) and the 2018 International Existing Building Code (IEBC, adopted January 2021), plus the applicable trade codes (2018 IMC, 2017 Idaho State Plumbing Code, 2023 NEC, 2018 IECC) as locally adopted
  • A completed Code Analysis for Commercial/Multi-Family Projects form IS REQUIRED on all commercial plan submittals, including TI/remodel projects, prepared by an Idaho-licensed Design Professional per IBC Section 107 and Idaho Code Title 54
  • Building valuation for the TI scope of work calculated per IBC Section 109.3 as adopted and amended by the City, using the same Commercial Building Permit Fee valuation table applied to new commercial construction -- there is no separate, discounted 'TI fee schedule'
  • Separate electrical, mechanical, and plumbing permits required for trade work within the TI scope, billed under the Commercial, Multi-family (3+ units), Industrial, and Alternative Energy valuation-based fee tables
  • The City's Permit Review Schedule page publishes separate 'Major Addition or Alteration/Tenant Improvement' and 'Minor Addition or Alteration/Tenant Improvement' rows (each including electrical, mechanical, plumbing, utility, and any others associated) -- both currently list a maximum of 14 calendar days, 8 calendar days for minor revisions; the page does not define a numeric threshold distinguishing 'major' from 'minor,' so applicants should confirm the classification with Building Services

Required documents

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Fee schedule

Commercial Building Permit Fee -- valuation up to $500 (same table used for new commercial construction)City of Lewiston FY2026 Fee Schedule (Resolution 2025-39, effective 10/1/2025), Schedule F, Commercial Building Permit Fees -- TI/remodel work is billed on the same valuation-based Commercial Building Permit Fee table as new commercial construction; see the commercial-building-permit entry in this file for the full valuation tier table.
$40.10
Commercial Building Permit Fee -- valuation $2,001 to $25,000City of Lewiston FY2026 Fee Schedule, Schedule F, Commercial Building Permit Fees -- a representative mid-range tier for a typical TI project; see the commercial-building-permit entry for all 8 valuation tiers.
$134.89 for the first $2,000 plus $24.19 for each additional $1,000 or fraction thereof
Commercial Building Permit Fee -- valuation $25,001 to $50,000City of Lewiston FY2026 Fee Schedule, Schedule F, Commercial Building Permit Fees.
$684.33 for the first $25,000 plus $17.30 for each additional $1,000 or fraction thereof
Building Permit Plan Review FeeCity of Lewiston FY2026 Fee Schedule, Schedule F, Building Plan Review Fees.
65% of the Building Permit Fee
Additional Plan Review (changes, additions, or revisions to plans)City of Lewiston FY2026 Fee Schedule, Schedule F, Building Plan Review Fees.
$72.20 per hour, minimum 2 hours
Electrical/Mechanical/Plumbing Trade Permits (if applicable)City of Lewiston FY2026 Fee Schedule, Schedule F -- each trade permit is separately issued and fee-assessed from the Building Permit.
Billed on the same Commercial, Multi-family (3+ units), Industrial, and Alternative Energy valuation-based tiers used by the standalone electrical-permit, plumbing-permit, and mechanical-hvac-permit entries in this file
Fire Sprinklers -- Repair or Modification (if the TI scope modifies an existing system)City of Lewiston FY2026 Fee Schedule, Schedule F, Fire Fee Schedule -- applies to Residential, Commercial, and Industrial alike; relevant when TI work modifies existing fire sprinkler coverage.
$111.05 plus $2.22 per head
Fire Alarm -- Repair or Modification (if the TI scope modifies an existing system)City of Lewiston FY2026 Fee Schedule, Schedule F, Fire Fee Schedule.
$111.05 plus $2.22 per device
Conditional Certificate of OccupancyCity of Lewiston FY2026 Fee Schedule, Schedule F, Other Permit Fees -- applies if occupancy is requested before the project is fully complete.
$346.87

Review timeline

Plan reviewLewiston’s published plan-review target
8–14 business days

How long did your Commercial Tenant Improvement / Addition-Alteration Permit permit actually take in Lewiston?

Anonymous — one question, no email. Answers are combined and only shown once at least 5 people have reported.

Inspection process

  1. 1

    Rough-In (Electrical, Mechanical, Plumbing)

    Trade rough-in inspections for the separately permitted electrical, mechanical, and plumbing scopes within the TI area, as applicable to the project.

  2. 2

    Fire Sprinkler/Alarm (if modified)

    Inspected under the separate Fire Fee Schedule if the TI scope modifies existing fire sprinkler or fire alarm coverage.

  3. 3

    Accessibility

    Verification of the accessible route, restrooms, and other applicable elements against IBC Chapter 11 / ICC A117.1-2009 scoping and technical requirements for the altered space.

  4. 4

    Final / Certificate of Occupancy

    Final building and trade inspections prior to occupancy of the improved space; a Conditional Certificate of Occupancy ($346.87) may be requested if occupancy is needed before full completion.

See the full Lewiston inspection guide — scheduling & re-inspection fees →

Tips

  • Lewiston does not have a separate, discounted 'TI fee schedule' -- a tenant improvement project is billed on the same valuation-based Commercial Building Permit Fee table as new commercial construction, using the value of the TI scope of work.
  • The Permit Review Schedule page tracks 'Major' and 'Minor' Addition/Alteration/TI as two separate rows, but both currently publish the identical 14-day maximum (8 for minor revisions) -- the major/minor distinction does not currently change the published turnaround time, though it may affect required documentation or review complexity; ask Building Services which classification applies to your project.
  • If your TI scope changes occupancy classification, egress, or accessible elements, budget for the corresponding Accessibility Review and Energy Review document sets described in the City's Plan Review Documents Checklist, in addition to the base Complete Review package.
  • A remodel that touches an existing fire sprinkler or fire alarm system triggers the separate Fire Fee Schedule (Repair or Modification tiers), on top of the Building Permit fee -- confirm with Building Services whether your TI scope requires fire system permits.
  • Reactivation of an expired TI permit costs 25% of the original application fee if there has been no building or trade code change since the original review, or 50% if there has been a code change -- City of Lewiston FY2026 Fee Schedule, Schedule F.

Frequently asked questions

Lewiston requires a commercial tenant improvement / addition-alteration permit for: Building permit required whenever a building or structure regulated by the code is altered, converted, enlarged, improved, or repaired -- City of Lewiston Permits Needed page (covers TI/remodel work in existing commercial space); Plans reviewed against the 2018 IBC (+ 2021 IBC Mass Timber provisions, adopted January 2025) and the 2018 International Existing Building Code (IEBC, adopted January 2021), plus the applicable trade codes (2018 IMC, 2017 Idaho State Plumbing Code, 2023 NEC, 2018 IECC) as locally adopted; A completed Code Analysis for Commercial/Multi-Family Projects form IS REQUIRED on all commercial plan submittals, including TI/remodel projects, prepared by an Idaho-licensed Design Professional per IBC Section 107 and Idaho Code Title 54; Building valuation for the TI scope of work calculated per IBC Section 109.3 as adopted and amended by the City, using the same Commercial Building Permit Fee valuation table applied to new commercial construction -- there is no separate, discounted 'TI fee schedule'; Separate electrical, mechanical, and plumbing permits required for trade work within the TI scope, billed under the Commercial, Multi-family (3+ units), Industrial, and Alternative Energy valuation-based fee tables; The City's Permit Review Schedule page publishes separate 'Major Addition or Alteration/Tenant Improvement' and 'Minor Addition or Alteration/Tenant Improvement' rows (each including electrical, mechanical, plumbing, utility, and any others associated) -- both currently list a maximum of 14 calendar days, 8 calendar days for minor revisions; the page does not define a numeric threshold distinguishing 'major' from 'minor,' so applicants should confirm the classification with Building Services. If your project isn't listed, confirm with City of Lewiston Building Services (Community Development Department) at (208) 746-1318, option 1 for Permit Representatives before starting work.

The fee is valuation-based on the value of the tenant improvement scope of work, using the same Commercial Building Permit Fee table (FY2026 Fee Schedule, Resolution 2025-39) applied to new commercial construction, plus a Building Permit Plan Review Fee of 65% of that fee and any applicable trade (electrical/mechanical/plumbing) or fire permit fees.

Per the City's live Permit Review Schedule page, both 'Major' and 'Minor Addition or Alteration/Tenant Improvement' have a maximum turnaround of 14 calendar days, 8 calendar days for minor revisions. This is shorter than the 21-day maximum published for entirely new commercial construction.

You'll need: Building Permit Application; Code Analysis for Commercial/Multi-Family Projects; Plan Review Documents Checklist. See the required-documents checklist on this page for details on each.

Lewiston requires 4 inspection(s) for a commercial tenant improvement / addition-alteration permit, in order: Rough-In (Electrical, Mechanical, Plumbing), Fire Sprinkler/Alarm (if modified), Accessibility, Final / Certificate of Occupancy. Schedule each through City of Lewiston Building Services (Community Development Department) ((208) 746-1318, option 1 for Permit Representatives).

Apply through City of Lewiston Building Services (Community Development Department) at 215 D Street, Lewiston, ID 83501 (P.O. Box 617, Lewiston, ID 83501). Phone: (208) 746-1318, option 1 for Permit Representatives, email: cd@cityoflewiston.org. Office hours: Monday-Friday, 8:00 AM to 5:00 PM. Building Official: Jeff Wolfe, (509) 254-3275, jwolfe@cityoflewiston.org. Permit Representatives: Lorrie Tanguay, (208) 746-1318 ext. 7203; Adrian Miller, (208) 746-1318 ext. 7263.. Official information: https://www.cityoflewiston.org/227/Building-Services.

Lewiston, Idaho has adopted: 2018 International Building Code (IBC), plus 2021 IBC Mass Timber provisions, adopted January 2025 for commercial construction — City of Lewiston Current Codes page (Lewiston City Code Sec. 10-1, Code Adoption).; 2018 International Residential Code (IRC), adopted January 2021, for one- and two-family dwellings and townhouses — City of Lewiston Current Codes page.; 2018 International Energy Conservation Code (IECC), adopted January 2021 — City of Lewiston Current Codes page.; 2018 International Mechanical Code (IMC), adopted January 2021 — City of Lewiston Current Codes page.; Idaho State Plumbing Code, based on the 2015 Uniform Plumbing Code (UPC), adopted January 2021 — City of Lewiston Current Codes page.; 2018 International Fire Code (IFC), adopted January 2021 — City of Lewiston Current Codes page.; 2023 National Electrical Code (NEC), adopted January 2025 — City of Lewiston Current Codes page.; 2018 International Existing Building Code (IEBC), adopted January 2021 — City of Lewiston Current Codes page.; The Current Codes page states local amendments to the adopted codes exist and directs readers to Lewiston City Code Sec. 10-1 (Code Adoption) for the specific amendment text; the amendments themselves are not individually enumerated on the Current Codes web page.. Local amendments apply — see the Lewiston overview page for the full list.

There is no separate TI permit product. A tenant improvement or commercial remodel is issued as a Building Permit (plus any needed trade permits), billed on the same valuation-based Commercial Building Permit Fee table as new commercial construction. The City's Permit Review Schedule page does separately track 'Major' and 'Minor' Addition or Alteration/Tenant Improvement for review-turnaround purposes, but both currently share the same published 14-day maximum (8 for minor revisions).

Sources & verification

Verified against official sources. Last reviewed 2026-08-02.

Fees, timelines, and adopted codes are researched from each jurisdiction's published records — see how we verify. Requirements change and vary by project, so always confirm the current details with the Lewiston building department before you submit. PermitBase is an independent reference and is not affiliated with any government agency.

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