Accessory Dwelling Unit / Single Apartment Building Permit in Silverthorne, Colorado

Silverthorne requires an accessory dwelling unit / single apartment building permit for: Attached Addition ADU: site plan with existing/proposed structures, construction management plan, erosion control/grading plan, overall floor plans (existing and proposed), stamped structurals by a licensed Colorado engineer, architectural elevations; Detached Structure ADU: site plan showing existing/proposed structures to-scale, overall floor plans, stamped structurals by a licensed Colorado engineer, architectural elevations; Remodel-of-Existing-Home ADU: site plan with ADU footprint outlined to scale, stamped overall floor plans showing existing/proposed scope of work, stamped structurals, architectural elevations if exterior is modified; HOA approval if applicable; warranty deed if applicable for new ownership; exterior lighting spec sheet (attached/detached types); outside agency approvals prior to issuance; Summit Fire & EMS fire mitigation permit for all new construction, additions, and decks; life-safety/sprinkler permit required for Eagles Nest Golf Course Filings 1-5 or homes over 6,000 SF; Plan Review: Town of Silverthorne Planning (and Engineering, for attached/detached types) Department(s) review per Town Code; Summit County Building Department conducts Building Code plan review. If your project isn't listed, confirm with Town of Silverthorne Community Development Department, Building Division at 970-262-7360 before starting work.

In Silverthorne, the published Plan Review Fee is: 65% of the Building Permit Fee. Additional published fees: Building Permit Fee (same valuation table as new construction) — $65.00 minimum, scaling per valuation tiers; Water and Sewer Tap Fees / Impact Fees / Stormwater System Development Fee — Applicable for attached-addition and detached-structure ADUs (new construction); the remodel-of-existing-home ADU type lists only permit fees and water/sewer tap fees due before issuance, no stormwater/impact fee listed. These are the jurisdiction's own published figures — see the fee schedule table and source citations on this page.

Silverthorne does not publish a plan-review timeline for this permit. Contact Town of Silverthorne Community Development Department, Building Division at 970-262-7360 for current turnaround.

You'll need: ADU Building Permit Application (SmartGov Portal); Stamped Structural Plans. See the required-documents checklist on this page for details on each.

Silverthorne requires 3 inspection(s) for an accessory dwelling unit / single apartment building permit, in order: Foundation (attached/detached new construction), Rough Frame / Rough Trades, Final Inspection. Schedule each through Town of Silverthorne Community Development Department, Building Division (970-262-7360).

Apply through Town of Silverthorne Community Development Department, Building Division at 601 Center Circle, P.O. Box 1309, Silverthorne, CO 80498. Phone: 970-262-7360, email: buildinginfo@silverthorne.org. Office hours: Monday through Friday, 8 a.m. to 5 p.m.; building permit submittal appointments required (per Community Development FAQ). Town Hall main line (970) 262-7300; Community Development/Building direct line (970) 262-7360. Electrical permits are handled separately by the Summit County Building Department, 0037 Peak One Drive / 37 S.C.R. 1005, Frisco, CO, (970) 668-3170.. Official information: https://www.silverthorne.org/town-government/community-development/building-copy.

Silverthorne, Colorado has adopted: 2018 International Building Code (IBC), with Town of Silverthorne local amendments — Town of Silverthorne Building Codes & Amendments page, https://www.silverthorne.org/town-government/community-development/building-copy/building-codes-construction-resources; 2018 International Fire Code (IFC), with Town of Silverthorne local amendments — same source; 2023 NFPA 70 National Electrical Code (NEC), adopted by Town Ordinance 2023-10 — the Town's own Building Codes & Amendments page attributes this specific adoption to the Summit County Building Department ('Ordinance 2023-10 2023 NFPA70 National Electrical Code Adoption - from the Summit County Building Department'), consistent with Summit County issuing and governing all electrical permits Town-wide; Underlying building-code plan review and inspection for all permit types is performed by the Summit County Building Department 'based on the Building Code most recently adopted by the Town' — Town of Silverthorne Plan Review page, https://www.silverthorne.org/town-government/community-development/building-copy/resubmittals-and-revisions; IRC Section 321.1 as locally amended (temporary/permanent address numbering requirements) and IBC Sections 105.4, 105.6, 109.1, 109.5, 109.7, 104.10, 104.11, and 3402.1 as locally amended (administrative provisions: permit suspension/revocation, inspection access, reinspection fees, code-modification authority, alternate materials/methods, and additions/alterations conforming to new-construction code) — Town of Silverthorne Building Codes & Construction Resources page, General Requirements / Administrative Requirements sections. Local amendments apply — see the Silverthorne overview page for the full list.

No. The Town publishes three separate ADU permit sub-types — attached addition, detached structure, and remodel of an existing home — each with its own application link, submittal checklist, and fee scope.