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Foothills/hillside · Planning application

Oversized detached garage built into hillside approved with conditions

The city's planning director approved a detached garage of over 1,000 square feet or over 22 feet tall in front of an existing home on 1.56 acres. Conditions limit retaining wall heights, bar commercial use and require a paved driveway with a landscape buffer.

ApprovedCFH25-00087Filed March 3, 2026Highlands · 4425 N Cartwright Rd+1 related filing
Site plan for Oversized detached garage built into hillside approved with conditions
Site plan from the application documents.
Pin at the reported location; the shaded outline is the primary parcel (Ada County).

From the filing

The application's description as it appears in City of Boise's record. See the official record

The owner of an existing single-family home at 4425 N Cartwright Rd in Boise's Grassy subdivision wants to build a detached garage in front of the house. The city's planning director approved it because the steep, limited buildable lot makes it hard to place the garage elsewhere. The garage is proposed to be over 1,000 square feet and/or over 22 feet tall, and its side and back walls would be retaining walls holding back the hillside.

Detached garage in Hillside overlay.

Project name on file: 4425 N CARTWRIGHT RD

Timeline

  1. Oct. 6, 2026

    Review Complete: Completed

  2. Oct. 6, 2026

    Current Planning: Complete

  3. Sept. 4, 2026

    Current Planning: In Review

  4. Sept. 4, 2026

    Assign Reviewers: Completed

  5. Aug. 18, 2026

    Review Complete: Corrections Required

  6. Aug. 18, 2026

    Current Planning: Corrections Required

  7. July 22, 2026

    Current Planning: In Review

  8. July 22, 2026

    Assign Reviewers: Completed

  9. July 15, 2026

    Fee Payment: Payment Received

  10. July 15, 2026

    Prescreen Review: Passed

  11. July 14, 2026

    Prescreen Review: In Progress

  12. July 9, 2026

    Prescreen Review: Corrections Required

  13. July 8, 2026

    Prescreen Review: In Progress

  14. March 3, 2026

    Application Submittal: ePlanReview

  15. March 3, 2026

    Application filed

Documents

Site plans

  • Revised site plan sheet with sheet notes, code compliance data (A-1 zone, setbacks, 45-ft maximum height), material legend, and keynotes for retaining walls and a proposed garage.

    Oct. 6, 2026 · 2 pages · 814 KB · PDS-Maps and Drawings

    Download Revised site plan
  • Planning concept review summary for a Category II hillside project covering an accessory garage, with notes on required application, driveway limits, and expected geotechnical and structural documents.

    July 30, 2026 · 2 pages · 456 KB · PDS-Concept Review Summary Report

    Download Concept review summary report
  • Dated July 15, 2026 site plan showing sheet notes, A-1 zone code compliance data (setbacks and 45-foot maximum height), a material legend, and keynotes for retaining wall and garage work.

    July 30, 2026 · 2 pages · 710 KB · PDS-Maps and Drawings

    Download Site plan with sheet notes, setbacks and keynotes

Plans

  • Revised erosion and sediment control (ESC) plan sheet with general notes on BMP inspections, dewatering, stockpiles, sawcutting slurry, and excess material disposal.

    Oct. 6, 2026 · 2 pages · 761 KB · PDS-Maps and Drawings

    Download Revised erosion and sediment control plan
  • Revised grading plan for a hillside application showing existing and proposed contours at 1-foot intervals, spot elevations, and general sheet notes on contractor coordination and underground utilities.

    Oct. 6, 2026 · 3 pages · 1.4 MB · PDS-Maps and Drawings

    Download Revised grading plan, sheet C3.00
  • Structural cover sheet for a detached garage project, with abbreviations, design codes, general notes and the sheet list for the structural drawing set.

    Oct. 6, 2026 · 9 pages · 1.7 MB · PDS-Maps and Drawings

    Download Structural drawings, cover sheet and sheet list
  • Architectural elevation drawings for a residential garage addition, with general construction notes, materials, and building heights, marked issued for permit.

    July 30, 2026 · 2 pages · 1.3 MB · PDS-Maps and Drawings

    Download Garage building elevations, east and west
  • General notes and contact information for the erosion and sediment control plan, covering BMP inspections, dewatering, portable restrooms, sawcutting slurry and excess material disposal.

    July 30, 2026 · 2 pages · 727 KB · PDS-Maps and Drawings

    Download Erosion and sediment control plan
  • Grading plan sheet C4.00 with existing and proposed contours at 1-foot intervals, spot elevations, keynotes and a note on finish floor elevation reference, marked not for construction.

    July 30, 2026 · 1 page · 886 KB · PDS-Maps and Drawings

    Download Grading plan

Project narrative

  • Applicant's letter describing a detached garage addition built into the hillside, matching the existing residence's architecture and materials, with no new driveway or living area.

    July 30, 2026 · 3 pages · 16.8 MB · PDS-Letter of Intent

    Download Detailed letter of explanation for detached garage addition

Decisions

  • Planning Director's October 6, 2026 letter approving a waiver to place a detached garage in front of an existing home on a constrained hillside lot, with conditions.

    Oct. 6, 2026 · 7 pages · 221 KB · PDS-Action Letter

    Download Administrative approval letter for hillside garage

Notices

  • Notice that a hillside approval was granted for a detached garage in front of an existing home, with an appeal deadline of October 16, 2026.

    Oct. 2, 2026 · 2 pages · 765 KB · PDS-Legal Notice

    Download Notice of approval for detached garage

Application

  • Application for a detached garage on a single-lot residential parcel in the Hillside overlay, filed under Category II with the applicant as property owner.

    July 30, 2026 · 2 pages · 196 KB · PDS-Application

    Download Hillside and foothills development application
  • Application for a detached garage in a Hillside overlay on a 1.56-acre A-1 zoned lot, filed as Category II with a Fire Prevention section and submittal requirements.

    July 15, 2026 · 2 pages · 199 KB · PDS-Application

    Download Hillside and foothills development application
  • Application for a detached garage in a Hillside overlay on a 1.56-acre A-1 zoned lot, filed as Category II with a Fire Prevention section and submittal requirements.

    March 3, 2026 · 2 pages · 203 KB · PDS-Application

    Download Hillside and foothills development application

Studies and reports

  • Atlas update to the original geotechnical report for a detached garage, covering a retaining wall up to about 6 feet and revisions to 2003 IBC references to the 2018 IBC.

    Oct. 6, 2026 · 2 pages · 402 KB · PDS-Other Small Docs

    Download Geotechnical report update letter, revision 1
  • Engineer's response letter dated Aug. 31, 2026, answering plan review comments on the retaining wall, shear walls, legend and impervious surface, with some items deferred to the architect.

    Oct. 6, 2026 · 1 page · 309 KB · PDS-Other Small Docs

    Download Structural response letter to plan review comments
  • Update letter revising a 2006 geotechnical report for a detached garage, changing code references from the 2003 to the 2018 International Building Code.

    July 30, 2026 · 2 pages · 285 KB · PDS-Other Small Docs

    Download Geotechnical report update letter
  • A 2006 geotechnical and foundation evaluation by Materials Testing & Inspection for a proposed residence on the lot, with groundwater and construction recommendations.

    July 30, 2026 · 29 pages · 8.7 MB · PDS-Other Small Docs

    Download Original geotechnical engineering report

Photos

Correspondence

  • Fire department approval subject to conditions, including wildland-urban interface defensible space, a 5-foot fuel-free area, a 30-foot setback from open space, and no open flames.

    Oct. 6, 2026 · 3 pages · 496 KB · PDS-Agency Comments

    Download Boise Fire Department comments
  • Parks and Community Forestry reviewed the plans and have no comments, noting about three trees would be removed for a garage but no mitigation is required.

    Oct. 6, 2026 · 1 page · 58 KB · PDS-Agency Comments

    Download Boise Parks and Recreation comments
  • Public Works finds the garage project suitable for the site if listed conditions are met, including retaining wall design and geotechnical recommendations.

    Oct. 6, 2026 · 3 pages · 173 KB · PDS-Agency Comments

    Download Public Works drainage and hillside comments
  • Public Works says sewer connection is required for plumbing fixtures, sewer is available onsite, and sewer capacity fees may apply at building permit issuance.

    Oct. 6, 2026 · 1 page · 65 KB · PDS-Agency Comments

    Download Public Works sewer comments
  • Applicant's written responses to Public Works Hillside review comments on retaining wall structural calculations, legend, drainage and swale condition, dated Aug. 18, 2026.

    Oct. 6, 2026 · 1 page · 51 KB · PDS-Other Small Docs

    Download Public Works comments response, cycle 1
  • Veolia Water Idaho reports available water pressure and flow at a nearby hydrant for fire sprinkler design, to be attached to architectural plan sets.

    July 30, 2026 · 1 page · 111 KB · PDS-Other Small Docs

    Download Veolia Water fire flow availability letter

Other documents

  • Noticing radius map

    Map showing the area within the notice radius for neighboring property owners who were sent notice of the application.

    Oct. 2, 2026 · 527 KB · PDS-Maps and Drawings

  • Checklist answers on a hillside project: grading over 12 inches deep and a retaining wall are indicated, with no new parcels, dwellings, driveways or additions; wall height and spacing questions are answered no.

    July 30, 2026 · 1 page · 103 KB · PDS-Other Small Docs

    Download Public Works hillside project questionnaire
  • Statement of legal interest

    July 30, 2026 · 101 KB · PDS-Statement of Legal Interest

  • Transmittal to review agencies

    July 30, 2026 · 133 KB · PDS-Transmittal Agencies

  • Fee receipt

    July 15, 2026 · 131 KB · PDS-Receipts

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