Planning project · Planning application
Block retaining wall proposed to replace railroad tie wall on hillside lot
The city treats the project as a Category II hillside review because of slope and unstable soils. A geotechnical report and engineering plans may be required. Staff would decide the application administratively.

From the filing
The application's description as it appears in City of Boise's record. See the official record
Cat II
Project name on file: 488 W SANDSTONE CT
Timeline
Oct. 13, 2026
10 documents added
Aug. 18, 2026
Concept Review Complete: Engineering Preview
Aug. 18, 2026
Concept Review Complete: Engineering Preview Complete
Based on submitted documents and limited overview of the property, a determination has been made that this project will be a Category II Hillside project due to slope, erosion-prone soils, unstable soils, earth movement, and other geologic and hydrologic hazards. In addition to the already submitted documents (please submit them with subsequent applications), additional documents may be required during the CFH Review process.Additional documents that you can expect to provide will be a site-specific geotechnical report with the possibility of a global slope stability analysis (please see the Agency Comment for Hillside Retaining Wall Permitting within this PLN); structural calculations for any retaining wall system that is greater than four feet in height from top of foundation to top of wall, that has more than one wall when the interior horizontal distance between the walls is less than 10 feet and the total height of all walls exceeds four feet, that has a surcharge, that has a backslope greater than three feet horizontal to one foot vertical, or that has structural components (these requirements will be assessed again at the time of occupancy); and civil plans. Please refer to the Hillside Development Requirements for Technical Reports for grading & drainage plan and geotechnical report requirements.A subgrade inspection by a geotechnical firm will be required at the time of construction once the subgrade is exposed and prior to placement of foundation materials or forms/rebar. A report of the inspection will need to be submitted to and accepted by PW Hillside (HillsideDrainage@cityofboise.org) before scheduling your inspection with the Building Department and receiving final occupancy.NOTE: The hazards of developing and building on a property, especially in the Boise foothills, are well known. It is the responsibility of the applicant/owner’s design, geological, and engineering professionals, not the City, to identify, address, and mitigate any hazards to the site. Satisfying these Conditions of Approval is for limited [City purpose] only and should not be relied on for design, geological or engineering purposes. Developer will comply with all requirements of Boise City Hillside Development Code Sections or submit evidence satisfactory to the Boise City Engineer that the proposed development is exempt from the requirements therein stated due to location, topography and/or the absence of adverse conditions associated with slope stability, ground water, erosion and sedimentation.If you would like to discuss this determination, please contact us at HillsideDrainage@cityofboise.org. Please include your application number and address in the subject line.
Aug. 18, 2026
Concept Review Complete: CR Complete - Type 2
Aug. 14, 2026
Concept Review Complete: Hillside Questionnaire Needed
Aug. 12, 2026
Application Submittal: Online
Aug. 12, 2026
Application filed
Documents
Plans
- Download Landscape plan with measurements and planting details
Residence landscaping plan showing plant materials legend, hardscape such as pavers, retaining walls, steps and a fire pit, with a scale and designer information.
Aug. 18, 2026 · 1 page · 18.4 MB · PDS-Other Small Docs
- Download Landscape plan with measurements and planting details
Residence landscaping plan showing plant materials legend, hardscape such as pavers, retaining walls, steps and a fire pit, with a scale and designer information.
Aug. 18, 2026 · 1 page · 18.4 MB · PDS-Other Small Docs
Project narrative
- Download Concept review summary report
Advisory concept review summary for a planned replacement of a railroad tie wall with a block wall, classifying the project as a Category II hillside project and listing expected technical documents.
Aug. 18, 2026 · 2 pages · 452 KB · PDS-Concept Review Summary Report
Application
- Download Planning project application form
Application to replace an existing railroad tie retaining wall with a block wall on an R-1A zoned residential lot, with applicant, owner and hillside questionnaire details.
Aug. 12, 2026 · 2 pages · 154 KB · PDS-Application
Photos
- Download Different angle of existing wall to be replaced
Photo showing an alternate view of the existing wall slated for replacement.
Aug. 12, 2026 · 1 page · 9.8 MB · PDS-Other Small Docs
- Download Wall replacement detail for existing angel
Aug. 12, 2026 · 1 page · 12.1 MB · PDS-Other Small Docs
- Download Railroad tie wall with fence on top
Single-page photo showing a railroad tie retaining wall with a fence on top, with a note that the future fence will sit behind the block wall.
Aug. 12, 2026 · 1 page · 9.6 MB · PDS-Other Small Docs
Correspondence
- Download Hillside retaining wall permitting guidance
Public Works guidance on when retaining walls in the hillside zone need a determination, slope stability analysis, and planning-code height and setback limits.
Aug. 18, 2026 · 5 pages · 804 KB · PDS-Agency Comments
Other documents
- Download Public Works hillside project questionnaire
Public Works questionnaire asking whether the project involves new parcels, additions, new dwellings, driveways, grading over 12 inches, or retaining walls.
Aug. 17, 2026 · 1 page · 154 KB · PDS-Other Small Docs
- Download Landscaping design showing walls and paver patio
Aug. 12, 2026 · 1 page · 3.2 MB · PDS-Other Small Docs

