Accessory structures are detached buildings or structures such as private garages, sheds, carports, decks, patio covers, pools and similar structures. Such structures are constructed to serve an existing residence and may not be used for human occupancy.

A building permit is required for accessory structures, except for one story detached accessory structures used as sheds, playhouses and similar small buildings that are 200 square feet or less in floor area. A building permit is required for any plumbing, electrical or gas line installation.

When a building permit is required for an accessory structure, see inspections required as applicable.

Please call 801-208-3127 to schedule an inspection. Please call before 1 p.m. the day before you need an inspection, and have your permit number available.

Accessory structures are permitted uses in the residential zoning districts. Site and building plan review and approval by the Planning Commission and City Council may be required with regard to other zoning districts. Pole sheds and pole barns are not permitted as accessory structures. Accessory structures must not be constructed over property easements. Accessory structures on residential properties must be setback from property lines at least 5 feet, check with Planning dept. for any lot easements.

See Title 18 for each Zone.

On any lot, the combined floor area of the detached accessory building(s) and the primary Structure shall not exceed 30% of the entire lot area. Additionally the detached accessory building may not exceed 25% of the rear yard area.

Detached accessory structures must not exceed 20 feet in height, except on lots of at least one (1) acre, where structures may not exceed 25 feet in height. Height is measured from finish grade to peak.

Exterior materials shall be in compliance with Riverton City Land Use Code

Submittals Required for Permit
Two (2) copies of construction plans showing proposed designs and materials. Drawings are to be drawn to at least 1/4” scale on paper and may include.

  1. Site Plan – showing lot dimensions and locations of existing and proposed structure(s).
  2. Floor Plan – Outside lines and dimensions of the structures, location of interior walls, size and spacing of footings, slabs, joist, rafters, headers, etc.
  3. Cross Sections and/or Elevations – rear or side views showing:
    • Depth and type of footing and foundation
    • Material specifications for walls, roof and floors
    • Manner of construction

Plan Examples and Notes

Structural Recommendations
Foundations: The foundation for detached garage or shed up to 600 sq. feet, having a maximum wall height of 10 feet and a maximum width/length shall be no more than 30 feet may use the Riverton City approved monolithic drawing. All structures over 600 sq. feet or have wall heights exceeding 10 feet are required to use standard footing and foundation for support.
Framing: The following conventional framing methods are recommended for the construction of garages and shed.


  1. Bottom plate to be one treated or foundation grade redwood 2” x 4” anchored by approved strap anchors of ½” x 10” bolts, with 3” x 3” plate washer and nut spaced not more than one foot from each corner or end of plate and 32” on center.
  2. Studs (2” x 4”) spaced 16” on center, with three studs at exterior corners.
  3. Top plate two (2” x 4”) lapped at corners and overlapped at least 24” at splices.
  4. Wall sheathing panel sheathing (plywood, oriented strand board (OSB) is recommended. Structural hold downs must be attached to the studs and plates as per plans.
  5. Manufactured trusses must be used if over 20 feet in lieu of rafters.

NOTE: This handout shall serve as a guide by which to lay out a new accessory building, but upon submitted plans to the City Building Department, the City approved job copy of the plans shall be referenced. This handout does not override comments made on your plan review.

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