Accessory Structure Permit

View this information and building plan examples in PDF format.

How Do I Apply? 

Please visit the Building Construction Permit section of our Citizenserve Citizen Access Portal to apply online.



When is an Accessory Structure Permit Required? 


Accessory structures are free-standing, separate buildings, which are devoted exclusively to an accessory use. In residential zoning districts accessory buildings include, but are not limited to, fences, a greenhouse, lean-to, storage shed, swimming pool cabana, gazebo, detached carports and garages.

No more than two accessory structures and one principal structure may be erected on a lot. Generally the total size of all accessory structures may not exceed one-half the area of the ground floor level of the principal building on the lot. Please consult the Unified Development Ordinance or the Planning and Zoning Division for the specific zoning district regulations where the subject property is located.

Metal siding is prohibited in “R” residential zoning districts.

An accessory structure permit is required:

  • If a proposed accessory structure is greater than 120 square feet, a building permit is required. 
  • If the structure will have electricity, a permit is required regardless of the size of the structure. 
  • If your property is located in the floodplain, a Floodplain Permit will be required for any structure proposed, regardless of size. 
  • If the proposed structure is 120 square feet or less, a building permit is not required; however, the structure must meet the required property line setbacks. 

Types of Accessory Structure Permits:

  • Barn, including Pole Building
  • Shed
  • Detached Garage
  • Retaining Walls
  • Fence/Barrier
    • Applications for fences over 6 feet in height must include engineering.
    • The applicant is required to stake or flag the location on the ground of all property pins (markers) for all property lines nearest to the fence.
    • Fences must conform to the fence standards of Section 405.415 of the Unified Development Ordinance.
  • Pavilion/Gazebo
  • Miscellaneous Building

Where Can I Locate My Accessory Structure?


Generally, the structure must be located in a way such that the edge of the building will be no closer than seven (7) feet from the side and rear property lines and no closer than fifty (50) feet from the front property line. The structure must be located a minimum of ten (10) feet from the residence. Please consult the Unified Development Ordinance or contact the Planning and Zoning Department for the specific zoning district regulations where the subject property is located. 

Please note that an accessory structure is not allowed to be located in any type of easement, over a septic system, or over any property line.

What Will I Need to Submit?


  • Building plans (PDF format preferred) showing footing/foundation detail, framing member sizes, header sizes, door and window location and sizes, truss or rafter design, flooring detail, and any electrical or plumbing. Also include floor plan, wall cut detail, elevations, and any applicable stair details. 
  • When electric is included, one of the following is required: 1 (one) GFI receptacle, 1 (one) light with wall switch, and every man door requires an interior switch and exterior light. 
  • A detailed plot plan showing the location of your home and proposed structure on the lot. Show distances to property lines and keep in mind that structures may not be located over easements or septic systems. 
The plan review process typically takes about 10 working days. When the permit is ready, you will be notified via email the amount of the permit fee. This fee is based on the cost of construction. 

Fees & Plan Review


Building Permit Fees (PDF)

The plan review process typically takes about 10 working days. When the permit is ready, you will be notified via email that the permit is ready for pick up as well as the final amount of the permit fee. 

Building permit fees are based on cost of construction. At the time of application, you will provide us with your estimated cost of construction and our plan reviewers will calculate an estimated cost of construction per ICC Building Safety Journal. The higher of these two estimates will be multiplied by 0.73%; this amount, or the minimum permit amount, whichever is higher, is the building permit fee that will be charged. There may be other fees associated with your permit, such as floodplain permit fees, land disturbance fees, and other fees as applicable. 

Electric Service 


If electric service is provided, then an electrical permit is required regardless of the size of the structure. The minimum service to be installed is: 1 (one) GFI receptacle, 1 (one) light with wall switch, and every man door requires an interior switch and exterior light. 


Inspections


All buildings that require a building permit will need to be inspected. Inspections must be called into the office by 3 p.m. the business day prior to your requested inspection date. To schedule your inspection, call 636-949-7345. If it is necessary to cancel or change your inspection, please do so as soon as possible. Also, please remember to post your permit so that it is visible from the street. The first inspection will be performed when the piers/footings have been excavated. The inspector will measure these for proper depth, size, soil condition, location on the lot and verify reinforcement (if any). The final inspection will be performed when the structure is complete.


Questions?


Please contact the St. Charles County Building and Code Enforcement Division at 636-949-7345 or bce@sccmo.org.