Residential Building Permit

What is a Residential Building Permit?

A residential building permit is an integrated building permit for projects on residentially zoned property and would include projects such as:

  • Barns
  • Fences (over six feet tall)
  • Detached garages
  • Gazebo
  • Patio covers
  • Pavilions
  • Sheds
  • Structure elevation
  • Swimming pools and hot tubs
  • Pool barriers
  • Finished basements
  • Decks
  • Footing/foundation only
  • Foundation repairs
  • Retaining walls (over four feet tall)
  • Solar panels
  • Detached single-family residences
  • Display homes
  • Mobile home installations
  • Modular homes
  • Septic installation/repairs/certificates

Please note: When electric is included, a permit is required regardless of the size of the structure. The minimum service to be installed is one GFI receptacle, one light with wall switch and ever man door requires an interior switch and exterior light.

How Do I Apply?

To apply for a residential building permit, please visit the Building Construction Permit section of our Citizenserve Citizen Access Portal.

What Will I Need to Submit?

  • The names/business names of contractors that will be conducting work on the project
  • Building plans (PDF format preferred) showing footing/foundation detail, framing member sizes, header sizes, door and window locations 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.
  • A detailed plot plan (PDF) showing the location of your home and proposed building or structure on the lot. Show distances to property lines and keep in mind that structures may not be located over easements or septic systems.
  • Estimated cost of construction
  • If the property is incorporated into the Town of Weldon Spring, a land use permit from them will be required. You may contact them at 636-441-2110 for more information.

Fees and Plan Review

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 (PDF) 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 the ICC Building Safety Journal. The higher of these two estimates will by multiplied by 0.0073 (updated January 2020). This amount, or the minimum permit fee, 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.


At least one inspection is required. When the permit is issued, the necessary inspections required will be listed on your permit card. At the inspector’s discretion, some inspections may not be applicable to the particular permit in question. The inspector will note those inspections are "N/A" at a later date.

Inspections must be called in the Community Development office by 5 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.


If you have any questions, please contact the St. Charles County Building and Code Enforcement Division at 636-949-7345.