St. Louis Home Addition Permits 2026
St. Louis home addition permit fees, plan review, and required inspections for 2026.
St. Louis Home Addition permit basics
- Building department: City of St. Louis Building Division (Department of Public Safety)
- Department URL: https://www.stlouis-mo.gov/government/departments/public-safety/building/index.cfm
- Permit fee typical: $400 - $3,500 permit fee
- Plan review + approval: 7-15 business days for residential plan review
- Inspections required: 6-12 inspections (footing, framing, electrical, plumbing, mechanical, insulation, drywall, final)
St. Louis Home Addition common issues
Setback compliance, FAR (floor-area ratio), structural review required, sewer/water capacity may need upgrade.
St. Louis-specific permitting context
St. Louis is an independent city, legally separate from surrounding St. Louis County, so its Building Division permits and licenses apply only within city limits and differ from county jurisdictions next door. The city requires licensed master trades and contractor business licenses, and its position near the New Madrid seismic zone means Missouri code carries seismic detailing provisions.
Climate factors: Continental climate with hot humid summers, freeze-thaw winters, tornado and severe-storm exposure, and proximity to the New Madrid seismic zone.
Missouri licensing for Home Addition contractors
No statewide GC license; municipal (KC, St. Louis, Springfield) require local license - no statewide license, but St. Louis likely requires local registration.
Mechanics lien deadline in Missouri: 6 months from last work (4 months for laborers). Preliminary notice: 10-day notice of intent to file lien required.
St. Louis Home Addition sales tax
Missouri sales tax: 4.225% + local (~8.4% combined avg). Real property labor exempt. Contractor pays sales tax on materials at purchase.
Verify with the Missouri Department of Revenue.
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