Columbia, MO Building Safety: Building Permits (2026)
Key Facts
- Replacement deck, same size
- Not a 'structure': no permit trigger
- New or enlarged deck
- Counts as a structure
- Accessory structure cap
- 3,000 sq ft, 24 ft height
- Rear yard limit
- Max 30% of rear yard
- Patio threshold
- Not separately addressed in code
Summary
Columbia, Missouri treats a new or enlarged deck as a zoning 'structure' requiring a permit, but exempts a like-for-like replacement deck of the same size from that classification.
R202 Structure. Add following exception:
Exception: For existing decks being replaced, the same size will not be considered a structure for zoning purposes.
Table 301.2(1). The following values shall be inserted into Table R301.2(1):
Ground Snow Load - 20; Wind Speed (mph) - 115; Topographic Effects - No; Special Wind Region - No; Windborne Debris Zone - No; Seismic Design Category - B, Weathering - Yes Severe; Frost Line Depth - 30-inches; Termite - Moderate to Heavy; Winter Design Temperature - +4 Degrees Fahrenheit; Ice Barrier Underlayment Required - No; Flood Hazards - As regulated by City of Columbia Ordinance; Air Freezing Index - 0 to 1,500; Mean Annual Temperature - 55 degrees Fahrenheit.
Elevation - 778; Latitude - 39 degrees; Winter Heating - 4 Degrees; Summer Cooling - 94 Degrees; Altitude Correction Factor - No; Indoor Design Temperature - 72 Degrees; Design Temperature Cooling - 75 Degrees; Heating Temperature Difference - 68 Degrees; Cooling Temperature Difference - 19 Degrees; Wind Velocity Heating - 25; Wind Velocity Cooling - 7.5; Coincident Wet Bulb - 78; Daily Range - Medium; Winter Humidity - 20; Summer Humidity - 60.
Table R301.5. Add note g.4.: Must also include a vertical egress component.
R302.5.1 Opening protection. Delete from the last sentence: "equipped with a self-closing or automatic-closing device".
R303.6 Outside opening protection. At the end of the paragraph, add the following:
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 138).
Full Breakdown
Columbia adopted the 2018 International Residential Code and locally amended its definitions section (§ 6-66). The amendment adds an exception to the code's 'Structure' definition: an existing deck being replaced at the same size is not treated as a structure for zoning purposes, so it can skip the structure-level permit and setback review that applies to new decks. A deck built new or enlarged does count as a structure, capped, like other accessory structures, at 3,000 square feet, three stories or 24 feet in height, and no more than 30 percent of the required rear yard (§ 6-66, R202). The code text located for this topic does not set a separate permit threshold specific to patios.
Violations & Fines
Building or enlarging a deck without the required permit and inspections is enforced the same as any unpermitted structure under the residential code, § 6-66, with fines up to $1,000 per day under § R113.4.
Frequently Asked Questions
Do I need a permit to replace my deck in Columbia, Missouri?
What about building a brand-new deck or a patio?
Sources & Official References
Other rules in Columbia
Compare Columbia to another location·View the Missouri building safety overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.