MISSOURI BUILDING PERMIT GUIDE

Missouri Building Permit Drawings: A Homeowner’s Guide to Permits, Plans & Construction

Planning a home addition, deck, garage, covered porch, basement remodel, or new house in Missouri?

One of the first things to understand is that there is no single permit process that applies everywhere in Missouri.

A project in Kansas City may have different requirements from the exact same project in Springfield, St. Louis County, Columbia, or a small rural community. Building codes, zoning rules, frost-depth requirements, plan requirements, and even whether engineered drawings are needed can change from one jurisdiction to another.

The good news is that most residential projects are relatively straightforward once you know who has jurisdiction over the property and what they expect to see on the drawings.

This guide explains some of the most important things Missouri homeowners should know before starting a permit project.

First Question: Do I Need a Building Permit in Missouri?

For most substantial residential construction, the answer is probably yes — but the final answer comes from your local city or county.

Projects that commonly require permits include:

• Home additions

• New houses

• Attached and detached garages

• Covered porches

• Decks

• Basement finishes

• Structural remodeling

• Garage conversions

• Accessory buildings

• Significant electrical, plumbing, or HVAC work

Very small projects may be exempt depending on the jurisdiction.

Here's an important Missouri-specific detail: don't assume the county is automatically your building department.

If your property is inside city limits, permits are often handled by the city. If you're outside municipal limits, the county may have jurisdiction — and requirements can be very different.

Before spending money on construction drawings, one of the first things we recommend is identifying the Authority Having Jurisdiction (AHJ) for your exact address.

Missouri Climate Design Factors

Missouri may look relatively uniform on a map, but construction conditions are not the same throughout the state.

Northern Missouri has colder winters and generally greater snow exposure. Southern Missouri tends to have lower snow loads, while southeastern Missouri introduces another interesting consideration: earthquake design associated with the New Madrid Seismic Zone.

Here are general ranges you may encounter:

Design Factor	Typical Missouri Range	Why It Matters
Frost Depth	Approximately 24"–36"+	Footings generally need adequate frost protection to prevent seasonal movement
Ultimate Wind Speed	Approximately 105–115+ mph	Affects roof connections, wall bracing, anchorage and structural design
Ground Snow Load	Approximately 10–30+ psf	Influences rafters, trusses, beams, headers and roof supports
Seismic Design	Generally lower in much of the state, potentially significant in southeastern Missouri	Can affect foundations, anchorage, wall bracing and structural connections
Climate Zone	Primarily IECC Climate Zones 4 and 5	Affects insulation, windows and other energy-code requirements

Important: These are general reference ranges, not values that should automatically be used for your project. The actual design criteria should be verified for the specific property and jurisdiction.

Missouri Has an Earthquake Zone — And It's a Big One

This surprises a lot of homeowners.

Southeastern Missouri is located near the New Madrid Seismic Zone, one of the most significant seismic regions in the central United States.

The area was responsible for a series of extremely powerful earthquakes in 1811 and 1812.

For most homeowners around Kansas City, Columbia, or northern Missouri, seismic design isn't usually the first issue that comes to mind when planning an addition or deck.

But in southeastern Missouri, seismic requirements can become much more important.

Depending on the location and construction type, plans may need to pay additional attention to:

• Foundation anchorage

• Wall bracing

• Structural connections

• Continuous load paths

• Shear resistance

This is a good example of why simply copying construction details from another Missouri project isn't always a good idea.

Missouri Weather Is Tough on Buildings

Missouri buildings experience a little bit of everything: heat, freezing temperatures, snow, thunderstorms, high winds, heavy rain, and tornadoes.

That makes good structural connections particularly important.

A house isn't simply a collection of walls sitting underneath a roof. Structurally, loads need to travel continuously from the roof all the way into the ground.

For example:

Roof → Rafters/Trusses → Walls or Beams → Posts → Foundation → Soil

This is called the load path.

It becomes particularly important when designing things like covered porches and decks.

Adding a roof over an existing deck might look like a simple project, but now the deck footings may be supporting concentrated roof loads they were never originally designed to carry.

That's why a building department may approve an uncovered deck design but request larger footings or additional structural information once a roof is added.

Thinking About Building a Deck? Pay Attention to the Footings

Decks are one of the most common residential projects we see in Missouri.

And one of the most common mistakes is focusing on the deck framing while forgetting what happens below ground.

Deck footings may need to account for:

• Frost depth

• Soil bearing capacity

• Tributary area

• Beam loads

• Roof loads if the deck is covered

• Post spacing

The footing for a simple uncovered deck may be very different from the footing required beneath a post supporting both a deck and a porch roof.

Missouri's freeze/thaw cycle also matters.

A shallow footing can potentially move as moisture in the soil freezes and expands. This is why frost protection requirements are important even for relatively small outdoor structures.

Basements Are Everywhere in Missouri — And They Create Their Own Permit Issues

Unlike many parts of the southern United States, basements are extremely common in Missouri.

That means basement finishing projects are also common permit applications.

Turning an unfinished basement into living space may seem straightforward, but building departments typically look at more than just the new walls.

If you're adding a bedroom, for example, you may need to consider:

• Emergency escape and rescue openings

• Minimum ceiling height

• Smoke alarms

• Carbon monoxide alarms

• Electrical receptacle requirements

• HVAC supply and return

• Insulation

• Stair requirements

A Common Basement Mistake

Putting a bed in a room doesn't automatically make it a legal bedroom.

If you're creating a basement bedroom, the room generally needs to meet applicable requirements for emergency escape and rescue.

That often means verifying the size and configuration of the window and window well — not simply labeling the room BEDROOM on the floor plan.

Want to Remove a Wall? Find Out What It's Holding Up First

Open-concept remodeling is extremely popular.

But before removing a wall between a kitchen, dining room, and living room, you need to determine whether it's load-bearing.

A load-bearing wall may support:

• Floor joists

• Roof rafters

• Roof trusses

• Beams

• Another bearing wall above

If it is bearing, removing it usually means replacing the wall with a properly sized beam.

But beam sizing is only part of the problem.

The loads at each end of the beam also need somewhere to go.

For example:

Beam → Post → Floor System → Foundation

Sometimes that means adding posts, beams below, or new footings in the basement or crawlspace.

This is one of the reasons a project that looks like “just remove this wall” can turn into a structural project.

Kansas City Area: One Metro, Many Building Departments

If you're building around Kansas City, location matters more than you might expect.

The metro area includes jurisdictions such as:

• Kansas City

• Independence

• Lee's Summit

• Blue Springs

• Liberty

• Jackson County

• Clay County

• Platte County

And that's before crossing the state line into Kansas.

Two houses only a few miles apart can potentially fall under different building departments, different code editions, and different local amendments.

So if your contractor tells you:

“We did the same thing on another house nearby.”

That's useful experience — but it doesn't necessarily mean your permit requirements will be identical.

St. Louis Can Be Even More Jurisdiction-Specific

The St. Louis area is especially interesting because of the large number of municipalities within the metropolitan area.

Depending on the property, permitting may involve St. Louis, St. Louis County, or an individual municipality.

That makes confirming the exact jurisdiction particularly important before preparing drawings.

Around St. Louis, we recommend confirming early:

• Who issues the building permit?

• Which building code edition applies?

• Is zoning reviewed separately?

• Are structural calculations required?

• Are there municipality-specific forms?

• Does the property fall within a historic district?

• Are there additional subdivision or HOA requirements?

Knowing these answers before designing can save a surprising amount of time later.

Building Near the Lake of the Ozarks? Your Site May Matter as Much as Your House

Lake properties can introduce challenges that don't exist on a typical suburban lot.

A lake house or addition may be built on a significantly sloped property.

That can affect:

• Foundation elevations

• Walkout basements

• Retaining walls

• Deck posts

• Footing heights

• Drainage

• Grading

• Finished floor elevations

A large elevated deck overlooking the lake, for example, may require considerably more structural attention than a deck only a few feet above grade.

Tall posts increase lateral movement and can make bracing and connection details much more important.

Detached Garages, Workshops & Pole Buildings

Missouri properties often have enough space for substantial accessory buildings.

Common projects include:

• Detached garages

• Workshops

• Storage buildings

• Barn-style structures

• RV garages

• Pole buildings

Before designing one, check the zoning rules.

The building itself may comply perfectly with the building code and still be rejected because of zoning.

Common zoning limitations include:

• Required setbacks

• Maximum building height

• Maximum accessory building area

• Lot coverage

• Location relative to the main house

• Easements

A 30' × 40' garage isn't very useful if the zoning setback only leaves room for a 24' × 30' structure.

Check the buildable area first — then design the building.

What About Tornadoes?

Missouri is well known for severe storms and tornadoes.

However, a standard residential building permit does not automatically mean your house or addition is being designed as a tornado shelter.

Tornado-resistant safe rooms are a specialized type of construction.

If you're considering a dedicated storm shelter or safe room, it should be specifically designed for that purpose rather than assuming a basement room or reinforced-looking space provides equivalent protection.

For homeowners already planning a new house or major addition, it can be worth discussing this during the design phase rather than trying to retrofit one later.

Do Missouri Residential Plans Need an Engineer's Stamp?

Not necessarily.

This is another common misconception.

Many conventional residential projects can potentially be designed using the prescriptive provisions of the locally adopted residential code without requiring a structural engineer for the entire building.

However, engineering may become necessary when the project goes beyond those prescriptive limits.

Examples may include:

• Long-span beams

• Large openings

• Unusual roof structures

• Significant point loads

• Complex foundations

• Tall retaining walls

• Non-standard framing

• Large elevated decks

• Unusual lateral loading conditions

Engineered products such as roof trusses and LVLs may also come with calculations or documentation from their manufacturer or supplier.

The key is not assuming that every project needs engineering or that no project needs engineering.

It depends on the design and the jurisdiction.

What Should Be Included in a Missouri Permit Drawing Set?

The exact package depends on the project, but a residential permit set may include:

Site Plan

Shows where the proposed construction sits on the property and its relationship to:

• Property lines

• Existing buildings

• Setbacks

• Driveways

• Easements

• Proposed structures

Floor Plans

Typically show:

• Room dimensions

• Doors and windows

• Wall locations

• Fixtures

• Stairs

• Structural elements

• Construction notes

Exterior Elevations

Show what the building will look like from the exterior, including:

• Building heights

• Roof slopes

• Windows and doors

• Exterior materials

• Grade relationships

Foundation Plan

May show:

• Footings

• Foundation walls

• Slabs

• Piers

• Posts

• Beams

• Foundation dimensions

Roof & Framing Information

Depending on the project:

• Rafters

• Roof trusses

• Beams

• Headers

• Joists

• Posts

• Structural connections

Building Sections & Details

These drawings explain how the building actually goes together.

They can show:

• Foundation construction

• Floor assemblies

• Wall framing

• Roof framing

• Insulation

• Connections

• Vertical dimensions

For permitting, the goal isn't simply to make the plans look professional.

The drawings should provide enough information for the reviewer to understand what is being built and how it will comply with the applicable requirements.

5 Things to Check Before Paying for Permit Drawings

A little preparation can save a lot of redesign work.

Before starting your Missouri project, try to confirm:

1. Your exact permitting jurisdictionFind out whether the city or county handles your permit.

2. Your zoning setbacksMake sure the project physically fits within the buildable area.

3. Whether you have a surveyThis is particularly useful for additions, garages, decks, and other exterior projects.

4. Whether your neighborhood has an HOABuilding department approval and HOA approval are completely separate things.

5. Whether engineering is requiredDon't automatically pay for engineering before knowing you need it — but don't assume a complicated structural project can be handled prescriptively either.

Common Missouri Permit Mistakes

Some of the most avoidable permit problems happen before the drawings are even submitted.

Designing Before Checking Setbacks

You finish designing your dream garage and then discover it's three feet inside the required setback.

Assuming an Existing Deck Can Support a Roof

Adding a roof changes the loads dramatically. Existing posts and footings may need to be evaluated.

Removing a Bearing Wall Without Following the Load Path

A large beam doesn't solve anything if there isn't adequate support beneath its ends.

Using Plans From Another Jurisdiction

Even neighboring Missouri cities may use different code editions or amendments.

Ignoring Drainage

A new addition, garage, patio, or driveway changes how water moves across the property. Some jurisdictions pay close attention to this during review.

Common Building Codes Used in Missouri

Depending on the jurisdiction, Missouri building departments may adopt versions of:

• IRC — International Residential Code

• IBC — International Building Code

• IECC — International Energy Conservation Code

• IPC — International Plumbing Code

• IMC — International Mechanical Code

• NEC — National Electrical Code

The important word here is “depending.”

Code editions and amendments are not necessarily identical statewide.

That's why our first step with a Missouri project is to identify the jurisdiction and research the locally applicable requirements rather than simply applying one generic Missouri standard.

What Happens If the City Sends Plan Review Comments?

Don't panic.

Plan check comments are a normal part of the permitting process.

A reviewer may ask for:

• A missing construction detail

• Additional dimensions

• Beam or header information

• Foundation clarification

• Energy information

• Revised site information

• Structural calculations

• Additional notes

Receiving comments doesn't necessarily mean the plans were “rejected.”

Usually, the reviewer is identifying items that need clarification or correction before the permit can be issued.

We assist our clients with updating the drawings and responding to permit review comments throughout the approval process.

Areas We Serve in Missouri

We prepare residential permit and construction drawings for projects throughout Missouri, including:

• Kansas City

• St. Louis

• Springfield

• Columbia

• Independence

• Lee's Summit

• St. Charles

• Jefferson City

• Blue Springs

• Liberty

• Joplin

• Branson

• Jackson County

• Clay County

• Platte County

• St. Louis County

• St. Charles County

• Lake of the Ozarks communities

We can also assist with projects in smaller Missouri cities and counties.

Because local requirements vary, we research the permitting jurisdiction for the specific property rather than relying on a generic statewide checklist.

Planning a Project in Missouri?

If you're considering a deck, covered porch, home addition, basement remodel, garage, accessory building, or new home, you don't need to figure out the entire permitting process yourself before contacting us.

To get started, send us:

• Project address

• A short description of what you want to build

• Any sketches you already have

• Photos of the existing house or site

• A survey, if available

• Any information you've already received from the city or county

Even a hand sketch is usually enough to start the conversation.

We'll review the project location, determine the applicable permitting jurisdiction, identify the likely drawing requirements, and help you understand what will be needed before moving forward.

Have a project in Missouri? Send us the address and a quick description of what you're planning, and we'll take it from there.