Do I need a permit to build a deck in St. Louis, MO?

Yes. In St. Louis, any deck attached to your home or elevated more than 30 inches above grade requires a building permit and a site plan. The site plan must show the deck's location relative to all property lines so the Building Division can confirm it meets setback requirements for your zoning district. You will also need construction drawings showing the deck's framing, ledger attachment, and footing design. Inspections are required at the footing stage and at final completion. Skipping the permit can result in stop-work orders, fines, and difficulty selling your home if the unpermitted structure is discovered during a title search or home inspection.

What does St. Louis require on a residential site plan?

A residential site plan submitted to the City of St. Louis Building Division must show the property's lot dimensions and boundaries, the location and footprint of all existing structures on the lot, the proposed improvement drawn to scale, the distance from the proposed structure to each property line (setbacks), any utility or drainage easements, driveways and walkways, and a north arrow with a stated scale. For projects near the Mississippi or Missouri Rivers, the plan may also need to reference the Base Flood Elevation. Plans that are not drawn to a consistent scale or that omit setback dimensions are among the most common reasons applications are returned without review.

How much does a building permit cost in St. Louis?

Permit fees in St. Louis are generally calculated based on the estimated construction value of the project. As of 2026, residential permit fees typically start around $50 to $100 for small projects like sheds or fences and can reach several hundred to several thousand dollars for larger additions or new construction. There are also separate plan review fees for projects that require formal review. Historic district projects may incur additional fees for the Cultural Resources Office review. You can get a fee estimate by contacting the City of St. Louis Building Division directly at (314) 622-3313 or by using the city's online permit portal to calculate fees before submission.

How long does it take to get a building permit approved in St. Louis?

The timeline depends on the complexity of your project. Simple permits for fences, small sheds, or minor repairs may be approved over the counter the same day you submit, or within a few business days through the online portal. Standard residential projects like decks, pools, and additions typically go through formal plan review, which takes 10 to 20 business days. Projects that require additional approvals, such as historic district review through the Cultural Resources Office, a variance from the Board of Adjustment, or floodplain compliance documentation, can take 4 to 8 weeks or longer. Submitting a complete, accurate application with a well-drawn site plan is the single best way to avoid delays.

Can I draw my own site plan in St. Louis, or do I need a licensed surveyor?

For most standard residential permits in St. Louis, you are not required to hire a licensed surveyor or engineer to prepare your site plan. Homeowners and contractors can draw their own site plans as long as the drawing is to scale, includes all required information, and accurately reflects the property dimensions. Using your property survey (which you likely received at closing) as a reference for lot dimensions is a common and accepted approach. However, if your project involves structural engineering, is located in a floodplain, or requires a variance, professional drawings or a certified elevation certificate may be required. Tools like Site Plan Creator make it easy to produce a compliant, professional-looking site plan without specialized drafting software.

What are the setback requirements for residential properties in St. Louis?

Setbacks in St. Louis vary by zoning district. For typical single-family residential zones, front yard setbacks generally range from 20 to 35 feet from the front property line, often aligned with the prevailing setback of neighboring homes on the block. Side yard setbacks are commonly 3 to 5 feet for interior lots, with corner lots requiring a larger setback of 10 to 15 feet on the street-facing side. Rear yard setbacks typically range from 25 to 35 feet, though detached accessory structures like sheds and garages are often permitted within 3 to 5 feet of the rear and side lot lines. Always confirm the exact setbacks for your zoning district with the City of St. Louis Planning and Urban Design Agency before finalizing your site plan.

What happens if I build without a permit in St. Louis?

Building without a required permit in St. Louis can have serious consequences. The Building Division has the authority to issue a stop-work order, which halts all construction immediately. You may be required to obtain a retroactive permit, which often involves opening up completed work for inspection. Fines and penalty fees can be assessed, sometimes doubling or tripling the original permit fee. Unpermitted work can also create problems when you sell your home, as buyers' lenders and inspectors routinely flag unpermitted structures. In historic districts, unpermitted exterior changes can trigger additional enforcement actions through the Cultural Resources Office. It is always less expensive and less stressful to pull the permit before breaking ground.

Does my St. Louis property fall in a floodplain, and how does that affect my permit?

Portions of St. Louis near the Mississippi and Missouri Rivers fall within FEMA-designated Special Flood Hazard Areas (SFHAs), commonly called the 100-year floodplain. If your property is in an SFHA, any new construction or substantial improvement must comply with the city's floodplain management ordinance. This typically means the finished floor elevation of habitable space must be at or above the Base Flood Elevation (BFE) shown on the FEMA Flood Insurance Rate Map (FIRM). A certified elevation certificate from a licensed surveyor may be required as part of your permit application. You can check your flood zone status at the FEMA Flood Map Service Center at msc.fema.gov. Floodplain compliance adds time and cost to a project but is essential for maintaining flood insurance eligibility.

Are ADUs (accessory dwelling units) allowed in St. Louis, and what permits do they require?

Yes, accessory dwelling units are permitted in many St. Louis residential zoning districts, including carriage houses, basement apartments, and detached backyard cottages. ADU projects require a full building permit and a detailed site plan showing the ADU's location, setbacks, lot coverage, and relationship to the primary dwelling. St. Louis has specific regulations on the maximum size of ADUs relative to the primary home, owner-occupancy requirements in some districts, and parking requirements. If the property is in a historic district, the ADU design must also receive a Certificate of Appropriateness from the Cultural Resources Office. ADU rules have been evolving in Missouri, so it is worth checking current city zoning ordinances or consulting the Building Division before finalizing your plans.

Where do I submit a permit application in St. Louis, MO?

As of 2026, the City of St. Louis Building Division accepts permit applications both online and in person. The online permitting portal allows homeowners and contractors to submit applications, upload site plans and construction documents, pay fees, and track review status without visiting City Hall. For in-person submissions, the Building Division is located at 1200 Market Street, Room 425, St. Louis, MO 63103. Over-the-counter review for simple projects is available in person during business hours. For projects requiring historic district review, you will also need to submit separately to the Cultural Resources Office. Calling the Building Division at (314) 622-3313 before your first submission is a good way to confirm current procedures and required documents.

Site Plan Requirements in St. Louis, MO (Permit Guide)

By Site Plan Creator Team • June 9, 2026

St. Louis, Missouri has detailed residential permit and site plan requirements that homeowners must navigate before starting most outdoor or structural projects. From historic neighborhoods to floodplain zones along the Mississippi, local rules add layers of complexity. This guide walks you through everything you need to know to get your St. Louis project approved.

Site plan requirements for residential properties in St. Louis, Missouri

Residential Site Plans and Permits in St. Louis, MO

St. Louis is one of America's most architecturally rich cities, home to Victorian-era neighborhoods like Lafayette Square, mid-century bungalows in south city, and contemporary infill development across the region. Whether you are adding a deck to a Soulard rowhouse or building an accessory dwelling unit (ADU) in University City, the City of St. Louis takes residential permitting seriously. The city's Department of Public Safety, through its Building Division, enforces the International Building Code (IBC) and local zoning ordinances that govern nearly every construction project on private residential property. Understanding what a site plan is, when you need one, and how to prepare a compliant application can save you weeks of delays and costly rework.

What Is a Residential Site Plan and Why Does St. Louis Require One?

A residential site plan is a scaled, bird's-eye drawing of your property that shows the lot boundaries, existing structures, proposed improvements, setbacks from property lines, driveways, utility easements, and other relevant features. St. Louis requires site plans for most permit applications because reviewers need to verify that your project complies with zoning district regulations before construction begins. Without an accurate site plan, the Building Division cannot confirm that a new deck, pool, or addition respects required setbacks or that impervious surface coverage stays within allowable limits.

Site plans do not need to be engineering masterpieces, but they must be drawn to scale and include enough detail to answer the reviewer's questions on the first pass. Many homeowners use tools like Site Plan Creator to produce professional-quality drawings without hiring a surveyor for every small project.

Residential Permit Triggers in St. Louis

The following improvements almost always require a building permit and an accompanying site plan in St. Louis:

Decks and porches: Any deck attached to the home or elevated more than 30 inches above grade requires a permit.
Detached sheds and garages: Structures larger than 120 square feet (and in some zoning districts, any permanent structure) require a permit.
Swimming pools: Both in-ground and above-ground pools deeper than 24 inches require a permit, plus electrical and fence inspections.
Fences: Fences over 6 feet in height, or any fence in a front yard exceeding 4 feet, typically require a permit. Historic districts may have stricter rules.
Additions: Any addition to a home's footprint, including sunrooms, bump-outs, and enclosed porches, requires a full permit with site plan.
ADUs and carriage houses: Accessory dwelling units are permitted in many St. Louis zoning districts but must meet specific lot coverage and setback requirements.
Driveways and impervious surfaces: New driveways or significant expansions may require a grading or stormwater permit, especially in flood-prone areas.
HVAC, electrical, and plumbing: Mechanical work typically requires separate trade permits even when bundled with a larger project.

Local Zoning Quirks and Notable Considerations

St. Louis has several local factors that make permitting more complex than in a typical suburban city:

Historic Districts: St. Louis has numerous locally designated historic districts, including Compton Heights, Central West End, and the Anheuser-Busch Historic District. Projects in these areas must receive approval from the Cultural Resources Office before a building permit is issued. Exterior alterations, additions, and even fence replacements may require a Certificate of Appropriateness.

Floodplain Regulations: Large portions of St. Louis near the Mississippi and Missouri Rivers fall within FEMA-designated Special Flood Hazard Areas (SFHAs). Projects in these zones must comply with the city's floodplain management ordinance, which may require finished floor elevations to be set above the Base Flood Elevation (BFE). You can check your property's flood zone status at the FEMA Flood Map Service Center.

Lot Coverage Limits: Most residential zoning districts in St. Louis cap the total impervious surface (roofs, driveways, patios, and other hard surfaces) at a percentage of the lot area. Exceeding this limit requires a variance from the Board of Adjustment.

Neighborhood Stabilization Overlays: Some areas of the city have overlay zoning that restricts demolition, sets design standards, or requires additional review. Always check the city's zoning map before assuming standard district rules apply.

HOA Rules: Many St. Louis-area neighborhoods, particularly in the county and suburban municipalities, have homeowners associations with their own design review requirements. HOA approval does not replace city permits, and city permits do not override HOA rules.

Typical Setback Requirements in St. Louis

Setbacks in St. Louis vary by zoning district, but the following ranges are common for single-family residential zones:

Front yard setback: 20 to 35 feet from the front property line (often matched to the prevailing setback on the block)
Side yard setback: 3 to 5 feet for interior lots; corner lots may require 10 to 15 feet on the street side
Rear yard setback: 25 to 35 feet, though accessory structures may be permitted closer to the rear lot line
Accessory structures: Detached garages and sheds are often allowed within 3 to 5 feet of the rear and side property lines in residential districts

Always verify the exact setbacks for your zoning district using the City of St. Louis Zoning Code before finalizing your site plan.

The St. Louis Permit Submission Process

Step 1: Determine Your Zoning District

Visit the City of St. Louis Planning and Urban Design Agency's online resources or contact the Building Division to confirm your property's zoning classification. This determines which setbacks, lot coverage limits, and use regulations apply to your project.

Step 2: Prepare Your Site Plan

Draw your site plan to scale, showing lot dimensions, all existing structures, the proposed improvement, setbacks from all property lines, driveways, utility easements, and any relevant natural features (trees, slopes, or drainage). Tools like Site Plan Creator make it straightforward to produce a compliant drawing.

Step 3: Assemble Your Application Package

A typical St. Louis residential permit application includes the completed permit application form, your site plan, construction drawings or specifications for the proposed work, and payment of the applicable permit fee. Historic district projects also require the Cultural Resources Office submittal.

Step 4: Submit to the Building Division

As of 2026, the City of St. Louis Building Division accepts permit applications both in person at City Hall and through its online permitting portal. Smaller projects like sheds and fences may be eligible for over-the-counter review, while larger additions and ADUs typically go through a formal plan review process.

Step 5: Plan Review and Approval

Over-the-counter reviews can be completed the same day for simple projects. Standard residential plan reviews typically take 10 to 20 business days. Projects requiring historic review, variance approval, or floodplain analysis can take 4 to 8 weeks or longer. Once approved, you will receive your permit and can schedule required inspections.

Common Reasons Site Plan Applications Get Rejected

Missing or inaccurate dimensions: Setback distances not shown, or dimensions that do not match the described lot size.
No scale or incorrect scale: Drawings that are not drawn to a consistent, stated scale are routinely rejected.
Incomplete structure labeling: Failure to label existing structures, proposed structures, or property lines clearly.
Lot coverage not calculated: Not showing or calculating total impervious surface coverage when required.
Missing easements: Utility, drainage, or access easements not shown on the plan.
Historic review not completed: Submitting to the Building Division before obtaining a Certificate of Appropriateness for a historic district property.
Flood zone compliance missing: Projects in SFHAs submitted without the required elevation certificate or floodplain compliance documentation.

Get Your St. Louis Site Plan Right the First Time

Navigating St. Louis's permitting landscape is much easier when your site plan is accurate, complete, and professionally presented from the start. Site Plan Creator is built for homeowners and contractors who need a clean, to-scale site plan quickly, without the cost of a full survey or drafting service. Start your St. Louis site plan today and move your project forward with confidence.

Frequently Asked Questions

Do I need a permit to build a deck in St. Louis, MO?: Yes. In St. Louis, any deck attached to your home or elevated more than 30 inches above grade requires a building permit and a site plan. The site plan must show the deck's location relative to all property lines so the Building Division can confirm it meets setback requirements for your zoning district. You will also need construction drawings showing the deck's framing, ledger attachment, and footing design. Inspections are required at the footing stage and at final completion. Skipping the permit can result in stop-work orders, fines, and difficulty selling your home if the unpermitted structure is discovered during a title search or home inspection.
What does St. Louis require on a residential site plan?: A residential site plan submitted to the City of St. Louis Building Division must show the property's lot dimensions and boundaries, the location and footprint of all existing structures on the lot, the proposed improvement drawn to scale, the distance from the proposed structure to each property line (setbacks), any utility or drainage easements, driveways and walkways, and a north arrow with a stated scale. For projects near the Mississippi or Missouri Rivers, the plan may also need to reference the Base Flood Elevation. Plans that are not drawn to a consistent scale or that omit setback dimensions are among the most common reasons applications are returned without review.
How much does a building permit cost in St. Louis?: Permit fees in St. Louis are generally calculated based on the estimated construction value of the project. As of 2026, residential permit fees typically start around $50 to $100 for small projects like sheds or fences and can reach several hundred to several thousand dollars for larger additions or new construction. There are also separate plan review fees for projects that require formal review. Historic district projects may incur additional fees for the Cultural Resources Office review. You can get a fee estimate by contacting the City of St. Louis Building Division directly at (314) 622-3313 or by using the city's online permit portal to calculate fees before submission.
How long does it take to get a building permit approved in St. Louis?: The timeline depends on the complexity of your project. Simple permits for fences, small sheds, or minor repairs may be approved over the counter the same day you submit, or within a few business days through the online portal. Standard residential projects like decks, pools, and additions typically go through formal plan review, which takes 10 to 20 business days. Projects that require additional approvals, such as historic district review through the Cultural Resources Office, a variance from the Board of Adjustment, or floodplain compliance documentation, can take 4 to 8 weeks or longer. Submitting a complete, accurate application with a well-drawn site plan is the single best way to avoid delays.
Can I draw my own site plan in St. Louis, or do I need a licensed surveyor?: For most standard residential permits in St. Louis, you are not required to hire a licensed surveyor or engineer to prepare your site plan. Homeowners and contractors can draw their own site plans as long as the drawing is to scale, includes all required information, and accurately reflects the property dimensions. Using your property survey (which you likely received at closing) as a reference for lot dimensions is a common and accepted approach. However, if your project involves structural engineering, is located in a floodplain, or requires a variance, professional drawings or a certified elevation certificate may be required. Tools like Site Plan Creator make it easy to produce a compliant, professional-looking site plan without specialized drafting software.
What are the setback requirements for residential properties in St. Louis?: Setbacks in St. Louis vary by zoning district. For typical single-family residential zones, front yard setbacks generally range from 20 to 35 feet from the front property line, often aligned with the prevailing setback of neighboring homes on the block. Side yard setbacks are commonly 3 to 5 feet for interior lots, with corner lots requiring a larger setback of 10 to 15 feet on the street-facing side. Rear yard setbacks typically range from 25 to 35 feet, though detached accessory structures like sheds and garages are often permitted within 3 to 5 feet of the rear and side lot lines. Always confirm the exact setbacks for your zoning district with the City of St. Louis Planning and Urban Design Agency before finalizing your site plan.
What happens if I build without a permit in St. Louis?: Building without a required permit in St. Louis can have serious consequences. The Building Division has the authority to issue a stop-work order, which halts all construction immediately. You may be required to obtain a retroactive permit, which often involves opening up completed work for inspection. Fines and penalty fees can be assessed, sometimes doubling or tripling the original permit fee. Unpermitted work can also create problems when you sell your home, as buyers' lenders and inspectors routinely flag unpermitted structures. In historic districts, unpermitted exterior changes can trigger additional enforcement actions through the Cultural Resources Office. It is always less expensive and less stressful to pull the permit before breaking ground.
Does my St. Louis property fall in a floodplain, and how does that affect my permit?: Portions of St. Louis near the Mississippi and Missouri Rivers fall within FEMA-designated Special Flood Hazard Areas (SFHAs), commonly called the 100-year floodplain. If your property is in an SFHA, any new construction or substantial improvement must comply with the city's floodplain management ordinance. This typically means the finished floor elevation of habitable space must be at or above the Base Flood Elevation (BFE) shown on the FEMA Flood Insurance Rate Map (FIRM). A certified elevation certificate from a licensed surveyor may be required as part of your permit application. You can check your flood zone status at the FEMA Flood Map Service Center at msc.fema.gov. Floodplain compliance adds time and cost to a project but is essential for maintaining flood insurance eligibility.
Are ADUs (accessory dwelling units) allowed in St. Louis, and what permits do they require?: Yes, accessory dwelling units are permitted in many St. Louis residential zoning districts, including carriage houses, basement apartments, and detached backyard cottages. ADU projects require a full building permit and a detailed site plan showing the ADU's location, setbacks, lot coverage, and relationship to the primary dwelling. St. Louis has specific regulations on the maximum size of ADUs relative to the primary home, owner-occupancy requirements in some districts, and parking requirements. If the property is in a historic district, the ADU design must also receive a Certificate of Appropriateness from the Cultural Resources Office. ADU rules have been evolving in Missouri, so it is worth checking current city zoning ordinances or consulting the Building Division before finalizing your plans.
Where do I submit a permit application in St. Louis, MO?: As of 2026, the City of St. Louis Building Division accepts permit applications both online and in person. The online permitting portal allows homeowners and contractors to submit applications, upload site plans and construction documents, pay fees, and track review status without visiting City Hall. For in-person submissions, the Building Division is located at 1200 Market Street, Room 425, St. Louis, MO 63103. Over-the-counter review for simple projects is available in person during business hours. For projects requiring historic district review, you will also need to submit separately to the Cultural Resources Office. Calling the Building Division at (314) 622-3313 before your first submission is a good way to confirm current procedures and required documents.

How to Create a Site Plan in St. Louis

Confirm Your Zoning District: Before drawing anything, look up your property's zoning classification using the City of St. Louis Planning and Urban Design Agency's zoning map or by contacting the Building Division. Your zoning district determines the setbacks, lot coverage limits, and permitted uses that apply to your project. Properties in historic district overlays or floodplain zones will have additional requirements that must be addressed early in the planning process.
Gather Your Property Documents: Locate your property survey, deed, and any recorded easements. Your survey will show the lot dimensions and boundary lines you need to draw an accurate site plan. If you do not have a survey, you may be able to obtain one from your county recorder's office or title company. Knowing the exact dimensions of your lot is essential before you can correctly calculate setbacks and lot coverage for your St. Louis permit application.
Draw Your Site Plan to Scale: Create a scaled drawing that shows your lot boundaries, all existing structures, the proposed improvement, setback distances from every property line, driveways, walkways, utility easements, and a north arrow. The plan must clearly label all elements and state the drawing scale. Site Plan Creator is a fast, affordable tool that helps St. Louis homeowners produce a clean, professional site plan that meets Building Division requirements without hiring a drafter.
Obtain Any Required Pre-Approvals: If your property is in a St. Louis historic district, submit your project to the Cultural Resources Office and obtain a Certificate of Appropriateness before applying for a building permit. If your lot is in a FEMA Special Flood Hazard Area, gather your elevation certificate and floodplain compliance documentation. HOA approval, if required, should also be secured at this stage. Submitting to the Building Division before completing these steps will result in an automatic rejection.
Submit Your Permit Application: Complete the City of St. Louis building permit application form and assemble your full package: the application, site plan, construction drawings, any pre-approval letters, and payment of the applicable permit fee. Submit online through the city's permitting portal or in person at 1200 Market Street, Room 425. Simple projects may qualify for same-day over-the-counter review, while formal plan review for larger projects typically takes 10 to 20 business days.
Schedule Inspections and Close the Permit: Once your permit is approved, post it on site as required and begin construction. Schedule all required inspections through the Building Division at the stages specified in your permit, typically including footing, framing, and final inspections. Do not cover work before it is inspected. After the final inspection passes, your permit is closed and the project is officially on record, protecting your investment and ensuring clear title when you sell the property.