For homeowners in Union, Missouri and nearby communities like Washington, Festus, and St. Clair, replacing or installing a roof isn’t just about choosing the right shingles or hiring a trusted contractor. One of the most important — and often overlooked — parts of the process involves understanding roofing building codes.
These codes are more than technical requirements. They’re safeguards that ensure your roof can handle Missouri’s seasonal extremes — from summer storms to winter snow. In this guide, Emmendorfer Exteriors breaks down what roofing building codes are, why they matter, and how they impact your roofing project in Union and surrounding towns.
What Are Roofing Building Codes?
Roofing building codes are a set of legal standards that regulate how roofing systems should be built, repaired, or replaced. These codes are adopted at the local level, often based on the International Residential Code (IRC), and modified to meet local conditions and safety priorities.
In towns like Union, Eureka, and Gerald, these codes may dictate:
- The number of allowable roof layers
- Types of underlayment and flashing
- How materials are installed and fastened
- Required ventilation systems
- Ice barrier provisions
- Roof pitch and slope for drainage
Following these rules isn’t optional — it’s mandatory. Skipping or ignoring roofing building codes can lead to failed inspections, fines, delays, and expensive rework.
Why Roofing Building Codes Matter to Missouri Homeowners
Understanding and complying with roofing building codes is critical for every homeowner, whether you’re upgrading your existing roof or building new. Here’s why:
- Safety: Codes are designed to protect your home and family by ensuring roofs withstand wind, rain, hail, and snow loads.
- Insurance Compliance: Most insurance providers require proof that your roofing work followed local codes.
- Property Value: A code-compliant roof boosts your home’s value and makes it easier to pass inspections during a sale.
- Liability Protection: If you sell your home or someone is injured due to code violations, you could be legally responsible.
- Financial Protection: Following codes helps you avoid costly mistakes, repairs, or having to re-do unapproved work.
Homeowners in Pevely, Valley Park, or Herculaneum should always ask their contractor whether work will be done to meet or exceed current roofing building codes.
Permit Requirements in Union and Surrounding Cities
Most cities in Missouri require a permit before you can install or replace a roof. That includes:
- Union
- Washington
- Festus
- St. Clair
- DeSoto
- Gerald
- Eureka
- Valley Park
- Fenton
- Herculaneum
- Pevely
Permit fees vary, but most fall between $50 and $300. Your contractor should handle the permitting process and ensure the work passes final inspection. Any roofing job done without a permit risks being flagged by code enforcement, which can halt your project and lead to fines or removal.
Roofing Materials and Code Compliance
Building codes don’t just affect how roofs are built — they also govern what materials can be used.
In Union and neighboring towns, approved materials typically include:
- Asphalt shingles
- Architectural shingles
- Metal roofing
- Wood shakes (with fire-rated coatings)
- Synthetic slate or tile
Local codes may specify which brands or types meet wind and fire resistance requirements. For example, roofs in Eureka and Fenton may require materials rated for high wind uplift or class A fire resistance due to regional weather risks.
Before purchasing roofing materials, your contractor should verify they meet all local roofing building codes.
Tear-Off Rules and Layer Limits
Most towns in Missouri prohibit more than two layers of roofing material. That means if your home already has two layers of shingles, they must be removed before a new roof is installed.
Union and nearby municipalities may also require a full tear-off if:
- The roof deck is rotted, warped, or soft
- Moisture damage is detected
- Shingles are curled or lifting
- Ice dams have formed in previous winters
These tear-off rules are part of roofing building codes that prioritize long-term performance over quick fixes. Though removing old shingles adds to the project cost, it ensures the new roof lasts and performs properly.
Roof Decking and Structural Integrity
Underneath your shingles is the roof decking — typically plywood or OSB boards that form the structural base. If this decking is compromised by leaks or rot, it must be replaced to meet code.
Contractors in Washington, Valley Park, and Herculaneum are required to inspect the decking and replace any damaged panels. This step is critical not just for code compliance but for safety. A weakened deck can’t properly support the roofing system and may lead to sagging or collapse.
Underlayment and Ice Barriers
Roof underlayment — the protective barrier between shingles and decking — plays a huge role in code compliance. In Missouri, building codes often require:
- Synthetic or asphalt-felt underlayment across the full roof surface
- Ice and water shield along eaves, valleys, and low-slope areas
- Leak barriers around penetrations like vents and chimneys
These barriers are designed to prevent water intrusion, especially during heavy snow or ice storms common in towns like Festus and Pevely.
Failure to install underlayment or ice shields according to roofing building codes can lead to rejected inspections and major water damage later.
Roof Ventilation Standards
Roof ventilation is another area where codes come into play. Proper attic ventilation:
- Extends the life of your roof
- Prevents ice dams
- Reduces moisture buildup
- Improves energy efficiency
Most building codes in Missouri require a ratio of 1 square foot of ventilation for every 150 square feet of attic space. In some cases, that ratio changes to 1:300 if balanced intake and exhaust vents are used.
Homeowners in DeSoto, Fenton, and Eureka should work with contractors who understand ventilation code requirements — especially in areas with extreme seasonal changes.
Fastening and Installation Methods
How your shingles or metal panels are fastened is also dictated by roofing building codes. Common requirements include:
- Nails must penetrate the decking by at least ¾ inch
- Staples are no longer accepted in many municipalities
- Shingles must be installed according to manufacturer instructions and local wind zone standards
- Drip edge flashing must be installed at eaves and rakes
Improper fastening is one of the leading causes of premature roof failure — and failed code inspections. That’s why every homeowner from Union to St. Clair should choose licensed roofers who follow code-approved installation techniques.
Fire Resistance and Weather Ratings
Towns like Herculaneum, Gerald, and Eureka may require specific fire or wind ratings based on local risk factors. For example:
- Class A fire-rated shingles are typically required
- Wind-resistant materials are recommended in areas with frequent storms
- Certain neighborhoods may require hail-resistant roofing systems
Check with your city’s building department or ask your contractor to confirm whether your selected materials meet required roofing building codes.
Inspections and Final Approval
Once the roof installation is complete, a final inspection is usually required before the permit can be closed. Inspectors will check:
- Flashing installation
- Shingle alignment and fastening
- Proper ventilation
- Underlayment coverage
- Compliance with local pitch and slope standards
A passed inspection means your roof is legally complete and code-compliant. If issues are found, they must be corrected before you can move forward.
Homeowners in Union, Washington, or Eureka should always verify that their contractor has scheduled and passed the final inspection.
Choosing a Contractor Who Understands Roofing Building Codes
The best way to avoid problems with roofing building codes is to hire a professional who understands them inside and out. Emmendorfer Exteriors serves Union, MO and surrounding towns with experienced, licensed crews who follow all current codes for every project.
We handle:
- Permit applications
- Material selection based on local code
- Code-compliant tear-offs and installation
- Scheduling and passing inspections
We stay up to date with the changing requirements in all of the areas we serve, including Washington, Festus, Gerald, Fenton, DeSoto, and beyond.
Final Thoughts: Know the Codes Before You Roof
Understanding and following roofing building codes isn’t just about passing inspections — it’s about protecting your home and avoiding future headaches.
If you live in Union, Washington, Festus, or any of the surrounding Missouri towns, make sure your roofing project is built on a solid foundation — legally and structurally. Work with contractors who prioritize compliance, who communicate clearly, and who respect your home as much as you do.
