As a Supply Chain Director in the metal building industry, my job involves more than just sourcing high-quality steel and managing logistics. It is about risk management and ensuring that the structures we deliver—whether they are One-Car Garages or massive 6-Car Garages—meet the highest safety standards.
When you scale up to a 6-car facility, you are no longer dealing with a simple residential parking spot. You are effectively managing a small warehouse that houses thousands of gallons of fuel, oils, and combustible materials within the vehicles themselves. Because of this, fire separation isn’t just a “good idea”; it is often a legal requirement mandated by the International Building Code (IBC) and local zoning laws.
In this guide, we will break down the technical requirements for fire-rated walls, doors, and assemblies specifically for Custom Garages of this scale. If you are looking to purchase a Metal Carport Kit or a Build-It-Yourself Garage Kit, understanding these safety protocols is essential for your permit approval and your peace of mind.
1. Why Fire Separation is Critical for 6-Car Structures
A 6-Car Garage typically spans between 1,200 and 2,000 square feet. From a fire safety perspective, this large volume of space creates a significant “fuel load.” If a fire starts in one vehicle, the proximity of five other vehicles can lead to a rapid, catastrophic chain reaction.
The Residential vs. Commercial Overlap
Most residential codes (like the IRC) require fire separation if the garage is attached to a dwelling. However, for a detached 6-Car Garage, the rules change based on its proximity to other buildings. As a supplier, we often see wholesale clients who need “One-Hour Fire Ratings” to satisfy commercial insurance requirements, even if the building is technically for private use.
| Feature | Standard Garage (1-2 Car) | Large Scale Garage (6-Car) |
|---|---|---|
| Typical Square Footage | 400 – 600 sq. ft. | 1,200 – 2,000+ sq. ft. |
| Combustible Load | Low (1-2 fuel tanks) | High (6 fuel tanks + storage) |
| Separation Requirement | Usually 1/2″ Drywall | Often 5/8″ Type X or Multiple Layers |
| Structural Demand | Standard 14-Gauge | Heavy Duty 12-Gauge Steel |
2. Fire-Rated Wall Assemblies: The “One-Hour” Rule
In the world of metal buildings, steel is non-combustible. It won’t catch fire. However, at high temperatures (around 1,100°F), steel loses its structural integrity and can buckle. This is why we use “Rated Assemblies” to protect the steel frame.
What is a “One-Hour” Rating?
A one-hour fire rating means the wall assembly can withstand a standardized fire test for at least 60 minutes before failing. For a 6-Car Garage, this is often required on the wall that faces the primary residence or the property line.
Components of a Rated Assembly:
- Type X Drywall: This is 5/8-inch thick gypsum board reinforced with glass fibers. These fibers hold the gypsum together even when the moisture inside the board evaporates during a fire.
- Fire-Rated Sealants: Any gaps where the wall meets the roof or floor must be sealed with intumescent caulk.
- Steel Studs: In our Custom Garages, the heavy-duty 12-gauge steel frames serve as the skeleton for these assemblies.
Table: Common Fire-Rated Wall Materials
| Material | Fire Rating | Pros | Cons |
|---|---|---|---|
| 1/2″ Regular Gypsum | ~20-30 Minutes | Cheap, Lightweight | Not code-compliant for 6-car separation. |
| 5/8″ Type X Gypsum | 60 Minutes (One Layer) | Industry Standard | Requires careful installation. |
| Double 5/8″ Type X | 120 Minutes | Maximum Protection | Expensive and Heavy. |
| Mineral Wool Insulation | Non-Combustible | Added thermal and fire protection | Higher material cost. |
3. Fire-Rated Doors: The Critical Breach Point
A wall is only as strong as its weakest point. In a 6-Car Garage, the doors leading into a workshop or an attached home must be specifically rated. From a supply chain perspective, sourcing these doors is a specialized process, as they must carry a UL (Underwriters Laboratories) label.
Requirements for Garage-to-House Doors:
- Self-Closing: The door must have a spring hinge or a door closer to ensure it never stays open accidentally.
- Self-Latching: The door must latch automatically when closed.
- Materials: Must be either a solid-core wood door (at least 1-3/8 inches thick), a honeycomb-core steel door, or a 20-minute fire-rated door.
The “Threshold” Factor
In large Metal Garages, we often recommend a raised threshold. This prevents spilled gasoline or vapors from flowing from the garage floor under the door and into adjacent spaces.
4. Ceilings and “Plenum” Spaces in Large Garages
When you have a 6-Car Garage with a high ceiling—perhaps to accommodate an RV Carport section or a Boat Garage—the attic space becomes a safety concern. Fire can travel through the “plenum” (the space between the ceiling and the roof) and bypass your wall protections.
Fireblocking in the Ceiling
If you are finishing the interior of your Build-It-Yourself Garage Kit, you must install fireblocks. These are pieces of non-combustible material (like scrap steel or fire-rated lumber) that block the hidden paths that flames and smoke use to travel.
Table: Ceiling Protection Standards
| Method | Rating | Best Use Case |
|---|---|---|
| Open Steel Trusses | Non-Combustible | Standard Detached Custom Garages. |
| Sheetrock Ceiling | 1-Hour | Garages with living space above (lofts). |
| Fire-Rated Drop Ceiling | Variable | Commercial workshops and showrooms. |
5. Integrating Specialized Vehicle Storage (RVs and Boats)
A 6-Car Garage often houses more than just cars. You might have an RV Garage bay or a Boat Garage section. These vehicles bring unique fire risks.
- RV Garages: RVs often have propane tanks for cooking and heating. Propane is heavier than air and can pool on the floor, creating an explosion risk. Fire separation walls must be sealed at the floor level with extra care in these bays.
- Boat Garages: Fiberglass boats burn very hot and produce toxic smoke. If your 6-car facility is a hybrid Boat Carport and enclosed garage, ensure the enclosed section has independent ventilation.
6. Sourcing Fire-Safe Kits: The Supply Chain Advantage
When you order a Metal Carport Kit or a Triple Wide Carport from a reputable supplier, you are getting more than just metal. You are getting a system designed for compliance.
Wholesale and Custom Ordering
For our wholesale clients—such as car dealerships or storage facility developers—we provide “Engineering Packets.” These include the fire-rating data for our steel gauges and recommended assembly details.
Why choose a kit?
- Consistency: Every piece of the 2-Car Garage or 4-Car Garage is precision-cut to fit the rated assembly.
- Speed: Build-It-Yourself Garage Kits come with instructions on how to maintain fire gaps and where to apply fire-rated sealants.
- Certification: Our buildings can be certified for specific wind, snow, and fire loads, which is often required for commercial insurance.
7. Foundations and Anchoring: The Hidden Role in Safety
While we focus on walls and doors, the foundation plays a role in fire safety. In a fire, if a building’s anchors fail, the structure collapses, making it impossible for firefighters to enter.
Anchoring Your Garage
We offer several anchoring methods:
- Concrete Anchors: Standard for Custom Garages on slabs. These are the most fire-resistant.
- Mobile Home Anchors: Used for Metal Carports on dirt or gravel. While strong, they are less stable in a high-heat collapse scenario than concrete-embedded anchors.
8. Frequently Asked Questions (FAQ)
Does a detached 6-car garage need a 1-hour fire wall?
It depends on the “separation distance.” Usually, if the garage is more than 10 feet from any other building, a fire-rated wall is not required by code, though it is still recommended for high-value collections.
Can I use a regular metal door for my garage?
For exterior doors, yes. For a door that connects the garage to a home or an office, it must be a fire-rated assembly with a self-closer.
How do I insulate a fire-rated wall?
We recommend mineral wool (like Rockwool). Unlike fiberglass, mineral wool has a much higher melting point and does not contribute to the spread of flames.
9. Conclusion: Trusting the Professional Supply Path
As a Supply Chain Director, my priority is the longevity and safety of the structures we put into the market. A 6-Car Garage is a significant investment, often protecting hundreds of thousands of dollars in vehicles. Cutting corners on fire separation is not just a code violation—it is a risk to your assets and your life.
Whether you are looking for a One-Car Garage for your daily driver or a massive Custom Garage for a fleet, we provide the technical expertise and the high-quality materials needed to build safely. Our Metal Carport Kits and Build-It-Yourself Garage Kits are designed with these standards in mind, making it easier for you to navigate the complexities of modern building codes.
Ready to start your 6-car project? Contact our team today for a consultation. We can provide the technical specs you need for fire-rated assemblies and help you customize the perfect facility for your collection.
6-Car Garage Fire Safety Checklist:
- [ ] Verify the “Separation Distance” from your home.
- [ ] Settle on 5/8″ Type X drywall for shared walls.
- [ ] Source a UL-labeled, self-closing door for interior access.
- [ ] Install fire-rated caulk at all joints and penetrations.
- [ ] Consider mineral wool insulation for added safety.
- [ ] Ensure your Custom Garage is certified by a professional engineer.
By following these professional standards, you aren’t just building a garage; you are building a secure facility that will protect your vehicles for decades to come.
