In the logistics of steel structures, there is a critical threshold: 24 feet wide. Below 24 feet (standard 1-Car and 2-Car Carports), the engineering is straightforward. The trusses are simple bows. But once you cross into 26-foot to 30-foot widths—the territory of the 3-Car Carport or “Triple Wide”—the physics change completely.
As the Supply Chain Director, I authorize the release of these structures daily. I also see the warranty claims from customers who bought a non-certified Triple Wide from a budget competitor and watched it buckle under 6 inches of wet snow.
A 3-Car Carport acts as a massive sail in the wind and a giant catchment basin for snow. You cannot simply “scale up” a small carport design. You need a different structural system entirely. This guide is your “Engineering 101” for Triple Wide planning. We will move past the aesthetics and look at the raw numbers: Truss strength, Anchor pull-out ratings, and Wind Load limits.
1. The “Triple Wide” Definition: Understanding the Scale
First, let’s define what we are building. In our inventory system, a “Triple Wide” is any clear-span structure between 26 feet and 30 feet wide. Unlike commercial clear-span buildings (which use massive I-beams), Triple Wides use a reinforced tubular steel truss system to keep costs reasonable for residential use.
Table 1: Triple Wide Dimensions & Capacity Logistics
| Breite | Typical Use Case | Vehicle Capacity | Recommended Minimum Length |
|---|---|---|---|
| 26 Feet | 3 Compact Cars OR 2 Full-Size Trucks + ATV | Tight fit for 3 daily drivers. | 21 Feet (Bare Minimum) |
| 28 Feet | 3 SUVs / Sedans | Comfortable fit; doors can open freely. | 26 Feet (Standard) |
| 30 Feet | 3 Full-Size Trucks OR 2 Cars + Boat | Maximum residential width. | 31 Feet or 36 Feet |
Director’s Note: Never buy a 26-foot wide carport for three full-size American pickup trucks (e.g., F-150s). You will not be able to open the doors. For three trucks, you need the full 30-foot width.
2. The Truss System: The Backbone of the Beast
This is where the supply chain quality matters most. On a standard 18-foot carport, the roof bow is a simple bent tube. On a 30-foot Dreifach breiter Carport, a simple tube would sag under its own weight.
We use a Webbed Truss design for all Triple Wides. This means every roof bow is actually two steel tubes welded together with a zig-zag webbing pattern in between. This creates a bridge-like structure capable of spanning the distance without interior columns.
Table 2: Truss Engineering Specifications
| Feature | Standard Carport (12′-24′) | Triple Wide Carport (26′-30′) | Why It Matters? |
|---|---|---|---|
| Truss Design | Single Tube Bow | Welded Web Truss | Prevents roof sagging in the middle. |
| Corner Bracing | 2-3 Foot Braces | 4-Foot or Full Web Bracing | Prevents the structure from “racking” (leaning) in wind. |
| Leg Spacing | Up to 5 Feet | 4 Feet Maximum | Tighter leg spacing supports the heavier roof weight. |
| Steel Gauge | 14-Gauge Standard | 14-Gauge (Standard) or 12-Gauge (Heavy) | We highly recommend upgrading to 12-Gauge for 30′ spans. |
3. Wind Load Dynamics: Managing the “Sail Effect”
Imagine holding a 30-foot wide sheet of plywood in a windstorm. That is essentially what your carport roof is. Wind load isn’t just about the wind blowing against the side; the bigger danger for Triple Wides is Uplift. Wind gets under the large canopy and tries to lift the entire structure out of the ground like a kite.
To combat this, our Certified Triple Wide units are engineered to withstand winds up to 140 mph (and higher in coastal zones).
Table 3: Wind Rating vs. Structural Requirements
| Wind Speed Rating | Structural Requirement | Anchoring Requirement | Supply Chain Rec |
|---|---|---|---|
| 100 mph (Non-Certified) | Standard spacing (5′ on center). | Standard Rebar Anchors. | NOT RECOMMENDED for Triple Wides. Too risky. |
| 130 mph (Certified) | Tighter spacing (4′ on center). | Mobile Home Augers (Earth) or Wedges (Concrete). | The Minimum Standard for most US states. |
| 150+ mph (High Wind) | 12-Gauge Steel + Extra Bracing. | Cemented Anchors + High-Wind pattern. | Mandatory for FL and Coastal TX/SC. |
Director’s Warning: If you live in an open area (farm, field) where wind accelerates without obstruction, do not buy a non-certified 3-Car Carport. The cost difference is minimal compared to the cost of your carport flying into your neighbor’s living room.
4. Snow Load Logistics: The Weight of Winter
Snow is heavy. Wet snow can weigh 20 pounds per square foot (PSF). On a 30′ x 40′ Triple Wide Carport, that is 1,200 square feet of roof. If you get 1 foot of wet snow (20 PSF), your carport is holding 24,000 POUNDS of weight. That is the equivalent of parking four Ford F-250s on the roof.
This is why roof style is critical.
Table 4: Roof Style Performance for 3-Car Units
| Dachform | Beschreibung | Suitability for Triple Wide | Snow Load Risk |
|---|---|---|---|
| Regular (Rounded) | Horizontal Panels. | POOR. | High. Snow sticks to the ridges. Structure may bow. |
| Boxed-Eave (A-Frame) | Horizontal Panels. | FAIR. | Moderate. Better look, but snow still doesn’t slide off easily. |
| Vertikales Dach | Vertical Panels. | EXCELLENT. | Low. Snow slides off immediately. Hat-channel purlins add strength. |
The Supply Chain Rule: We strongly discourage selling Regular or Boxed-Eave styles on 30-foot wide units in snow zones. The risk of collapse is too high. Always upgrade to the Vertikales Dach for a 3-Car Carport. The vertical orientation adds structural cross-bracing (purlins) that horizontal roofs lack.
5. Anchoring 101: Keeping It Grounded
You have the heavy truss, you have the vertical roof. Now, how do we keep it on the ground? Anchoring a Triple Wide is not a DIY job with a tent stake. The sheer surface area requires industrial holding power.
Table 5: Anchor Types and Pull-Out Strength
| Anchor Type | Surface Application | Pull-Out Resistance (Approx) | Notes |
|---|---|---|---|
| Rebar Pin (30″) | Dirt / Asphalt | ~400 lbs | Temporary only. Never rely on this for a 3-Car unit. |
| Mobile Home Auger (30″) | Dirt / Gravel | ~2,500 – 3,500 lbs | Standard for Certified ground installs. Screws deep into earth. |
| Asphalt Anchor | Asphalt Driveway | ~1,500 lbs | Specialized barb design. |
| Wedge Anchor (5/8″ x 6″) | Betonplatte | ~5,000+ lbs | The Gold Standard. Expands inside the concrete. |
Logistics Tip: If you are installing on dirt, we typically install auger anchors every 8 to 10 feet. On a high-wind certified unit, we may install them on every leg.
6. Foundation Requirements: The Concrete Slab
While you can install a Triple Wide on dirt or gravel, most customers investing in a 3-car structure choose to pour a concrete slab. Because the legs of a 30-foot truss exert significant downward pressure (point load), the slab edges must be reinforced.
Table 6: Concrete Slab Specifications for Triple Wides
| Spec | Recommendation | Why? |
|---|---|---|
| Slab Thickness | 4 Inches (Minimum) | Standard vehicle weight support. |
| PSI Rating | 3000 – 4000 PSI | Prevents cracking under heavy trucks. |
| Edge Footing (Turndown) | 12″ Deep x 12″ Wide | Critical. The perimeter carries the weight of the building. |
| Width Sizing | Exact Width or +2 Inches | Do not pour the slab exactly 30′ wide if the frame is 30′ wide; give yourself a 2″ margin for error. |
| Length Sizing | Length + 1 Foot | E.g., for a 31′ carport, pour a 32′ slab. |
Common Mistake: Customers pour a slab exactly 30′ x 30′ for a 30′ x 30′ building. If the concrete form bowed slightly during pouring, one leg might hang off the edge. Always pour the slab 1 foot wider and longer than the frame.
7. The Cost Efficiency of Triple Wides
From a supply chain perspective, buying one Dreifach breiter Carport is significantly cheaper than buying a 2-Auto Carport plus a separate 1-Car Carport. You save on logistics (one delivery truck), installation labor (one crew trip), and materials (sharing the center support structure).
Table 7: Cost Efficiency Analysis (Estimated)
| Option | Approximate Cost | Profis | Cons |
|---|---|---|---|
| (1) 30′ x 26′ Triple Wide | $4,500 – $6,000 | Cheapest per sq. ft.; Open floor plan. | Needs a massive clear space. |
| (1) 20′ x 26′ + (1) 12′ x 26′ | $6,500 – $8,500 | Can separate vehicles (e.g., boat vs. car). | Higher cost; Wasted space between units. |
| (1) 20′ x 26′ with Lean-To | $5,000 – $6,500 | Good for zoning restrictions. | Lean-to side has lower height. |
8. Permitting and Inspection: The Paper Trail
Because Triple Wides are substantial structures (often exceeding 800 sq. ft.), they almost always trigger local building permits. When you order a 3-Car Carport from us, you need to request the Generic Engineering Plans (Blueprints).
- Wind Load Calculation: Your permit office will want to see that the engineer has calculated the uplift on a 30-foot span.
- Snow Load Calculation: In the north, they need to verify the truss can handle the specific ground snow load (e.g., 40 PSF).
- Truss Details: The inspector will check the weld spacing on the web trusses.
Supply Chain Director’s Advice: Do not try to fly under the radar with a Triple Wide. It is too big to hide behind a fence. Get the permit. We provide the engineering drawings to back you up.
Conclusion: Build It Wide, Build It Strong
A 3-Car Carport is a fantastic investment. It covers your daily drivers and your weekend toys in one cohesive structure. It adds significant appraisal value to your property.
But please, respect the physics.
- Don’t skimp on the width (go for 28′ or 30′ if you have trucks).
- Don’t skip the Vertical Roof (especially if you ever see snow).
- Don’t ignore the foundation (reinforce those slab edges).
We have the trusses in stock, welded and ready to ship. We have the logistics network to deliver 30-foot spans directly to your job site. When you are ready to build big, build it right.
Frequently Asked Questions (FAQ)
Q: Can I install a garage door on a Triple Wide later? A: Yes, but you need to plan for leg height. If you want to install standard 8-foot tall garage doors later, you should order the carport with at least 9-foot or 10-foot legs now. You need room for the door tracks and the roll-up header.
Q: Does a Triple Wide require a center post? A: No! That is the beauty of the Webbed Truss. It is a “Clear Span” structure. You have 30 feet of open space with no annoying poles to hit with your car door.
Q: What is the maximum height for a Triple Wide? A: We can engineer them up to 16 feet tall (side leg height). This is popular for Wohnmobil-Carports or combining an RV spot with two car spots. However, once you go above 12 feet, we strongly
