Metal Building Framing Options: Tubular Steel, Trusses & Red Iron Frames
When designing a metal building, the frame is one of the most important parts of the entire structure. It affects the building’s strength, width, height, roof support, door placement, certification requirements, and long-term usability.
At Legacy Carports, we help customers compare framing options before their order is sent to the appropriate manufacturing plant. The right frame depends on how the structure will be used, where it will be installed, local wind and snow load requirements, and whether the project is better suited for tubular steel or red iron framing.
Quick Answer: What Framing Option Do You Need?
The right metal building frame depends on the structure’s width, height, location, wind load, snow load, and how the building will be used. Many tubular steel structures 24 feet wide or less use standard framing. Structures around 26 to 30 feet wide may require a welded truss, while structures around 32 feet wide or larger commonly use a commercial truss.
Tubular steel framing is a strong fit for many carports, garages, RV covers, workshops, and storage structures. For larger buildings, especially around 50 feet wide or more, it may be worth comparing tubular steel with red iron framing. Red iron buildings are engineered to the project’s specific dimensions and are often better suited for larger commercial, agricultural, or wide-span structures.
Framing requirements can vary by location, manufacturer, certification, building height, enclosure, and local code requirements, so every project should be reviewed before finalizing the design.
What Is the Frame of a Metal Building?
The frame is the structural skeleton of a metal building. It supports the roof, walls, panels, doors, windows, trim, and other building components.
On many tubular steel structures, the frame includes the legs, base rails, roof bows, braces, and other steel members that work together to support the building.
For larger steel buildings, framing may include heavier structural components, clear-span frames, columns, rafters, purlins, girts, and other engineered steel parts. These designs are often used for wide buildings, commercial structures, agricultural buildings, warehouses, and projects that require larger open spaces.
While customers often focus first on colors, doors, windows, or roof style, the framing is what determines much of the building’s strength and function.
Why Metal Building Framing Matters
Your framing choices can affect more than just the strength of the structure. Framing can also influence the building’s height, width, interior clearance, door placement, certification requirements, and final price.
A stronger or more advanced frame may be needed when the building is taller, wider, fully enclosed, certified for wind and snow, or designed for a specific use such as equipment storage, RV parking, commercial access, or workshop space.
Good framing planning helps determine whether the structure can support the size you want, provide enough clearance for vehicles or equipment, allow for large garage doors or frame-outs, meet local wind and snow load requirements, and keep the interior as open as possible.
These are the types of details that should be reviewed before placing an order, not after.
What Legacy Carports Looks at Before Recommending a Frame
Before recommending a frame, Legacy Carports looks at more than just the building size. We consider the structure’s width, length, leg height, roof style, enclosure, door openings, installation surface, wind load, snow load, and whether the project may require permits or engineering.
A small open carport may not need the same framing as a fully enclosed garage with large doors. A tall RV cover may need different support than a low-profile storage building. A wide commercial structure may need a truss system or may be better suited for red iron framing.
Reviewing these details early helps customers avoid choosing a structure that looks right online but does not fit their actual use, site, or local requirements.
Tubular Steel Framing
Tubular steel framing is commonly used for metal carports, garages, RV covers, barns, and many residential or light commercial structures. These buildings are popular because they are durable, cost-effective, and highly customizable.
Tubular steel structures are often built using galvanized steel tubing. The frame is designed to support the roof system, side panels, end walls, doors, windows, and other selected options. Depending on the size and location of the structure, different framing upgrades may be available or required.
Tubular steel framing is a great fit for many common projects, including carports, metal garages, RV covers, storage buildings, workshops, equipment covers, agricultural covers, and small business storage structures.
For many customers, tubular steel framing offers the right balance of strength, affordability, and customization.
Common Tubular Steel Building Frame Options by Width
Tubular steel framing can vary depending on the width, height, location, and certification requirements of the structure. While every project should be reviewed based on its final design, many tubular steel buildings follow a general framing progression as they get wider.
For many standard structures, widths of 24 feet or less commonly use standard tubular steel framing. Once a structure reaches around 26 to 30 feet wide, a welded truss may be required to provide additional support. For structures around 32 feet wide or larger, a commercial truss is commonly used to help support the wider span.
These framing changes are important because a wider building needs more support across the roof system. The frame has to be designed to handle the building’s size, selected options, and local wind or snow load requirements.
This is also why two buildings that look similar online may have different pricing once the width, height, certification, and framing requirements are reviewed.
Standard Tubular Steel Framing
Standard tubular steel framing is commonly used on many smaller and mid-sized structures. This type of frame is often suitable for carports, garages, storage buildings, workshops, and RV covers that fall within standard size and engineering requirements.
For many structures 24 feet wide or less, standard framing is commonly used, depending on the location, building height, roof style, enclosure, and certification needs.
Welded Truss Framing
A welded truss may be required when a tubular steel structure gets wider and needs additional support across the roof span.
This is commonly seen on structures around 26 to 30 feet wide, depending on the building design and local requirements. The truss helps strengthen the roof system and allows the structure to handle a wider span than a smaller standard frame.
Commercial Truss Framing
Commercial truss framing is commonly used for larger tubular steel structures where additional strength is needed.
For structures around 32 feet wide or larger, a commercial truss may be used to support the wider frame. These structures are often larger, taller, more heavily enclosed, or built for more demanding residential, agricultural, or commercial use.
The exact frame needed depends on the building size, wind load, snow load, certification requirements, and manufacturer specifications.
General Tubular Steel Framing Guide
Building Width | Common Frame Type | What it means |
|---|---|---|
24' wide or less | Standard framing | Common for many standard carports, garages, RV covers, and storage buildings |
26'–30' wide | Welded truss | Adds support for wider tubular steel spans |
32'+ wide | Commercial truss | Common for larger tubular steel buildings needing more roof support |
Around 50'+ wide | Compare tubular steel and red iron | Red iron may be worth considering depending on the area, use, and requirements |
These are general guidelines, not universal engineering rules. Final framing requirements can vary by manufacturer, location, wind load, snow load, building height, enclosure, door openings, and local code requirements.
Metal Building Frame Spacing: 5' On Center vs. 4' On Center
Tubular steel framing is commonly spaced around 5 feet on center, meaning the main frame sections are typically placed about 5 feet apart. This is a common spacing used on many tubular steel carports, garages, and metal buildings.
In some states, regions, or project designs, the frame spacing may be upgraded to 4 feet on center. This tighter spacing adds more frame sections to the structure and can provide additional support depending on wind load, snow load, certification requirements, building size, or local code expectations.
Additional bows may also be added in certain situations to decrease the spacing even more when the structure or location requires it.
For contractors, 4-foot on-center spacing can also be helpful when finishing the inside of a metal building. Since many traditional construction materials are based around 4-foot dimensions, tighter spacing may make it more convenient to add drywall, liner panels, insulation, or other interior finishes.
Like other framing upgrades, the right spacing depends on the building design, installation area, and how the structure will be used.
Tubular Steel Frame Strength Upgrades
Some tubular steel structures may require additional framing support depending on the width, height, wind load, snow load, certification requirements, or overall design. Common strength upgrades can include double legs and laddered legs.
These upgrades are usually used when the structure needs more support than a standard leg system provides. In some cases, customers may also choose a stronger leg system even when it is not strictly required.
The important thing to understand is that both double legs and laddered legs typically include an additional base rail. The second leg needs another base rail to sit on, whether that second leg is welded beside the main leg or built into a laddered-leg design.
The best option depends on the project. A simple carport may not need the same framing upgrades as a tall RV cover, enclosed garage, commercial storage structure, or building in a high wind or snow load area.
Double Legs
Double legs add a second vertical steel member beside the main leg to increase frame support. This can help strengthen the structure, especially on taller buildings, wider buildings, or structures with higher wind or snow load requirements.
Because the second leg needs a support point at the ground level, double-leg systems typically include a second base rail.
Laddered Legs
Laddered legs use additional steel members to create a stronger leg design. This upgrade may be used when the building needs extra support due to height, width, certification requirements, or overall structure design.
Like double legs, laddered legs typically include a second base rail because the added leg section needs its own support point at the bottom of the frame.
12-Gauge vs. 14-Gauge Framing
One of the most common questions customers ask is about steel gauge. In simple terms, gauge refers to the thickness of the steel used in the frame.
Many metal buildings are available with standard 14-gauge framing. This is a common option for many carports, garages, and storage buildings. In some areas or for certain structures, customers may also have the option to upgrade to 12-gauge framing.
A 12-gauge frame is thicker than a 14-gauge frame. This can provide additional strength and may be recommended or required depending on the building size, local code requirements, certification needs, or the customer’s intended use.
The best choice depends on the structure, location, and manufacturer availability. Not every option is available for every building or every installation area, which is why it is important to review the details before finalizing your order.
Leg Height and Clearance
Leg height is another important framing decision. The leg height helps determine the side clearance of the building and affects how much usable height you have inside the structure.
This is especially important if you are storing taller vehicles or equipment, such as RVs, campers, boats, lifted trucks, tractors, trailers, commercial vehicles, or farm equipment.
A common mistake is choosing a structure that looks tall enough in a picture but does not provide enough usable clearance once the roof system, trim, garage doors, or frame components are considered.
For enclosed garages, customers should also think about garage door height. The overall leg height needs to work with the size of the garage door, the roof style, and the structure’s intended use.
Bracing and Structural Support
Bracing helps strengthen the frame and improve the stability of the structure. Bracing may be used in the corners, roof system, sidewalls, or other areas depending on the design.
On certified structures, bracing can be especially important because the building may need to meet specific wind or snow load requirements. Bracing can also affect where certain doors, windows, or frame-outs can be placed.
This is one reason large openings should be planned carefully. If you want a big garage door, wide side opening, lean-to, or custom frame-out, the framing may need to be reviewed to make sure the design still meets structural requirements.
Framing for Garage Doors, Windows, and Walk-In Doors
The frame of your metal building also affects where doors and windows can be placed. Garage doors, walk-in doors, and windows all require proper framing around the opening.
Larger garage doors or wide frame-outs may require additional engineering or special design consideration. This is especially true when openings are placed on sidewalls or when multiple large openings are being added to the same wall.
Before choosing your final layout, it is important to think about how you will use the building every day. A good framing layout can make the structure easier to access, easier to organize, and better suited for your long-term plans.
Framing for Lean-Tos
Lean-tos are a popular option for customers who want extra covered space on the side of a building. They can be used for parking, outdoor storage, shade, equipment coverage, or additional workspace.
However, lean-tos should be planned early because they connect to the main structure and can affect the building’s frame design. Adding a lean-to later is not always simple, especially if the original structure was not designed for it.
Depending on the size, location, and layout, a lean-to may require specific connection points, additional bracing, or engineering review. If you are considering a lean-to, it is best to include it during the original design process.
Framing for Certified Metal Buildings
Certified metal buildings are designed to meet certain wind and snow load requirements. When a structure needs to be certified, the framing becomes even more important.
Certification may affect the frame gauge, anchor type, bracing, building width, building height, roof style, engineering requirements, foundation requirements, and door or window placement.
Certified structures are often required for permits or recommended in areas with heavier wind, snow, or local code requirements. If your county or city requires a building permit, they may also require engineered drawings or proof that the structure meets certain ratings.
When It May Make Sense to Move Into Red Iron Framing
Tubular steel is a great fit for many carports, garages, RV covers, workshops, and smaller storage buildings. However, once a structure becomes larger, wider, taller, or more complex, red iron framing may become the better option.
As a general guideline, once a building gets larger than roughly 50 feet wide, depending on the area and project requirements, it may be worth comparing tubular steel against red iron. In some cases, this transition point can vary between the 40 to 60 foot range, depending on the building design, local requirements, and how the structure will be used.
Red iron framing is often a better fit for projects that need large open spans, commercial use, higher sidewalls, heavy-duty framing, large equipment access, warehouse space, business storage, or more complex building layouts.
The goal is not always to choose the cheapest framing option. The goal is to choose the structure type that makes the most sense for the size, use, and long-term purpose of the building.
Red Iron Metal Building Framing
Red iron framing is commonly used for larger, heavier, or more complex steel building projects. Unlike many standard tubular steel structures, red iron buildings are typically engineered around the specific details of the project.
This means the frame is designed based on the building’s width, length, height, openings, loads, layout, and intended use. Because the frame is engineered to the individual specs of the building, major changes can be more difficult once the design is finalized.
Most red iron buildings use I-beam framing, which provides strong structural support for larger buildings. Some smaller buildings may use C-channel framing, depending on the design and engineering requirements.
In red iron construction, the vertical supports are often referred to as columns rather than legs. Depending on the project, customers may have options such as tapered columns or straight I-beam columns.
Because red iron buildings are more engineering-driven, it is especially important to plan the size, openings, frame style, and layout carefully before moving forward.
I-Beam Framing
I-beam framing is commonly used in red iron buildings because it provides strong structural support for larger spans, taller buildings, and heavier-duty applications.
This type of framing is often used for commercial buildings, warehouses, large shops, agricultural buildings, and other structures that need more strength or engineering than a standard tubular steel frame.
C-Channel Framing
Some smaller red iron or structural steel buildings may use C-channel framing, depending on the size, layout, and engineering requirements of the project.
C-channel framing is not used for every red iron building, but it may be an option for certain smaller structures where the design does not require the same type of heavy I-beam frame.
Tapered Columns vs. Straight I-Beam Columns
In red iron construction, the vertical supports are usually called columns. Depending on the project, customers may have options such as tapered columns or straight I-beam columns.
Tapered columns are wider at certain points and are often used to efficiently support the engineered frame. Straight I-beam columns provide a more uniform column shape and may be preferred in certain layouts or applications.
The right column style depends on the building design, engineering requirements, interior layout, and how the structure will be used.
Tubular Steel vs. Red Iron Framing
Tubular steel and red iron framing can both be good options, but they are usually used for different types of projects.
Framing Type | Best For | Common Uses |
|---|---|---|
Tubular Steel | Residential and light commercial structures | Carports, garages, RV covers, workshops, storage buildings |
Red Iron | Larger, wider, or more heavily engineered buildings | Carports, garages, RV covers, workshops, storage buildings |
Tubular steel is often more cost-effective for standard projects, while red iron may be better for large spans, heavier engineering requirements, or more complex layouts.
At Legacy Carports, we help customers understand which type of structure makes the most sense based on their project, location, and budget.
How Framing Can Affect Price
Framing is one of the biggest factors that can affect the final price of a metal building. A larger, taller, wider, or more heavily engineered frame will usually cost more than a smaller standard structure.
Framing-related price factors may include building width, building length, leg height, roof style, steel gauge, certified versus non-certified design, frame spacing, truss type, large door openings, lean-tos, custom frame-outs, engineering requirements, and foundation requirements.
This does not mean every customer needs the strongest or most expensive frame available. It means the frame should match the purpose of the structure.
A basic carport for everyday vehicle coverage does not always need the same framing approach as a wide commercial workshop, certified RV garage, or large red iron building.
How to Choose the Right Metal Building Frame
The best framing option depends on what you are building and how you plan to use it. Before choosing your frame, think about your long-term goals for the structure.
Consider what you plan to store, whether you need room for future vehicles or equipment, whether large garage doors are needed, and how much open interior space you want. It is also important to think about whether the structure is for residential, farm, or commercial use, and whether your county may require permits, engineering, or wind and snow load certification.
You should also consider any future options you may want to include, such as lean-tos, windows, walk-in doors, garage doors, enclosed sides, or interior finishing.
The more you know before ordering, the easier it is to design a structure that fits your property and avoids problems later.
Why Planning Your Frame Early Matters
Many building options connect back to the frame. Roof style, door placement, windows, lean-tos, panel orientation, certification, anchoring, and foundation requirements can all be affected by the structure’s framing.
That is why it is important to plan the frame before finalizing the design. Making major changes after the order is sent to manufacturing may not always be possible and can sometimes require new pricing, updated drawings, or additional approval.
This is especially true with red iron buildings because the frame is engineered to the individual specs of the project. Once the frame has been designed, changes to width, height, openings, or layout can be more difficult than they would be earlier in the planning process.
A well-planned frame helps create a smoother process from design to manufacturing to installation.
Get Help Choosing the Right Frame
Choosing the right frame does not have to be complicated. The key is understanding how the structure will be used, where it will be installed, and what options need to be included from the beginning.
Legacy Carports can help you compare framing options, review your design, and determine which structure type makes the most sense for your project. Whether you need a simple carport, enclosed garage, RV cover, workshop, or larger metal building, the right framing choice can make a big difference in how your structure performs over time.
Ready to start planning your structure? Use our 3D Builder or reach out to Legacy Carports for help designing a metal building that fits your needs.
