Red Iron Buildings vs. Tubular Steel Buildings: Which Do You Actually Need?

Shop for a steel building long enough and you will run into two terms that sound similar and are not: red iron buildings and tubular steel buildings. Both are “metal buildings.” Both use steel frames and steel panels. But they are engineered, delivered, founded and priced very differently, and choosing the wrong type means either overpaying for strength you will never use or buying a building that cannot do the job. We install tubular steel buildings and do not sell red iron, so this guide is also an honest account of when you should look elsewhere.

What is a red iron building?

A red iron building is framed with heavy structural steel: solid I-beam columns and rafters bolted together into rigid frames. The name comes from the red oxide primer traditionally applied to the beams. This is the construction used for warehouses, factories, aircraft hangars, large retail buildings and big agricultural arenas. Its defining strength is span: a rigid frame can cross very wide spaces with no interior columns and can be engineered for heavy extra loads such as overhead cranes or mezzanines.

What is a tubular steel building?

A tubular steel building is framed with galvanized steel tubing formed into bows or trusses and legs, with steel roof and wall panels fastened to the frame. It is the construction behind metal carports, garages, RV covers, barns and most residential and small-farm workshops. On our buildings the standard frame is 14-gauge tubing, with thicker 12-gauge available, and every structure is engineer-certified for the snow load and wind at its location.

Red iron vs. tubular steel: the differences that matter

Size and clear span

Tubular steel covers the sizes most property owners need. The workshops we install, for example, run up to 60 feet wide and 100 feet long. Red iron takes over beyond that range, or when a building needs very tall eaves, crane rails or heavy suspended loads.

Foundation

A red iron frame concentrates large loads at each column, so it requires an engineered concrete foundation with anchor bolts cast in exactly the right places before the steel arrives. A tubular building spreads its load along a base rail and can be installed on concrete, asphalt, gravel or level ground with the appropriate anchors. That flexibility alone can change a project budget significantly. Our anchoring guide explains the options.

Delivery and installation

Tubular buildings are delivered and assembled by a small crew with hand tools, typically in a day for most structures; our usual lead time is 2 to 5 weeks, weather permitting. Red iron buildings are usually sold as kits that must be erected with lifting equipment by a separate erection crew or contractor, after the foundation has cured, and the overall schedule is measured in months rather than weeks.

What is included

A red iron quote is often for the building package only: steel delivered to the site, with foundation, erection, doors and insulation contracted separately. Our prices include delivery and installation. When you compare the two, make sure you are comparing the finished building, not a kit against an installed structure.

Corrosion protection

Tubular frames are galvanized, which gives the steel a sacrificial zinc coating. Red iron beams are typically protected by primer paint. Both rely on the roof and walls to keep the frame dry. For how galvanizing works, see does galvanized steel rust.

Cost

For small and mid-size buildings, tubular steel is generally the more economical route once foundation and erection are counted, because it avoids the engineered foundation and crane work. As buildings get very large, red iron becomes the appropriate and efficient system. Prices for both move with the steel market, so compare current, complete quotes.

You probably need red iron if…

• The building must be wider than tubular framing allows, with no interior supports
• You need an overhead crane, heavy mezzanine or other large structural loads
• It is a commercial or industrial facility with code requirements specific to that occupancy
• You want very tall sidewalls for large equipment or aircraft

In those cases, talk to a red iron manufacturer and a local erector. That is not a building we supply.

Tubular steel is usually the better fit if…

• You are building a carport, garage, RV cover, barn or workshop for a home, hobby or farm
• You want it installed quickly, by the company you bought it from
• You would rather not pour an engineered foundation before you can start
• You want the option to add a lean-to or extra bays later — see our lean-to guide

Typical examples are a steel workshop, a metal garage or a barn-style equipment building.

Where pole barns fit in

There is a third option in this conversation: the wood post-frame building, or pole barn. It competes with tubular steel at small and mid sizes and with red iron for large agricultural buildings. We compare it in detail in pole barn vs. metal building.

Questions to ask any steel building supplier

• Is the frame red iron or tubular, and what gauge or beam size?
• Is the building engineered and certified for my county's snow and wind loads?
• Does the price include delivery, installation, doors and anchors?
• What foundation is required, and who designs it?
• What are the rust-through and workmanship warranties?

Frequently asked questions

Why is it called red iron?

Because the structural steel beams are traditionally coated with a red oxide primer. The frame is steel, not iron.

Is red iron stronger than tubular steel?

Red iron frames can carry heavier loads over longer spans. For garages, carports and typical workshops, a properly engineered tubular frame is designed for the loads those buildings actually see.

Does Wisconsin Carports sell red iron buildings?

No. We install galvanized tubular steel buildings and do not offer red iron or wood structures.

Can a tubular steel building be used as a commercial shop?

Many small businesses use them for storage, equipment and work space. Commercial use can bring additional local code requirements, so check with your building department first.

Find out if tubular steel fits your project

Tell us the size and use you have in mind. If a tubular steel building is right for it, we will quote it installed; if it is not, we will tell you. Request a free quote, design it yourself in 3D, or call (262) 383-4347.

This guide is general information. Structural requirements, size limits, pricing and commercial code or permit rules must be confirmed for your property with a Wisconsin Carports Building Specialist and your municipality.

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