Steel Carport: Frame Gauge, Coating, Parts and 2026 Prices
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A steel carport is an open-sided roof on a galvanized steel frame. Carport.com and Alan's Factory Outlet list a 14-gauge frame as standard and 12-gauge as the upgrade, and 12-gauge is 40.0 percent thicker on the gauge chart. Listings read on 2026-10-06 run from $349.99 to $10,200.20.
What is a steel carport made of? #
A steel carport is built from a galvanized steel frame, beams, roof panels and anchors, and sellers state the frame gauge and the roof panel gauge separately.
Gauge is a number for the thickness of sheet and tube. It is neither a standard nor a metric unit, and it runs backward, so a lower number is a thicker wall. Galvanized means steel with a zinc coat.
Carport.com lists the standard frame as 14-gauge galvanized American steel and the roof and wall sheeting as 29-gauge. Alan's Factory Outlet lists a 14-gauge frame as standard and 12-gauge as optional.
| Part | What it does | What sellers state |
|---|---|---|
| Frame tube (legs and posts) | Carries the roof to the ground | 14-gauge standard and 12-gauge upgrade (Carport.com, Alan's) |
| Beams and roof ribs | Span the legs and hold the roof panels | No seller read lists them as a separate part |
| Roof panel | Sheds rain and snow | 29-gauge roof and wall sheeting (Carport.com); 26-gauge in Florida (Alan's) |
| Coating | Slows rust | "Galvanized" (Carport.com, American Metal Buildings). No seller read states the coating weight or how the frame was coated. |
| Anchors | Hold the frame to the ground | "Even the strongest frame can fail with poor anchoring" (Direct Metal Structures) |
| Roof style | Sets the look and drainage | Regular, boxed eave and vertical (Alan's); regular, A-frame and vertical (American Metal Buildings) |
Parts and gauges are as each seller lists them on the date shown. Ask the seller for the frame gauge, the roof panel gauge and the coating in writing before you order.
Steel against aluminum and wood
Steel is 2.87 times as stiff as aluminum and 2.91 times as dense. The modulus of elasticity is 29,000 ksi for steel against 10,100 ksi for aluminum, and the density is 7.86 g per cm3 against 2.70. These are material properties as cited on the aluminum carports page, not carport ratings.
Wood frames are covered under wood carports.
The carport material comparison lines up steel, aluminum and wood.
How thick is the steel in a steel carport? #
The 14-gauge wall is 0.0747 in and the 12-gauge wall is 0.1046 in on the mild-steel gauge chart, so 12-gauge is 40.0 percent thicker.
The chart is from Metal Supermarkets, which prints one column for mild steel and one for galvanized steel. The galvanized column gives 0.0785 in and 0.1084 in, which is 38.1 percent thicker.
A Direct Metal Structures blog dated 2025-09-17 prints about 0.083 in and about 0.108 in, which is 30.1 percent thicker. Elite Metal Structures, dated 2022-08-31, gives only a rough gap between the two gauges, and the chart difference is 0.0299 in.
| Source and basis | 14-gauge (in) | 12-gauge (in) | Percent thicker |
|---|---|---|---|
| Mild steel chart (Metal Supermarkets) | 0.0747 | 0.1046 | 40.0 |
| Galvanized steel chart (Metal Supermarkets) | 0.0785 | 0.1084 | 38.1 |
| Seller blog (Direct Metal Structures, 2025-09-17) | about 0.083 | about 0.108 | 30.1 |
| Seller blog (Elite Metal Structures, 2022-08-31) | Not printed | Not printed | Says "roughly 0.03 inches apart"; chart difference is 0.0299 in |
| 29-gauge roof sheet | Not on the chart | Not on the chart | The chart ends at 28 gauge, so no thickness is printed |
A 29-gauge roof sheet is a different sheet from the frame wall. Carport.com lists 29-gauge roof sheeting, and the chart ends at 28 gauge, so no 29-gauge thickness is printed here.
Gauge numbers are not a standard, so the decimal wall in inches is the figure to compare between sellers.
For the full gauge decoder across metal carports, see the metal carport gauge and coating guide.
The outside size of the tube is a separate question, covered on the carport tube size page.
Seller pages read from 2026-10-05 to 2026-10-07. Wall thickness from the Metal Supermarkets mild-steel chart.
What protects a steel carport from rust, and where does it stop? #
Zinc coating protects a galvanized steel carport from rust by covering the steel, and the protection is limited at scratches and cut edges.
The American Galvanizers Association and GalvInfo describe what an intact coat, a scratch, a cut edge and the end of the nearby zinc do.
| Place on the steel | What the sources say | Source |
|---|---|---|
| Intact coat | Galvanizing "limits corrosion by eliminating contact between corrosive elements and the steel." | American Galvanizers Association |
| Scratch or coating defect | Zinc protects small areas of exposed steel, but that protection is "limited by the width of the damaged area." The maximum distance the AGA reports is slightly greater than 1/4 inch (7 mm). | American Galvanizers Association |
| Cut edge | Galvanic action between zinc and steel under atmospheric exposure "extends only a very short distance." | GalvInfo Note 3.6 |
| Test: 1 mm sheet and 2.3 mm sheet | The edge of 1 mm sheet stayed almost free of red rust after 6 months. The edge of 2.3 mm sheet showed rust after 2 weeks. Frame walls on the chart are 1.9 mm (14-gauge) and 2.7 mm (12-gauge). | GalvInfo Note 3.6 and the gauge chart |
| After the nearby zinc is used up | Until the zinc near the cut edge has been consumed, the degree of rust changes very little. Protection ends when that zinc is gone. | GalvInfo Note 3.6 |
Quotations are from the American Galvanizers Association and GalvInfo. The cut-edge test used sheet steel, not carport tube.
Zinc protects a scratch or a cut edge only a short distance, and the cut-edge test used sheet steel, not tube, so the useful seller question is how the frame's cut ends are coated.
G90 is a coating weight of 0.90 oz per sq ft, both sides combined, in GalvInfo Note 1.1, and no seller read prints a coating weight for its frame.
Coating grades and how to buy a galvanized frame are covered on the page about galvanized steel carports.
Does the warranty on a steel carport change with the gauge? #
A rust-through warranty covers a frame against rusting through, and two of the five sellers read tie a 20-year term to 12-gauge steel.
| Seller (page date) | Tied to gauge? | Term as stated |
|---|---|---|
| Alan's Factory Outlet (2026-06-16) | Yes: optional 12-gauge framing and most roof panels | 20-year rust-through, plus a 1-year craftsmanship warranty |
| Metal America (read 2026-10-07) | Yes: 12-gauge frame | 20-year rust warranty instead of 10 |
| Carport.com (undated) | No: the frame | 20-year frame warranty |
| American Metal Buildings (2023-07-06) | Not stated | "Up to 20-Year Warranty"; the rust-through term is unclear |
| Home Depot VIWAT listing (2026-10-06) | Not stated | Not stated in the page read |
Alan's Factory Outlet prints 20 years on optional 12-gauge framing and most roof panels, and Metal America prints 20 years instead of 10 for a 12-gauge frame. Carport.com gives 20 years on the frame without naming a gauge, American Metal Buildings prints only an up-to-20-year headline, and the Home Depot listing states no term.
Compare the written warranty for your gauge before you order.
Warranty, wind and snow terms are as each seller lists them on the date shown. Local loads and your building department decide what a site requires.
How do sellers word wind and snow ratings for steel carports? #
Alan's Factory Outlet lists 150 mph wind and 35 psf snow as standard for its steel carports and 170 mph and 50 psf as upgrades, where psf means pounds per square foot.
| Seller (page date) | Rating wording | 12-gauge advice |
|---|---|---|
| Alan's Factory Outlet (2026-06-16) | 150 mph and 35 psf standard; 170 mph and 50 psf upgrades | 12-gauge frame is an optional upgrade |
| Carport.com (undated) | No figure; engineer certification available where a permit requires it | The 12-gauge frame is the upgrade for heavier snow or wind |
| Carport Commander (modified 2024-10-23) | No figure; "higher snow load and wind load ratings" for 12-gauge | Heavy snow, high wind, buildings 10 ft and taller or more than 30 ft wide |
| Elite Metal Structures (2022-08-31) | No figure | Buildings taller than 10 feet or wider than 30 feet |
| Direct Metal Structures (2025-09-30) | No rating; engineered drawings show a design meets load requirements | Spans of 32 to 40 ft against up to 30 ft |
Sellers rate their own models in different forms, one prints a mph and psf figure, none names a code edition, and certification is a separate item to ask for.
Carport.com lists engineer certification where a permit requires it, and Direct Metal Structures says a certified building comes with engineered drawings.
Warranty, wind and snow terms are as each seller lists them on the date shown. Local loads and your building department decide what a site requires.
How much does a steel carport cost? #
Steel carport listings read on 2026-10-06 run from $349.99 to $10,200.20, a spread of 29.1 times.
| Listing | Size and area | Price | Per sq ft | What the listing covers |
|---|---|---|---|---|
| Walmart (Patiowell), metal carport with vertical roof, 10x15 (read 2026-10-06) | 10x15 ft (150 sq ft) | $349.99 | $2.33 | Sale tile (was $660); delivery and assembly terms not read |
| Home Depot (VIWAT), metal carport, 20x20 (read 2026-10-06) | 20x20 ft (400 sq ft) | $1,100 | $2.75 | Free delivery; assembly terms not read |
| Alan's Factory Outlet, vertical roof, 20x20 (read 2026-10-06) | 20x20 ft (400 sq ft) | $1,995 | $4.99 | Free set up and delivery (listing title) |
| Alan's Factory Outlet, regular roof, 24x25 (read 2026-10-06) | 24x25 ft (600 sq ft) | $2,495 | $4.16 | Free set up and delivery (listing title) |
| American Metal Buildings, steel carport, 24x20 (read 2026-10-06) | 24x20 ft (480 sq ft) | $5,000 | $10.42 | Free delivery (listing) |
| American Metal Buildings, utility motorhome carport (24x35x12), 24x35 (read 2026-10-06) | 24x35 ft (840 sq ft) | $10,200.20 | $12.14 | Price in the listing; delivery terms not read |
Per square foot the six rows run $2.33 to $12.14, computed as the listed price over width times depth. Rows that include delivery or setup are not comparable with rows that do not.
Cost guides give other ranges. HomeGuide, updated 2026-01-16, gives $8 to $15 per sq ft installed for steel. Alan's Factory Outlet, modified 2026-06-16, gives a roof-only average of $4.56 to $5.74 per sq ft. Eagle Carports, modified 2025-09-25, says most metal carports cost $3,000 to $10,000.
The guides disagree with each other and with the listings because they price different areas, roof styles and inclusions.
Confirm current requirements with your local building department before beginning construction. Prices change; each row shows its read date.
What roof styles and sides can a steel carport have? #
A steel carport comes in regular, boxed eave and vertical roof styles at Alan's Factory Outlet, and in regular, A-frame and vertical styles at American Metal Buildings.
Alan's describes regular as the most economical style, boxed eave as an A-frame look with horizontal roof panels, and vertical as vertical panels. Its roof-only averages, modified 2026-06-16, are $4.56 per sq ft for regular, $5.01 for boxed eave and $5.74 for vertical.
A steel carport can have open sides, partial sides or full enclosure. Carport.com prints 29-gauge sheeting for the roof and, when enclosed, the walls. Eagle Carports lists walls and doors at $800 to $3,000 plus on top of the base price, on a page modified 2025-09-25.
Wider versions are covered under two-car metal carports.
What should you ask a seller before you buy a steel carport? #
A steel carport buyer can put eight questions to each seller, and the answers belong on the spec line before the quotes are compared.
Confirm current requirements with your local building department before beginning construction.
Steel carport questions (FAQ) #
A steel carport is an open-sided roof on a galvanized steel frame, sold as a kit or installed by the seller. Sellers list regular, boxed-eave and vertical roof styles. The roof panels are thinner steel than the frame.
Carport.com lists a 14-gauge frame with 29-gauge roof sheeting and a 12-gauge frame as the upgrade. On the mild-steel chart 14-gauge is 0.0747 in and 12-gauge is 0.1046 in. Sellers print other decimals for the same names, so ask for inches.
Galvanized steel carries a zinc coat that protects scratches and cut edges only a short distance. The protection ends where the nearby zinc is used up. Alan's Factory Outlet prints a 20-year rust-through warranty on optional 12-gauge framing and most roof panels.
Steel is stiffer and heavier. Its modulus is 29,000 ksi against 10,100 ksi for aluminum, and it is about 2.91 times as dense. Strength depends on the alloy, grade and section, and these figures are material properties, not carport ratings.
Each seller rates its own models. Alan's Factory Outlet lists 150 mph and 35 psf as standard and 170 mph and 50 psf as upgrades. Ask what the rating covers, who certifies it and which code edition it follows.
Listings read on 2026-10-06 run from $349.99 to $10,200.20. HomeGuide gives $8 to $15 per square foot installed for steel, and Alan's Factory Outlet gives a roof-only average of $4.56 to $5.74 per square foot.
The 12-gauge wall is thicker, 0.1046 in against 0.0747 in on the chart. Sellers tie it to heavier snow, higher wind or larger buildings in their own words, and none names a code edition. Compare the rust-through warranty for each gauge.
What to do next #
Start with the seller's spec line. Ask for the frame gauge and tube size, the roof panel gauge, the coating and how the frame was coated, the wind and snow rating and who certifies it, the rust-through warranty for your gauge, and what the price covers. Then compare quotes line by line, and confirm permit rules with your local building department.
More are in the CarportBay carport guides.
The tables report what each source states, so you can compare sellers on their own words before you ask for a price.
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Sources
Each figure is attributed to the page named, on the date shown. Seller and listing pages are cited by name and date. Wall thickness comes from the Metal Supermarkets mild-steel chart.
- Metal Supermarkets, sheet metal gauge chart, mild and galvanized columns (read 2026-10-05)
- GalvInfo, Note 1.1 Rev 4.0, zinc-based coatings on steel sheet (G90) (read 2026-10-05)
- GalvInfo, Note 3.6, galvanic and cut edge corrosion of galvanized sheet (read 2026-10-07)
- American Galvanizers Association, damaged galvanized steel and storage (read 2026-10-07)
- Alan's Factory Outlet, metal carport prices page (dated 2026-06-16; read 2026-10-07)
- Carport.com, metal carports page (read 2026-10-07)
- Metal America, carports article (read 2026-10-07)
- American Metal Buildings, metal carports page (dated 2023-07-06; read 2026-10-07)
- Direct Metal Structures, blog on 12-gauge and 14-gauge framing (dated 2025-09-30; read 2026-10-07)
- Elite Metal Structures, blog on 12 and 14-gauge steel framing (dated 2022-08-31; read 2026-10-06)
- Carport Commander, blog on 12-gauge and 14-gauge carport frames (dated 2024-10-23; read 2026-10-06)
- Home Depot, VIWAT 20x20 metal carport listing (read 2026-10-06)
- Walmart, Patiowell 10x15 metal carport listing (read 2026-10-06)
- HomeGuide, metal carport prices (dated 2026-01-16; read 2026-10-06)
- Eagle Carports, blog on metal carport prices (dated 2025-09-25; read 2026-10-06)
- Aluminum Design Manual, AISC Steel Construction Manual (14th ed.) and a University of Florida materials page, steel and aluminum density and modulus, as cited on the aluminum carports page (read 2026-10-05)
Seller pages read from 2026-10-05 to 2026-10-07. Wall thickness from the Metal Supermarkets mild-steel chart.
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Related guides
- galvanized steel carportsCoating, where rust starts and cost.