Metal Carport vs Steel Building: Which One Fits Your Liberty Hill Property?

Metal carport vs steel building is a decision most Liberty Hill landowners make backward. They pick a size first, then find out what the structure can and cannot do. The better order is to answer five plain questions about walls, span, ground, jurisdiction and future plans. The answers pick the structure for you.

Short verdict first. If all you need is shade and hail cover over vehicles, and you will never add walls, a carport does the job. If you want it locked, wide, insulated, wired, or bigger later, you are describing a steel building, and it should be designed as one from the anchor bolts up.

What actually separates a metal carport from a steel building?

A metal carport is an open roof on posts. A steel building is an enclosed frame tied to a foundation designed for it. The sheet metal can be identical on both. The difference is the load path: how wind, hail and the weight of the roof travel through the frame and into the ground.

Carport describes a use, not a way of building. Two very different products get sold under that name:

• Tube-frame kit carport. Roll-formed galvanized square tubing, commonly 2.5 inch in 14 gauge with a 2.25 inch 12 gauge option, slip-fit and screwed together. Legs sit on a base rail roughly every 5 feet. The roof is usually 29 gauge sheeting. It is held down with rebar pins or auger anchors in dirt, or wedge anchors in an existing slab.
• Welded carport. Tube steel or schedule 40 pipe columns set in concrete piers, welded trusses or beams, purlins, and a 26 gauge R-panel roof. It is built like a small steel building with the walls left off.

Steel buildings come in two common forms as well:

• Weld-up building. Tube or pipe columns, welded trusses, cee purlins and girts, fabricated to fit the site.
• Rigid-frame building, often called red iron. I-beam columns and rafters, either W-shapes or built-up tapered members, bolted together. Bays commonly run 20 to 25 feet. Cee or zee purlins and girts carry the sheeting. Anchor bolts are cast into the concrete from an anchor bolt plan.

So the honest comparison is not carport against building. It is a light open frame against an engineered enclosed frame, with the welded carport sitting between them.

Planning something like this? Send the shop your drawings for a written quote.

Five questions that decide it

Work them in order. The first answer that points to a building usually settles the matter.

1. Will it ever have walls?

Wind design sorts structures by enclosure. ASCE 7, the national standard for design loads, classes a structure as open, partially enclosed or enclosed, and the pressures change with the class. An open roof takes uplift from below, like a wing. A three-sided structure is the hard case. Wind gets in, cannot get out, and pushes up on the roof from inside while suction pulls from outside. ASCE 7 assigns a partially enclosed building roughly three times the internal pressure coefficient of an enclosed one.

• If it stays open on all sides for good: a carport works.
• If you plan to sheet one or two sides against west sun or a north wind: say so before anything is drawn. Posts, bracing and anchors change.
• If it gets three sides, or four walls and doors: you want a steel building. Do not sheet in a kit carport later and assume the frame was sized for it.

2. How wide is the clear span, and how tall is the eave?

• If the span is about 24 feet or less: either structure can do it.
• If the span is 24 to 30 feet: kit carports reach this on paper, but light tubing is working hard at that width. Welded trusses or a rigid frame are the better answer.
• If the span is over 30 feet, or you need a clear floor for a tractor with implements, round bales or an RV with the slides out: steel building.

Twenty-four feet is also a number in Texas law. The Texas Engineering Practice Act exempts private dwellings, their garages and farm and ranch buildings from requiring a licensed engineer. Its exemption for other small one-story buildings generally stops applying once a clear span passes 24 feet on the narrow side. Being exempt under the statute does not mean the span is safe without design, and a city can still require stamped drawings. Confirm your case with a licensed engineer.

Height matters as much as width. The legal vehicle height limit in Texas is 14 feet, and a fifth wheel with roof air can stand over 13. Tall legs on a light frame rack easily in wind. A tall eave pushes you toward heavier columns and real piers.

3. What is under it?

Liberty Hill sits on the limestone side of I-35. Soil is thin, caliche is common, and rock ledge is often within a couple of feet of the surface. Farther east, toward Hutto and Taylor, the ground turns to Blackland clay that swells when wet and shrinks when dry. The ground changes the answer.

• If you have an existing 4 inch driveway slab: it was poured to park on, not to hold a roof down. Wedge anchors set near a slab edge can break the concrete out under uplift. A light carport may be fine. Anything heavier needs piers cut in beside or through the slab.
• If you have bare ground with shallow rock: rebar pins will not drive and auger anchors will not turn in limestone. The standard dirt anchors for a kit carport often cannot be installed correctly here. Piers drilled into rock give excellent bearing and hold-down, but they take a rock auger.
• If you are pouring a new slab: choose the structure first. A clear-span rigid frame pushes outward at the column bases, and the foundation has to resist that thrust, usually with hairpin rebar or ties into the slab. Anchor bolts go in before the pour, from the plan. The same logic is laid out in the guide to what to decide before you pour the slab for a barndominium steel frame.
• If you are on clay: expect an engineered slab or deeper piers, whichever structure you pick.

4. Who has jurisdiction over the tract?

• If you are inside city limits: plan on a permit and a setback check.
• If you are in the ETJ or unincorporated county: fewer building permits, but floodplain, septic and driveway rules still apply.
• If the tract is deed restricted: read the restrictions before you read anything else.

The permit section below covers each branch.

5. What will you want from it in five years?

• If the answer is the same cover and nothing more: a carport.
• If you may add bays: order a rigid frame with an expandable endwall. That means a full frame at the end instead of a light post-and-beam endwall, so the next bay bolts on.
• If you may add a lean-to: the main columns have to be designed for that load now, not later.
• If you want a concrete floor, power, insulation or roll-up doors: steel building. Door openings need framed jambs and a header. Insulation needs a closed envelope.

The expensive mistake here is buying twice. A carport that gets torn down three years later to make room for the building you needed all along is the worst outcome on the list.

Does a metal carport or steel building need a permit in Liberty Hill?

Inside Liberty Hill city limits, expect a building permit for either one, and confirm with the city building department before steel is ordered. In unincorporated Williamson County, a building permit is usually not the hurdle. Floodplain, septic and driveway rules are. Either way, check your own tract. What follows is how it generally works in Texas, not a ruling on your property.

• Cities adopt building codes and issue permits. The model International Residential Code exempts one-story detached accessory structures up to 200 square feet from a permit, and cities amend that number. A two-car carport at 20 by 20 feet is 400 square feet. Setbacks, lot coverage and impervious cover limits can apply even where a permit does not.
• Texas counties have limited building code authority. In the unincorporated parts of Williamson, Travis and Burnet counties, county development services typically looks at floodplain development, on-site sewage facilities and driveway connections to county roads. You cannot build over a septic drain field or spray area. Commercial buildings often go through the county fire marshal as well.
• The ETJ is a gray zone. A city's subdivision and platting rules can reach into its extraterritorial jurisdiction even where its building permits do not. Call the city and the county both.
• Deed restrictions are private law. Many subdivisions around Liberty Hill, Leander and Georgetown limit metal buildings by size, placement or exterior finish. A property owners association can enforce that no matter what the county allows.
• Easements move the footprint. Much of the area is served by Pedernales Electric Cooperative. An overhead line or a utility easement on the plat decides where a structure can sit. Call 811 before any pier is drilled.
• Commercial work adds TDLR. The Texas Department of Licensing and Regulation administers the Texas Accessibility Standards, and commercial projects above a set value are registered and reviewed.
• Welding is governed by code, not by a state license. Texas does not issue a statewide welder license. Structural steel welding is done to AWS D1.1. Sheet steel thinner than 3/16 inch, which is where light carport tubing falls, has its own companion code, AWS D1.3. Ask which code the welds are made to.

Design loads come from ASCE 7. According to the NOAA National Severe Storms Laboratory, a thunderstorm is classed as severe when it produces hail 1 inch or larger or wind gusts over 50 knots, about 58 mph. The design wind speeds ASCE 7 assigns to Central Texas addresses are far above that, on the order of 105 to 115 mph depending on the code edition and the risk category of the building. Look up your own address in the ASCE Hazard Tool and have a licensed engineer apply the result.

One caution on kit carports sold as certified. A generic rating sheet is not engineering for your site. Ask for drawings sealed by a Texas-licensed engineer that show your wind speed and your anchoring method.

How long will a metal carport last next to a steel building?

Both can last for decades. Lifespan is set by steel thickness, coating and connection details, not by the name on the structure. A welded carport in heavy tube with a good coating will outlast a thin building with bad details. These are the items to check:

• Gauge. The lower the number, the thicker the steel. A 29 gauge panel dents in hail that a 26 gauge panel handles better. Dents are cosmetic until the coating cracks.
• Coating. G90 galvanized under ASTM A653 means 0.90 ounce of zinc per square foot, counted across both sides. Roof panels are often Galvalume, bare or painted. The red or gray shop primer on structural steel is a temporary coat, not a finish. Red iron left exposed on an open carport needs a real paint system or galvanizing.
• Welds and cut ends. Every field weld and saw cut burns or removes the zinc. Those spots need zinc-rich primer. Rust starts there first.
• Fasteners. Exposed roof screws seal with a rubber washer. Texas heat and sun dry those washers out, and they are usually the first maintenance item on any metal roof.
• Post bases. Steel fails where it meets the ground. Posts buried in dirt rust at grade. On a ranch, manure and urine speed that up. Set posts on piers that stand above grade, with base plates, or sleeve the concrete up out of the dirt.
• Wind. Open carports usually fail by uplift at the anchors, not by the frame folding. Enclosed buildings usually get hurt through a large door left open in a storm.

Three hypothetical properties, run through the tree

These are illustrations, not real customers or jobs.

1. A half-acre subdivision lot in Liberty Hill, two trucks, existing driveway. Open for good. Span around 20 feet. Existing slab. City limits and deed restrictions. Result: a welded carport on piers set beside the slab, after the permit and the association approval are in hand. The restrictions may rule out a kit carport on appearance alone.
2. Twelve acres off a county road near Bertram, a fifth wheel, a tractor, and a shop planned for later. Tall eave. Walls coming. Future expansion. Result: a steel building, even if phase one is roof only. Build the frame, piers and anchor bolts for the enclosed building, sheet the roof now, add walls later. Tell the engineer about the phasing, because the roof-only stage is its own wind case.
3. A hay cover outside Burnet, 40 foot clear span, open sides. The use is agricultural and the sides stay open, but the span decides it. Result: an open-sided steel building with an engineered frame. The farm and ranch exemption in state law does not make a 40 foot span safe without design.

What should you hand a fabricator before a carport or steel building gets drawn?

A fabricator can only quote what is described. Bring these seven items and the conversation goes faster.

1. The site. Address, a photo, where the structure sits on the tract, the slope, and truck access.
2. The size. Footprint, eave height, clear door openings, and the tallest thing that will go under it.
3. The enclosure. Open, partly sheeted or closed in, both now and later.
4. The ground. Existing slab and its thickness if known, how shallow the rock is, and who is pouring concrete.
5. The jurisdiction. City, ETJ or county, any deed restrictions, and whether stamped drawings are required.
6. The finish. Galvanized or primed and painted, panel gauge and color.
7. The date. When you need it standing.

TG Welding in Liberty Hill builds steel buildings and covered structures set on the customer's slab, along with pergolas and other outdoor structures. How a job runs at the shop matches the list above: send drawings, a sketch or a photo with the site, scope and date, get a written quote back in days, and the work is built on a PO in the Liberty Hill bay, then loaded out or installed on site by the crew. You can look through completed steel work, or keep reading with the landowner's guide to planning a steel building or metal shop in Central Texas.

Carport and steel building questions landowners ask

Can I enclose a metal carport later and turn it into a garage?

Sometimes, but not by default. Adding walls changes the wind loads on the frame and the anchors, and a three-sided structure is the hardest case. Have a licensed engineer check the frame and foundation first. If walls are likely, design for them on day one.

Do I need an engineer for a carport in Texas?

State law exempts private dwellings, their garages and farm and ranch buildings from requiring a licensed engineer, but a city permit office, a wide span or a tall eave can still call for sealed drawings. Ask your city or county, and ask an engineer when the span passes about 24 feet.

Can a carport go on my existing driveway slab?

A light one often can. A typical 4 inch driveway slab was not designed to resist uplift, and anchors near the edge can break out. Heavier carports and all steel buildings should sit on piers or a foundation designed for the column loads.

Will a metal carport hold up to Central Texas hail and wind?

It will if the gauge, anchoring and design wind speed match the site. Thicker panels dent less. Proper piers or rock anchors resist uplift. Ask for engineering that names your wind speed, not a generic rating sheet.

How tall should an RV cover be?

Measure the rig with roof air and antennas, then add working clearance. The legal vehicle height limit in Texas is 14 feet, so many owners plan for a clear opening at or above that. Tall eaves need heavier columns and proper piers.

Frequently asked questions

Can I enclose a metal carport later and turn it into a garage?

Sometimes, but not by default. Adding walls changes the wind loads on the frame and the anchors, and a three-sided structure is the hardest case. Have a licensed engineer check the frame and foundation first. If walls are likely, design for them on day one.

Do I need an engineer for a carport in Texas?

State law exempts private dwellings, their garages and farm and ranch buildings from requiring a licensed engineer, but a city permit office, a wide span or a tall eave can still call for sealed drawings. Ask your city or county, and ask an engineer when the span passes about 24 feet.

Can a carport go on my existing driveway slab?

A light one often can. A typical 4 inch driveway slab was not designed to resist uplift, and anchors near the edge can break out. Heavier carports and all steel buildings should sit on piers or a foundation designed for the column loads.

Will a metal carport hold up to Central Texas hail and wind?

It will if the gauge, anchoring and design wind speed match the site. Thicker panels dent less. Proper piers or rock anchors resist uplift. Ask for engineering that names your wind speed, not a generic rating sheet.

How tall should an RV cover be?

Measure the rig with roof air and antennas, then add working clearance. The legal vehicle height limit in Texas is 14 feet, so many owners plan for a clear opening at or above that. Tall eaves need heavier columns and proper piers.