The Texas metal building guide
Last checked September 2026.
- Where your land sits decides everything
- Why Texas counties cannot zone your property
- When a permit is still required
- City limits, ETJ, and open county
- Wind speed and what it means for your building
- The fourteen coastal counties and the WPI-8
- What to settle before you sign
Where your land sits decides everything
This guide is about tubular steel buildings, the kind built on your site by a crew out of galvanized tube and roll-formed panel. Carports, garages, barns, shops and RV covers. Not red iron, not wood sheds, and not a finished building delivered on a trailer. The rules differ.
Before gauge, before colour, before price, one thing sets the rules for your building: whether your land is inside a city limit or on unincorporated county land. Almost every wrong answer in this trade comes from mixing the two up.
On unincorporated land you are dealing with a county, and a Texas county can only do what state law lets it do. Inside a city limit you are dealing with a city, and Texas cities have broad powers, including zoning.
Why Texas counties cannot zone your property
A Texas commissioners court cannot pass ordinances except where state law explicitly allows it, and the legislature has never granted counties a general zoning power. There is no county zoning district, no county setback, and no county design review on unincorporated land.
This surprises people who have moved from other states. It is also the single best thing about building on open Texas land: where the building sits is your call.
When a permit is still required
Not being able to zone is not the same as having no say. Many Texas counties take part in the National Flood Insurance Program, and staying in it means regulating development across the county rather than only inside a mapped flood zone. Their definition of development is broad enough to cover putting up a structure, and a tubular steel building is put up on your site by a crew, so it sits squarely inside that definition.
The thresholds differ and they are worth knowing. Brazoria County starts at 200 square feet. Fort Bend County requires a permit for the construction of any new structure of 400 square feet or more, which a twenty by twenty carport meets exactly. Harris County requires a permit for all development and names carports and garages in its own list. Ellis County names carports too.
A few counties draw the line at walls rather than size. San Patricio County exempts an open carport, saying only structures with four walls and 200 square feet or larger need a permit, while a shed or storage building moved onto the property needs one before it is moved. If your building is open sided, ask your county that question specifically.
Plenty of counties require nothing. Parker, Wise, Lubbock, Smith, Williamson and Victoria all state in writing that they issue no building permits for this kind of work.
Chapter 233, Subchapter C of the Local Government Code is widely cited as making a permit necessary when a pre-built structure is placed on a property. Read it and that is not what it says. Subchapter C is titled Fire Code in Unincorporated Area. Section 233.061 opens it only to a county over 250,000 people or a county adjacent to one. Section 233.062(a) limits it to commercial establishments, public buildings and multifamily dwellings of four or more units. Section 233.063 requires a permit to construct or substantially improve one of those. A single family carport is outside all of it. That line traces back to one county's own summary.
Separately, Subchapter F applies the International Residential Code in the unincorporated areas of certain counties. El Paso County cites it directly and runs a commencement notice plus three named inspections. McLennan County runs the same shape: you tell the county what you are building and which code edition you used, and inspections follow. Neither is a permit you apply for.
City limits, ETJ, and open county
Inside a city limit, expect a zoning district, setbacks, lot coverage limits and a building permit. General law cities have limited powers; home rule cities, which are cities over 5,000 that adopt a charter, have broad ones.
Cities also reach into a band of land outside their limits called the extraterritorial jurisdiction. If your land sits just outside the sign, do not assume you are clear. Ask.
Wind speed and what it means for your building
Design wind speed comes from ASCE 7 and it follows your address, not your county line. Texas spans a wide range, from roughly 90 mph in parts of West and North Texas to 140 mph and above within a mile of the Gulf.
Every county page on this site shows a regional band for context and links the address lookup. Use the lookup before you sign anything. A quote engineered for the wrong wind speed is not a bargain, it is a rebuild.
The fourteen coastal counties and the WPI-8
The Texas Department of Insurance designates a catastrophe area covering fourteen first tier counties plus certain municipalities in Harris County east of State Highway 146. Inside it, a structure that needs wind and hail coverage through TWIA must be built and inspected to the specifications TDI adopts, and TDI issues a certificate of compliance called a WPI-8.
The rule has applied since 1 January 1988 and covers new work, additions, alterations and roof replacement. If you are in those counties, get the inspection priced into the quote.
What to settle before you sign
- Is the site inside a city limit, in an ETJ, or open county.
- Does the county require a development permit or a building permit to set a building here.
- What is the design wind speed at the address, not the county.
- Is the site in a FEMA floodplain.
- How far is the slab from any septic field.
- Does the quote include anchoring suited to that wind speed, or is it a base spec.