Metal Building Permits and Wind Zones in Texas: A Dealer’s Guide

Texas is the second largest market in the metal building industry and the most confusing one to sell into. Not because the rules are strict, but because there is no single set of them. A dealer who understands how Texas actually works has a real advantage over one who assumes it behaves like every other state.

There is no enforced statewide building code

Texas sets a floor, not a ceiling. State law adopts the International Residential Code as it existed on May 1, 2012 as the municipal residential code, and the International Building Code from the same date for commercial work. Cities are then free to amend, and many have adopted far newer editions by ordinance.

So the honest answer to "what code applies in Texas" is: whatever your city adopted. Never assume an edition without checking that city's ordinance.

Inside city limits versus outside changes everything

This is the part that surprises out-of-state dealers. Texas counties generally do not issue building permits or perform inspections in unincorporated areas. McLennan County states outright that it "does not have inspection authority or responsibility and can not charge fees."

Some counties do have limited authority for non-residential work. Bexar County, for example, requires a permit when a pre-built building is placed on a property in unincorporated areas. So "counties do not permit in Texas" is a useful rule of thumb and a bad thing to promise a customer.

The coast is a different country

The Texas Department of Insurance designates a catastrophe area covering 14 first-tier coastal counties: Aransas, Brazoria, Calhoun, Cameron, Chambers, Galveston, Jefferson, Kenedy, Kleberg, Matagorda, Nueces, Refugio, San Patricio and Willacy, plus parts of Harris County east of Highway 146 including La Porte, Morgan's Point, Pasadena, Seabrook and Shore Acres.

That area is split into three wind zones: Seaward, Inland I and Inland II.

WPI-8 is insurance, not a permit

This distinction has cost coastal buyers real money. To get wind and hail coverage through the Texas Windstorm Insurance Association, a property owner in the catastrophe area needs a Certificate of Compliance showing the structure meets the applicable windstorm code.

There are two routes. A WPI-8 is issued by TDI through an inspection process that starts before construction begins. A WPI-8-C is issued by TWIA for completed work certified by a Texas-licensed professional engineer.

TWIA's own list of improvements commonly requiring certification includes new structures, additions, and decks and patio covers. It does not name carports explicitly, and TDI's rules do not mention carports, canopies or accessory structures anywhere. For a specific structure, call TDI Engineering rather than guessing.

Which code applies on the coast right now

TDI ties coastal compliance to specific I-Code editions by construction date. Structures built on or after September 1, 2020 fall under the 2018 IRC and IBC. Structures built on or after April 1, 2026 fall under the 2024 IRC and IBC, which reference ASCE 7-22 and brought revised hurricane coastline wind contours from the Carolinas through Texas.

Note what changed in how the rules are written. The older rule stated explicit speeds: 130 mph seaward, 120 Inland I, 110 Inland II, all under ASCE 7-05. The current rules state no mph at all. They point to the wind maps in the referenced code edition instead. If someone quotes you a flat Texas coastal mph figure today, ask where it came from.

What about inland Texas?

Here is where we will be straight with you rather than fill space. There is no authoritative published mph figure for Dallas, Austin, San Antonio or Lubbock that we were able to verify from a government source, and we are not going to invent one. Look the site up in the ASCE Hazard Tool or read it off the map figures in your adopted code edition.

What this means for selling into Texas

Texas rewards dealers who ask two questions before quoting: is this inside city limits, and is this in a coastal county. Those two answers determine whether the customer needs sealed plans, whether anyone will inspect, and whether a missed windstorm inspection is about to make their new building uninsurable.

If your quoting process cannot capture the install location and branch on it, your team will discover these facts on the follow-up call instead, which is the expensive place to find them.