Harris County . TDI windstorm area
Sealed Engineering Letters in Houston, Texas
Harris County puts three separate engineering problems on the same address: expansive Beaumont clay under the slab, high coastal wind overhead, and a windstorm boundary that runs through the county itself.
Opening soon
Sealed Engineering is not yet accepting orders. Firm registration is pending with the Texas Board of Professional Engineers and Land Surveyors, and no engineering services are being offered or performed under this brand until it is granted. Founding customers on the waitlist are contacted first when ordering opens.
What governs engineering work in Houston
- County
- Harris County
- Region
- Gulf Coast
- Design wind speed
- roughly 130 to 140 mph basic wind speed
- Houston sits far enough inland to escape the highest coastal values and far enough south to stay well above the interior. Exposure is usually B in the developed core and moves to C on the outskirts.
- Soil
- Beaumont clay and Lake Charles clay, highly expansive
- Plasticity index across much of the county is high enough that seasonal shrink and swell is the default explanation for residential foundation distress, not the exception.
- Residential plan review
- Building Code Enforcement at the Houston Permitting Center
- The Planning and Development Department performs the site plan review step separately. Unincorporated Harris County is reviewed by the Harris County Engineering Department, and the two do not ask for the same things.
- TDI windstorm area
- Yes, WPI-8 certification applies
Before you submit in Houston
All plans are submitted electronically through the iPermits portal.
Department name and submittal details verified against the city's own site on . Municipalities reorganize, so confirm before relying on it for a deadline.
Wind speeds are the ASCE 7 band for the area and are given as planning context. Every sealed document uses the value looked up for the specific site address, along with the exposure category that actually applies to that site.
Engineering in Houston, in practice
The single most important thing to know about engineering work in Harris County is that the Texas Department of Insurance windstorm boundary runs through it. TDI describes the designated catastrophe area as covering parts of Harris County east of Highway 146, and names La Porte, Morgan's Point, Pasadena, Seabrook, and Shoreacres among the areas covered, while the rest of the county sits outside it. A reroof inside that area needs a certificate of compliance and the identical reroof outside it does not.
Foundations here are a moisture problem before they are a structural one. Beaumont clay swells and shrinks by a large fraction of its volume across a wet spring and a dry August, and Houston gets both in the same year. A relative elevation survey on a Houston slab taken in May and taken in September will differ on a foundation that is behaving exactly as designed, which is why an inspection report that reads the season is worth more than one that only reads the number.
Rooftop solar volume in the Houston metro is heavily driven by installers working across dozens of jurisdictions at once. The city, the county, and every incorporated suburb from Pearland to Cypress to Katy have their own plan review, and the structural letter that satisfies one is not automatically formatted for the next. The address, the framing, and the array layout are what change the analysis; the code edition adopted locally is what changes the letter.
Flat terrain and a high water table shape the rest of it. Drainage is a structural item here in a way it is not in the Hill Country, and a foundation report that does not look hard at grade, gutter discharge, and where irrigation is placed has skipped the most likely cause of what it just measured.
What Houston orders most
Ordered by local weight rather than alphabetically. Every deliverable in the catalog is available for a Houston address; these are the ones this market actually asks for.
- Site visit requiredFoundation Inspection ReportsAn independent engineering opinion on what a foundation is actually doing: a relative elevation survey, documented distress, and a conclusion that is not written by anyone selling piers.What it contains
- Document reviewSolar Structural LettersThe stamped letter your plan reviewer asks for before a rooftop array goes on: existing framing capacity, wind uplift at the actual site, and attachment spacing that resists it.What it contains
- Site visit requiredWPI-8 Windstorm CertificationsThe Texas Department of Insurance certificate of compliance that windstorm coverage depends on, obtained through the licensed engineer path rather than the TDI inspector queue.What it contains
- Site visit requiredFoundation Repair PlansThe repair designed before it is bid: pier type, locations, depth, and design load specified by an engineer who is not selling the piers.What it contains
- Site visit requiredRoof Certification LettersThe letter an underwriter asks for when the appraiser flags the roof: condition observed, deficiencies named, and an estimate of remaining useful life, sealed by an engineer.What it contains
Houston questions
Is my Houston address inside the windstorm area?
It depends where in the county it sits. TDI describes the catastrophe area as covering parts of Harris County east of Highway 146, and names La Porte, Morgan's Point, Pasadena, Seabrook, and Shoreacres among the covered areas. Most of the rest of the county is outside it. Because the department defines this by area rather than by one clean line on a map, confirm a specific address with TDI rather than assuming: the consequence of guessing wrong is a windstorm coverage gap.
Why does my Houston slab crack every summer?
Almost certainly the clay. Beaumont clay loses volume as it dries and the perimeter of a slab dries faster than the center, which lifts or drops corners seasonally and shows up as diagonal cracking at door and window corners. That pattern is extremely common here and frequently within what the structure tolerates, which is what an elevation survey is for.
Do I file with the City of Houston or with Harris County?
It follows the address, not the mailing city. An address inside Houston city limits is reviewed at the Houston Permitting Center. An address with a Houston mailing address in unincorporated Harris County is reviewed by the Harris County Engineering Department. A great many properties in the metro are the second case despite the mail saying Houston.
Nearby Texas markets
Sealed documents for Houston property
Tell us the address and the document you have been asked for. Houston sits in Harris County, and both the wind values and the reviewing office follow from that.
Opening soon. Founding customers get first turnaround slots.