If your Houston property is in a Texas Windstorm Insurance Association (TWIA) eligible zone, your metal roof must meet specific Texas Department of Insurance (TDI) standards to qualify for windstorm coverage. This guide covers what's required, how certification works, and why metal roofing excels at meeting these requirements.
The WPI-8 form is a certificate of compliance that proves your roof was installed according to the Texas Windstorm Building Code. It must be filed by a licensed Texas engineer or certified inspector after installation. Without a valid WPI-8, your property cannot obtain TWIA windstorm insurance.
Minimum wind speed rating: 120 mph for most coastal Texas zones, 130+ mph for TWIA Tier 1 (beachfront) zones.
Fastener spacing: Metal panels must be fastened at intervals specified by the manufacturer's engineering data and the applicable building code. Standing seam clips are typically spaced 12-24" on center. Exposed fastener panels require screws every 12" at panel overlap seams.
Underlayment: Minimum 30# felt or synthetic underlayment. TWIA zones often require peel-and-stick self-adhering membrane at eaves, valleys, and penetrations.
Standing seam metal roofing is the top-performing roofing system for windstorm resistance. Mechanical-lock standing seam is rated for 180+ mph — far exceeding TDI minimums. Even snap-lock standing seam typically meets 140-160 mph ratings.
RISE Roofing handles the entire TDI certification process — from pre-installation engineering review to post-installation WPI-8 filing. Call (832) 345-9527 for details.
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