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What is the difference between TDI and TWIA?

The process of obtaining certification of a new home or alteration can be confusing for homeowners and even contractors. Wading through these waters is necessary, however, to obtain a windstorm and hail insurance policy through TWIA or your insurance company.

Will you need a certificate from TDI or TWIA?  What’s the difference between a WPI-8 and a WPI-8E?

These are great questions. First, let’s define the organizations and then we’ll get in to the different certifications needed to properly insure your investment.

TDI (Texas Department of Insurance) regulates the state’s insurance industry, oversees the administration of the Texas workers’ compensation system, performs the duties of the State Fire Marshal’s Office, and provides administrative support to the Office of Injured Employee Counsel – a separate agency (

TWIA (Texas Windstorm Insurance Agency) is a residual market property insurance company and is not a state agency. TWIA is one of 36 residual market property insurers in the United States. These residual markets are created by state law to provide consumers with another alternative for insurance when coverage is unavailable through traditional private sector insurance carriers. When the private sector determines the risk of loss is too great and is unwilling to write coverage voluntarily, applicants can seek coverage through the residual market mechanism (

Now, about the certifications.

TDI is the only entity that is capable of issuing certificates of compliance (WPI-8 or WPI-8E) for completed improvements. These certificates are used by TWIA and other insurance companies to verify that the structure’s design and construction conformed to the applicable building code. The only individuals allowed to declare that a structure conformed to the building code for TDI certificate of compliance are professional engineers listed on the TDI appointed qualified inspectors list and TDI inspectors.

What’s the difference between the WPI-8 and WPI-8E?

A WPI-8 is issued from TDI and is used for new and ongoing construction projects. For example, if you are starting the process of designing your new home or contemplating a remodel and you contact our office prior to project completion, you will receive a WPI-8 if all design and construction is in compliance with applicable building codes.

A WPI-8E is issued by TDI and is used for projects that have completed construction. For example, you purchased a home and found that the roof replaced in 2008 never was inspected or certified, and you want to ensure this new roof can have wind and hail coverage, you will receive a WPI-8E certificate.

Verifying completed construction meets the applicable building code can be destructive and costly, and the process for obtaining certificates for completed construction are much more difficult than new or ongoing projects. It is highly recommended that you call Lynn Engineering prior to starting any construction.

We understand construction in wood, steel and concrete – and we are experts in design for coastal construction. Visit us online at or call (979) 245-8900 to speak with our professionals or schedule an inspection today.

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