New Water Control Standard

GT-1 already adopted by 30+ states, counties, & cities!


*Local jurisdictions, no state-wide code.

What is ANSI/SPRI GT-1?

  • Like ANSI/SPRI/FM 4435/ES-1 is to fascia and coping, ANSI/SPRI GT-1 provides a standard test method for load resistance for gutter systems that secure membrane on commercial low slope roof systems.

  • Became a standard in 2016.

  • Adopted into the 2021 International Building Code.

  • Located in Chapter 15: Roof Assemblies and Rooftop Structures.

  • Design/wind load calculations based on ASCE 7, Minimum Design Loads and Associated Criteria for Buildings and Other Structures.

  • Three Test Methods: G-1 (Horizontal Pressure), G-2 (Vertical Pressure), and G-3 (Water/Ice/Snow Load).

  • GT-1 testing is specific to a product’s components, materials, dimensions, fasteners, and fastening patterns.


GT-1 Test Methods