The Simpson THAI422 Adjustable I-Joist Truss Hanger is a top-flange connector engineered by Simpson for 3-1/2 in. I-joists, 4x10, 4x12, and 4x truss members. Its extra-long straps can be field-formed directly on the jobsite, giving installers the height adjustability needed to achieve a precise, code-compliant connection across a range of engineered wood and dimensional lumber applications. Built from 18-gauge steel with a G90 zinc galvanized finish, this hanger delivers durable, corrosion-resistant support underneath the joist at the header connection point.

Key Features

• Positive-angle nailing (PAN) - drives fasteners at the optimal angle to help eliminate splitting of the I-joist's bottom flange, protecting the integrity of engineered wood members during and after installation
• Field-formable extra-long straps - can be bent over the top of the header on the jobsite, providing height adjustability without special tools or pre-ordered custom parts
• Top-flange hanger design - sits over the header for a clean, concealed bearing that supports the joist from beneath while keeping the installation flush and structurally sound
• 18-gauge steel construction - provides the structural strength required for demanding framing connections across I-joists, dimensional lumber, and truss members
• G90 zinc galvanized finish - delivers enhanced corrosion resistance, making this hanger suitable for moisture-exposed framing environments where long-term durability matters

Why This Product

• Built-in height adjustability for real jobsite conditions - the field-formable strap design accommodates joist depths from 9-1/4 in. to 14 in., letting framers dial in the correct seat height on-site rather than working around fixed hanger sizes
• Protects engineered wood from installation damage - positive-angle nailing (PAN) reduces the risk of bottom-flange splitting, a critical concern when fastening into I-joists where flange damage can compromise load performance
• Versatile compatibility across multiple member types - a single hanger model handles 3-1/2 in. I-joists, 4x10, 4x12, and 4x truss members, reducing the number of SKUs a framer needs to stock for a project
• Corrosion-resistant finish for lasting structural connections - the G90 zinc galvanized coating helps the hanger resist deterioration over time, supporting reliable long-term performance in framed floor and roof assemblies

Specifications

• MPN: THAI422
• Brand: Simpson Strong-Tie
• Gauge: 18
• Coating / Finish: Zinc Galvanized, G90
• Joist Width: 3-1/2 in.
• Joist Depth: 9-1/4 in. to 14 in.
• Seat Width: 3-9/16 in.
• Compatible Member Size: 3-1/2 I-joist, 4x10, 4x12, 4x truss
• Install With: (6-20) 0.148 in. x 3 in. nails in the header and (2) 0.148 in. x 1-1/2 in. nails in the joist
• Country of Origin: United States

Approved Applications

• 3-1/2 in. engineered wood I-joists requiring adjustable top-flange hanger connections
• 4x10 and 4x12 dimensional lumber joist-to-header connections
• 4x truss-to-header connections
• Applications where joist depth ranges from 9-1/4 in. to 14 in. and field height adjustment is required

Options

• Contact us for Configurable Options and Special orders

Frequently Asked Questions

What joist sizes is the THAI422 compatible with?

The THAI422 is designed for members with a joist width of 3-1/2 in. and a joist depth ranging from 9-1/4 in. to 14 in. Compatible member types include 3-1/2 in. I-joists, 4x10, 4x12, and 4x truss.

What fasteners are required to install the THAI422?

Installation requires (6-20) 0.148 in. x 3 in. nails in the header and (2) 0.148 in. x 1-1/2 in. nails in the joist. Always use all specified fasteners and verify that the header can accommodate the specified nailing pattern.

How does the THAI422 achieve height adjustability in the field?

The THAI422 features extra-long straps that can be field-formed over the top of the header, providing height adjustability and top-flange hanger convenience without requiring factory pre-configuration for every joist depth within the 9-1/4 in. to 14 in. range.

Why is positive-angle nailing (PAN) important for I-joist hangers?

Positive-angle nailing (PAN) drives nails at an angle that directs force away from the I-joist's bottom flange, helping to eliminate splitting of that flange during installation - a critical consideration for maintaining the structural integrity of engineered wood I-joists.

Note: Product dimensions may differ from picture.