The Simpson HDU11-SDS2.5HDG 22-1/4 in. Predeflected Holdown Hot-Dip Galvanized with Strong-Drive SDS Screws is an engineered structural connector from Simpson designed for shearwall, braced-wall panel, and lateral load applications in wood-frame construction. The predeflected body virtually eliminates deflection under load due to material stretch, giving builders confidence in long-term structural performance. Combined with hot-dip galvanized coating for enhanced corrosion resistance and included SDS screws for a streamlined installation, this holdown is built to perform in demanding interior and exterior environments alike.

Key Features

• Predeflected body - virtually eliminates deflection due to material stretch under load, so the connector holds its position reliably over the life of the structure without the gradual shift common in standard holdowns
• Strong-Drive SDS Heavy-Duty Connector screws included - screws install easily and reduce fastener slip, getting the job done faster and with greater consistency than traditional bolt-based fastening
• SDS screws provide a greater net section area of the post compared to bolts - less material is removed from the post during installation, preserving the structural capacity of the framing member
• No stud bolts to countersink at openings - simplifies the installation process and eliminates a time-consuming step, particularly at window and door openings
• Made from 10-gauge steel - heavy-gauge construction delivers the rigidity and load resistance required for demanding lateral force applications
• Hot-dip galvanized (HDG) coating - provides extra corrosion resistance beyond standard finishes, making this holdown well suited for exterior installations and applications involving treated wood where moisture exposure is a concern

Why This Product

• Engineered to minimize movement under load - the predeflected manufacturing process addresses one of the most common failure points in holdown performance: material stretch. Builders get a connector that behaves predictably once the structure is placed under lateral stress.
• Fasteners are included and matched to the connector - the 30 included 1/4 in. x 2-1/2 in. Strong-Drive SDS screws and crescent washer are selected specifically for this holdown, eliminating guesswork and ensuring proper fastener pairing right out of the package.
• Hot-dip galvanized for tough environments - where standard zinc-plated connectors fall short, the HDG finish holds up in exterior conditions and alongside pressure-treated lumber, reducing the risk of corrosion-related connection failure over time.
• Screws outperform bolts in key installation and structural metrics - reduced fastener slip, easier driving, and a greater net section area of the post make the SDS screw connection a practical and structural improvement over conventional bolt-based holdown designs.

Specifications

• MPN: HDU11-SDS2.5HDG
• Height: 22-1/4 in.
• Gauge: 10
• Coating: Hot-Dip Galvanized
• Finish: Hot-Dip Galvanized
• Install With: Install with 1 in. anchor bolt and 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws (included)
• Country of Origin: United States

What's Included

Each pack contains (1) HDU11-SDS2.5HDG Predeflected Holdown, (30) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer.

Downloads and Resources

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Frequently Asked Questions

What does "predeflected" mean and why does it matter?

The HDU11-SDS2.5HDG holdown body is pre-deflected during the manufacturing process, which virtually eliminates deflection under load due to material stretch. This means the connector maintains its structural integrity and holds its position more reliably once installed and placed under load, compared to standard holdowns that can shift or deform over time.

Why are SDS screws used instead of bolts?

The 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws install easily, reduce fastener slip, and provide a greater net section area of the post compared to bolts. There are also no stud bolts to countersink at openings, simplifying the installation process.

Is this holdown suitable for exterior or treated-wood applications?

Yes. The hot-dip galvanized (HDG) coating offers extra corrosion resistance, making the HDU11-SDS2.5HDG well suited for exterior and treated-wood applications where exposure to moisture or corrosive conditions is a concern.

Do the required fasteners come with this holdown?

Yes. The HDU11-SDS2.5HDG includes (30) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer, ensuring that the proper fasteners are used for a correct and code-compliant installation. A 1 in. anchor bolt is also required for installation.

Note: Product dimensions and/or screw or bolt holes may differ from picture. Please see item description for specifications.