The Simpson HDQ8-SDS3HDG 14 in. Hot-Dip Galvanized Holdown is a heavy-duty structural connector from Simpson built to anchor wood framing securely in high-load applications such as shear wall assemblies and seismic or wind-resistant construction. The unique seat design of the HDQ8 greatly minimizes deflection under load, and the holdown may be installed either flush or raised off the mudsill without a reduction in load value - giving contractors meaningful flexibility on the jobsite. Strong-Drive SDS Heavy-Duty Connector screws are included, delivering a faster, cleaner installation compared to traditional bolt-and-countersink methods.

Key Features

• Included SDS screws matched to the holdown - eliminates guesswork about fastener compatibility and ensures the correct hardware is always on hand at installation
• No stud bolts to countersink at openings - simplifies installation at rough openings and reduces labor time in the field
• Strong-Drive SDS Heavy-Duty Connector screws - reduce fastener slip and provide a greater net section when compared to bolts, supporting stronger, more reliable connections
• Flush or raised mudsill installation - load value is maintained in either position, giving framers the flexibility to adapt to site conditions without compromising performance
• 7-gauge steel construction - provides the material thickness needed to handle demanding structural loads in residential and light commercial framing
• Hot-dip galvanized finish - delivers extra corrosion resistance suited to exterior installations and contact with treated lumber, where standard coatings may break down prematurely

Why This Product

• Engineered to fight deflection - the unique seat design of the HDQ8 specifically targets deflection under load, helping maintain structural integrity in high-stress shear wall and tie-down applications
• Screw-based fastening speeds up the install - replacing traditional bolt methods with Strong-Drive SDS screws means no countersinking, less setup time, and reduced fastener slip throughout the life of the connection
• Built for demanding environments - hot-dip galvanization goes beyond standard coatings to protect against corrosion in exterior conditions and treated-wood framing where moisture and chemical exposure are ongoing concerns
• Installation flexibility without penalty - the ability to mount flush or raised off the mudsill without losing load capacity gives crews room to work around field conditions while staying within engineered performance requirements

Specifications

• Model Number: HDQ8-SDS3HDG
• Height: 14 in.
• Gauge: 7-gauge steel
• Coating: Hot-Dip Galvanized
• Finish: Hot-Dip Galvanized
• Install With: 7/8 in. anchor bolt and 1/4 in. x 3 in. Strong-Drive SDS Heavy-Duty Connector screws (included)
• Width: 2-7/8 in.
• Seat Depth: 2-1/2 in.
• Centerline: 1-1/4 in.
• Screw Offset: 2-3/8 in.
• Country of Origin: United States

What's Included

Each pack contains (1) HDQ8-SDS3HDG Holdown, 1/4 in. x 3 in. Strong-Drive SDS Heavy-Duty Connector screws.

Downloads and Resources

• View Specifications

Frequently Asked Questions

Why does the HDQ8-SDS3HDG use SDS screws instead of bolts?

The Strong-Drive SDS Heavy-Duty Connector screws install easily, reduce fastener slip, and provide a greater net section when compared to bolts. They are supplied with the holdown to ensure that the proper fasteners are always used.

Can the HDQ8-SDS3HDG be installed raised off the mudsill?

Yes. The HDQ8-SDS3HDG may be installed either flush or raised off the mudsill without a reduction in load value, offering added flexibility during installation.

What makes the HDQ8-SDS3HDG suitable for exterior and treated-wood applications?

The hot-dip galvanization (HDG) finish provides extra corrosion resistance, making this holdown well suited for exterior and treated-wood applications where standard coatings may be insufficient.

What anchor bolt is required to install the HDQ8-SDS3HDG?

The HDQ8-SDS3HDG installs with a 7/8 in. anchor bolt along with the included 1/4 in. x 3 in. Strong-Drive SDS Heavy-Duty Connector screws.