The Simpson HDUE 17-3/8 in. Hot-Dip Galvanized Predeflected Holdown with Strong-Drive SDS Screws by Simpson is a heavy-duty connector engineered to deliver exceptional overturning resistance in shearwall, braced wall panel, and other lateral-force-resisting applications in wood construction. Built from 12-gauge steel with a hot-dip galvanized finish, this holdown combines a predeflected seat, an overlapping back plate, and an optimized angled fastening system to provide superior strength, reduced deflection, and reliable corrosion resistance in exterior and treated-wood environments.

Key Features

• Predeflected seat - reduces deflection under load, helping maintain connection integrity during lateral force events so structures stay tighter and more stable over time.
• Angled fastening design - engages screws in tension rather than shear for higher load capacity, meaning fewer screws are required to achieve a strong, code-compliant connection.
• Angled fastening tabs and offset holes on the second back plate - guide each fastener to drive at a 45 deg. angle and prevent straight driving, ensuring every screw is positioned for maximum holding power.
• Overlapping back plate - increases fastener strength and shear values while helping prevent post splitting, adding a critical layer of structural reinforcement at the connection point.
• Optimized screw patterns - reduce splitting at the end of the post and maximize individual fastener capacity, protecting the wood member and improving overall load transfer.
• Extruded seat - adds a greater cross-sectional steel section for added strength, giving the holdown enhanced load-bearing performance at the bearing point.
• Teardrop holes - allow higher and more even distribution of load across the connector, reducing stress concentrations for a more reliable connection.
• Hot-dip galvanized 12-gauge steel construction - provides extra corrosion resistance well-suited for exterior installations and contact with treated wood, extending the service life of the connection in demanding conditions.

Why This Product

• Faster installation with included hardware - the holdown ships with 16 Strong-Drive SDS Heavy-Duty Connector screws and a crescent washer, so installers arrive on site ready to work without sourcing separate fasteners.
• Engineered to limit movement where it counts - the combination of a predeflected seat and angled fastening system actively reduces deflection under load, a meaningful advantage in shearwall and braced wall panel applications where tight tolerances matter.
• Built-in splitting protection for wood posts - the overlapping back plate, angled fastening geometry, and optimized screw layout work together to minimize the risk of post splitting, helping protect the structural member as well as the connection itself.
• Hot-dip galvanized finish for long-term durability - the HDG coating delivers a higher level of corrosion resistance than standard galvanization, making this holdown a dependable choice for exterior framing and treated-lumber applications where moisture exposure is a factor.

Specifications

• Model Number: HDUE9-SDS3.5HDG
• Gauge: 12
• Height: 17-3/8 in.
• Width: 3 in.
• Coating/Finish: Hot-Dip Galvanized
• Seat Depth: 4-5/16 in.
• Centerline: 1-7/16 in.
• Screw Offset: 1-1/2 in.
• Country of Origin: United States
• Installation Hardware: Install with 7/8 in. anchor bolt and (16) 1/4 in. x 3-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws (included)

Approved Applications

• Shearwall connections in wood construction
• Braced wall panel tie-down applications
• Lateral-force-resisting applications in residential wood structures
• Exterior and treated-wood applications requiring enhanced corrosion resistance

What's Included

Each pack contains (1) HDUE9-SDS3.5HDG Hot-Dip Galv. Predeflected Holdown, (16) 1/4 in. x 3-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and (1) crescent washer.

Frequently Asked Questions

What is the purpose of the predeflected seat on the HDUE9-SDS3.5HDG?

The predeflected seat is specifically designed to reduce deflection under load, helping maintain the structural integrity of the holdown connection during lateral force events and improving overall performance in shearwall and braced wall panel applications.

Why does the HDUE9-SDS3.5HDG use angled fastening rather than straight fastening?

The angled fastening design engages the screws in tension rather than shear, which delivers a higher load capacity while actually reducing the total number of screws required. The angled fastening tabs help drive each fastener at a 45 deg. angle, and the offset holes on the second back plate prevent the fastener from being inadvertently driven straight, ensuring every screw is installed correctly.

Is the HDUE9-SDS3.5HDG suitable for use with treated lumber or exterior applications?

Yes. The HDUE9-SDS3.5HDG is made from 12-gauge steel with a hot-dip galvanized (HDG) coating, which offers extra corrosion resistance specifically suited for exterior applications and use with treated wood.

What fasteners and hardware are needed to install the HDUE9-SDS3.5HDG?

Installation requires a 7/8 in. anchor bolt (not included) and (16) 1/4 in. x 3-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws, which are included with the holdown along with a crescent washer.

Note: Product dimensions and/or screw or bolt holes may differ from picture.