The Simpson HDUE9-SDS3.5 Galvanized Predeflected Holdown from Simpson is a 12-gauge structural connector engineered to deliver exceptional overturning resistance in wood-framed construction. Designed for shearwall holdown connections, braced wall panel anchorage, and lateral-force-resisting applications, this holdown combines a predeflected seat, an overlapping back plate, and angled fastening geometry to reduce deflection, prevent post splitting, and maximize load capacity - making it a dependable choice for modern residential structural systems.

Key Features

• Predeflected seat reduces deflection under load - keeps the holdown connection tighter and more stable during lateral force events, protecting overall structural performance
• Angled fastening engages the screws in tension for higher load capacity - reduces the total number of screws required while delivering superior holding strength compared to straight fastener installation
• Angled fastening tabs help drive the fastener at a 45 deg. angle, and offset holes on the second back plate block the fastener from being driven straight - ensures every screw is installed correctly for consistent, code-reliable performance on every job
• Overlapping back plate increases fastener strength and shear values, helping prevent post splitting - protects the integrity of the structural post and reduces callbacks caused by fastener-related wood damage
• Optimized screw patterns reduce splitting at the end of the post and maximize individual fastener capacity - means fewer fasteners carry more load, and the post stays intact even under demanding lateral forces
• Extruded seat adds a greater cross-sectional steel section for added strength - provides a more robust bearing surface that supports higher allowable loads at the base of the connection
• Teardrop holes allow higher and more even distribution of load - reduces stress concentrations across the connector, contributing to longer service life under cyclic loading
• Made from 12-gauge steel with a G90 zinc galvanized finish - provides reliable corrosion resistance suitable for treated-lumber framing environments

Why This Product

• Faster installation with included hardware - each holdown ships with (16) 1/4 in. x 3-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws and a crescent washer, so installers have everything needed to complete the connection without sourcing separate fasteners
• Engineered to reduce job-site errors - the angled fastening tabs physically guide screws to the correct 45 deg. angle, and the offset holes prevent straight installation, making it difficult to fasten the holdown incorrectly even under fast-paced framing conditions
• Multi-mechanism approach to splitting prevention - the overlapping back plate and optimized screw patterns work together to protect the post from end splitting, reducing structural rework and material waste on the job site
• Purpose-built for lateral-force-resisting applications - the combination of a predeflected seat, extruded base, and teardrop holes addresses the specific demands of shearwall and braced wall panel anchorage in residential wood construction, delivering reliable performance where it matters most

Specifications

• Model No.: HDUE9-SDS3.5
• Height: 17-3/8 in.
• Width: 3 in.
• Gauge: 12
• Coating/Finish: Zinc Galvanized, G90
• Seat Depth: 4-5/16 in.
• Centerline: 1-7/16 in.
• Screw Offset: 1-1/2 in.
• Country of Origin: United States
• Installation: 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 holdown connections in wood construction
• Braced wall panel anchorage
• Lateral-force-resisting applications in residential wood structures

What's Included

Each pack contains (1) HDUE9-SDS3.5 Galvanized 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-SDS3.5?

The predeflected seat is specifically engineered to reduce deflection under load, which helps maintain the structural integrity and performance of the holdown connection during lateral force events.

Why does this holdown use angled fastening instead of straight fastener installation?

The angled fastening tabs help drive the fastener at a 45 deg. angle, which engages the screws in tension for higher load capacity. This approach reduces the total number of screws required while delivering superior performance compared to straight fastener installation.

What type of fasteners are used to install the HDUE9-SDS3.5, and are they included?

The holdown installs with 1/4 in. x 3-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws along with a 7/8 in. anchor bolt. The (16) SDS screws and (1) crescent washer are included with the holdown.

What material and corrosion protection does the HDUE9-SDS3.5 feature?

The HDUE9-SDS3.5 is made from 12-gauge steel and features a G90 zinc galvanized coating, providing strong corrosion resistance suitable for residential construction applications.

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