Description

Key Features

Predeflected Design

The body is predeflected during manufacturing to virtually eliminate deflection from material stretch. That helps the holdown do its job without the extra movement that can show up under load.

Correct Screws Included

This Simpson Strong-Tie holdown ships with the required Strong-Drive SDS heavy-duty connector screws and a crescent washer. You are not guessing on fasteners or chasing down the right hardware before installation.

Built for Shearwalls

Designed for shearwalls, braced-wall panels, and other lateral load applications, the HDU11-SDS2.5 is made for structural connections where uplift resistance matters. It is a practical choice for high-wind construction and other demanding framing work.

Overview

The Simpson Strong-Tie HDU11-SDS2.5 HDU 22-1/4 in. Galvanized Predeflected Holdown with Strong-Drive SDS Screws is a structural holdown for wood construction. This is a holdown designed for shearwall, braced-wall panel, and other lateral load applications. Model Number: HDU11-SDS2.5. If you are tying framing to the foundation to resist uplift and overturning forces, this is the kind of connector you use when a basic bracket is not enough.

What makes this one matter is the predeflected body. Simpson Strong-Tie forms the holdown so it virtually eliminates deflection under load caused by material stretch. In real terms, that means the connection tightens up faster and behaves more like you expect when the wall starts taking load. On structural connectors, less movement is the whole point.

The HDU11-SDS2.5 uses Strong-Drive SDS heavy-duty connector screws instead of making you deal with a pile of field-selected bolts through the post. That saves installation time, reduces fastener slip, and gives greater net section area of the post compared to bolts. It also avoids stud bolts that need to be countersunk at openings, which is one of those details that sounds small until you are actually laying out framing and trying to keep things moving.

This holdown is made from 10-gauge steel with a zinc galvanized G90 finish. For this specific model, the body measures 3 inches wide, 22-1/4 inches high, and 3-1/2 inches at the base dimension listed by Simpson Strong-Tie. That longer body and heavier gauge put it in the category for bigger load-path connections, not light trim or general-purpose framing hardware.

Installation is straightforward when you use the hardware it was designed around. Simpson Strong-Tie notes that the HDU requires no additional washer, and the supplied SDS connector screws are intended to be installed with a low-speed, high-torque drill using a 3/8 inch hex-head driver. The package includes (30) 1/4 inch x 2-1/2 inch Strong-Drive SDS heavy-duty connector screws and (1) crescent washer, so the main connector hardware is already matched to the holdown.

From a jobsite practicality standpoint, the included fasteners are a big deal. Structural connectors only perform as intended when the correct fasteners are used. Simpson Strong-Tie takes that variable out of the equation here by packaging the holdown with the proper SDS screws. That helps with consistency across the crew and reduces the chance of someone grabbing the wrong screw bucket because it was closer.

The galvanized finish also makes sense for typical wood framing exposure conditions where corrosion resistance is required beyond bare steel. Simpson Strong-Tie lists this model with a zinc galvanized G90 coating, while the HDU family is also available in hot-dip galvanized versions for tougher exposure requirements. For buyers comparing options, that means you should match this exact HDU11-SDS2.5 finish to the environment and the treatment level of the lumber being used.

This Simpson Strong-Tie holdown is best for framers, builders, structural carpenters, engineers specifying wood shearwall connections, and serious remodelers working on reinforcement or retrofit details. If your project calls for a structural holdown with supplied screws, minimal installation guesswork, and a design meant to control deflection under load, this is a smart pick. If you are just looking for general framing hardware, this is more connector than you need.

See the Load Path Clearly

This is where a holdown earns its keep. The HDU design ties the wood member back to the foundation to resist uplift and overturning forces in shearwall and braced-wall panel construction.

• Designed for shearwalls, braced-wall panels, and other lateral applications
• Used in high-wind construction where a stronger load path matters

Faster Installation, Less Guesswork

The included SDS connector screws are part of the appeal here. Instead of piecing together hardware in the field, you get the fasteners Simpson Strong-Tie specifies for the connector.

• Includes (30) 1/4 in. x 2-1/2 in. Strong-Drive SDS heavy-duty connector screws
• Includes (1) crescent washer and requires no additional washer

Designed to Reduce Deflection

The formed body is not just for looks. The predeflected design helps the connector take load with less movement from material stretch, which is exactly what you want in a structural connection.

• Predeflected body virtually eliminates deflection due to material stretch
• Uses screws that reduce fastener slip compared to bolt-based setups

Built from Heavy Structural Steel

This is not light-duty hardware. The HDU11-SDS2.5 uses 10-gauge steel and a zinc galvanized G90 finish for structural framing applications where strength and corrosion resistance both matter.

• 10-gauge steel construction
• Zinc galvanized G90 finish for corrosion resistance

What’s in the Box

• (1) Simpson Strong-Tie HDU11-SDS2.5 holdown
• (30) 1/4 in. x 2-1/2 in. Strong-Drive SDS Heavy-Duty Connector screws
• (1) crescent washer

Key Specifications

Type	Holdown
Model	HDU11-SDS2.5
Material	Steel
Gauge	10 ga.
Finish	Zinc Galvanized, G90
Height	22-1/4 in.
Width	3 in.
Base Dimension	3-1/2 in.
Centerline Dimension	1-3/8 in.
Seat Offset	1-1/2 in.
Weight	6.7 lbs
Package Quantity	1

Compatibility

Fastener System

Designed to use Strong-Drive SDS heavy-duty connector screws. This model includes the required screws for installation.

Driver Requirement

Simpson Strong-Tie specifies best installation with a low-speed, high-torque drill and a 3/8 in. hex-head driver.

Materials Connected

Intended for wood-to-wood structural connections in framed wall and post applications.

Built For

Construction Carpentry General Contracting Remodeling Shearwall Construction Braced-Wall Panels High-Wind Construction Structural Wood Framing

Pro Tip

Use a low-speed, high-torque drill with a 3/8 inch hex-head driver when running the included SDS screws. These screws install cleaner and with better control that way than trying to hammer them in with a fast drill set too aggressively.

At a Glance

22-1/4 in.

Height

10 ga.

Steel Gauge

30

Included SDS Screws

G90

Galvanized Finish

Tool Nut’s Take

Tool Nut’s Take

Simpson Strong-Tie HDU11-SDS2.5 Holdown That Cuts Down Installation Headaches

The big win here is getting a serious structural holdown with the correct SDS screws in the box and a predeflected design that helps control movement under load.

• Who it’s for: Framers, builders, and remodelers working on shearwalls, braced-wall panels, and other structural wood connections where uplift resistance is part of the plan.
• Why it stands out: The predeflected body, included Strong-Drive SDS screws, and no-extra-washer setup make this faster and cleaner to install than holdown systems that leave too much up to the field.
• Worth knowing: This is structural hardware, not a generic bracket. Match the finish and installation details to the job requirements, especially when treated lumber or harsher exposure conditions are involved.

Common Questions

• What is this holdown used for? It is designed for use in shearwalls, braced-wall panels, and other lateral applications in wood construction.
• Does the HDU11-SDS2.5 use bolts through the post? It uses Strong-Drive SDS heavy-duty connector screws, which help reduce fastener slip and provide greater net section area of the post compared to bolts.
• What finish does this model have? This specific HDU11-SDS2.5 model uses a zinc galvanized G90 finish.
• What drill setup does Simpson Strong-Tie recommend? Simpson Strong-Tie says the SDS connector screws install best with a low-speed, high-torque drill equipped with a 3/8 inch hex-head driver.