The Simpson Strong-Tie HDU5-SDS2.5 is a pre-deflected holdown designed for structural applications where load stability and ease of installation are critical. This guide provides a comprehensive overview of the product's features, specifications, and installation procedures, based on the manufacturer's documentation and supporting technical data. The HDU5-SDS2.5 is intended for use in wood construction and is supplied with Strong-Drive SDS Heavy-Duty Connector screws, eliminating the need for additional fasteners or washers in most cases.
Product Overview
The HDU5-SDS2.5 is part of Simpson Strong-Tie’s line of pre-deflected holdowns, engineered to minimize deflection under load due to material stretch. This design feature ensures that the holdown remains stable and secure, even under significant stress. The product is available in a hot-dip galvanized finish (HDU5-SDS2.5HDG) and is compatible with a range of structural wood post applications.
One of the key design elements of the HDU5-SDS2.5 is the inclusion of teardrop-shaped holes, which allow for greater and more even distribution of load. This not only enhances structural integrity but also simplifies alignment during installation. The holdown is designed to be used with Strong-Drive SDS Heavy-Duty Connector screws, which are included with the product and are optimized for low-slip installation and high-strength performance.
Key Features
The HDU5-SDS2.5 offers several features that make it a preferred choice for structural wood connections:
Pre-Deflected Design: The holdown is pre-deflected to reduce movement and deflection caused by material stretch when under load. This eliminates the need for post-installation adjustments, ensuring a stable connection from the start.
Strong-Drive SDS Heavy-Duty Connector Screws: These screws are supplied with the holddown and are specifically designed for this application. They offer improved torque resistance and reduce the risk of fastener slip compared to traditional bolts. The screws also allow wood posts to retain a greater net section than bolts, preserving the structural integrity of the wood.
No Countersinking Required: Unlike some fastening systems that require stud bolts to be countersunk at openings, the HDU5-SDS2.5 eliminates this step. This simplifies the installation process and reduces labor time.
No Additional Washers Needed: The holddown is designed so that no additional washer is required. This is in contrast to the DTT model, which requires a standard cut washer to be installed between the nut and the seat. The absence of additional components reduces the risk of misinstallation and ensures a cleaner connection.
Ease of Installation: The HDU5-SDS2.5 is designed for fast and efficient installation. The use of pre-supplied Strong-Drive SDS screws and the absence of required washers or countersinking steps streamline the process.
Compatibility with ICC-ES AC155 Standards: The HDUE series, which includes the HDU5-SDS2.5, is tested and certified in accordance with ICC-ES AC155 standards. These standards ensure that the holdowns meet the required performance criteria for structural applications.
Product Specifications
| Specification | Value |
|---|---|
| Brand | Simpson Strong-Tie |
| Model | HDU5-SDS2.5 |
| Finish | Hot-Dip Galvanized (G90 Galvanized) |
| Length | 13-3/16 inches |
| Fastener Type | Strong-Drive SDS Heavy-Duty Connector Screws |
| Installation Method | Pre-deflected, no countersinking required |
| Compatibility | Structural wood post applications |
These specifications indicate that the HDU5-SDS2.5 is a robust and durable holdown, suitable for a variety of wood construction applications. The hot-dip galvanized finish provides corrosion resistance, making it suitable for both indoor and outdoor use in moderate environmental conditions.
Installation Instructions
Tools and Equipment
To install the HDU5-SDS2.5 holdown, the following tools and equipment are recommended:
Low-Speed, High-Torque Drill: A 3/8" hex head driver is recommended for optimal screw installation. This type of drill provides the necessary torque without damaging the screw threads or the wood.
Simpson Strong-Drive SDS Heavy-Duty Connector Screws: These are included with the holdown and should be used as specified.
Measuring Tape and Pencil: For accurate placement and alignment of the holdown.
Hammer (if needed): In some cases, a hammer may be used to gently seat the holdown into the structure.
Step-by-Step Installation Process
Positioning the Holdown:
- Determine the location for the holdown based on the structural design and engineering requirements. Ensure that the holdown is aligned with the wood post and the supporting structure.
- Mark the position on the wood post using a measuring tape and pencil.
Aligning the Holdown:
- Place the HDU5-SDS2.5 holdown at the marked position. The teardrop-shaped holes should align with the pre-drilled or cut openings in the wood post and the supporting structure.
- Check that the holdown is level and properly seated. Adjust as necessary to ensure a secure fit.
Installing the Screws:
- Insert the included Strong-Drive SDS Heavy-Duty Connector screws into the designated holes.
- Use a low-speed, high-torque drill with a 3/8" hex head driver to tighten the screws. Ensure that the screws are fully seated and that the holdown is securely fastened to both the wood post and the supporting structure.
Verification and Adjustment:
- After installation, verify that the holdown is secure and that there is no movement or misalignment.
- If adjustments are needed, carefully remove the screws and realign the holdown before re-installing the screws. Avoid over-tightening the screws to prevent damage to the wood or the holdown.
Final Inspection:
- Inspect the installation for any signs of misalignment, damage, or improper fastening.
- Ensure that all specified fasteners have been used and that the installation meets the manufacturer’s guidelines.
Additional Notes
No Additional Washers Required: The HDU5-SDS2.5 does not require additional washers. This simplifies the installation process and reduces the risk of misinstallation. However, if the holdown is being installed alongside other components that require washers (e.g., DTT2Z), ensure that the appropriate washers are included.
Use All Specified Fasteners: It is important to use all of the specified fasteners during installation. Omitting any fasteners may compromise the structural integrity of the connection.
Follow Manufacturer Guidelines: Always refer to the manufacturer’s installation instructions and technical specifications when working with structural components. These guidelines are designed to ensure the safety and effectiveness of the installation.
Compatibility and Applications
The HDU5-SDS2.5 is specifically designed for use in wood construction applications where a secure, pre-deflected connection is required. It is commonly used in the following scenarios:
- Residential Construction: For securing wood posts to foundation walls, floor joists, or other structural supports.
- Commercial Construction: In larger-scale projects where multiple holdowns are needed for load-bearing structures.
- Repair and Retrofit Projects: For reinforcing existing wood structures or replacing damaged or outdated connections.
The product is compatible with a range of wood post sizes and types, making it a versatile option for various construction needs. It is also compatible with ICC-ES AC155 standards, ensuring that it meets the necessary performance criteria for structural applications.
Maintenance and Longevity
To ensure the longevity and effectiveness of the HDU5-SDS2.5 holdown, it is important to perform regular inspections and maintenance. This includes:
Visual Inspections: Periodically check the holdown for signs of wear, corrosion, or damage. Look for any movement or misalignment that could indicate a problem with the connection.
Fastener Check: Ensure that all screws are still properly seated and that there is no loosening or damage to the threads.
Environmental Considerations: If the holdown is installed in an outdoor environment, ensure that it is protected from excessive moisture or exposure to corrosive elements. The hot-dip galvanized finish provides corrosion resistance, but it may degrade over time in harsh conditions.
Re-tightening: In some cases, it may be necessary to re-tighten the screws to maintain the integrity of the connection. This should be done according to the manufacturer’s guidelines and using the recommended tools.
Conclusion
The Simpson Strong-Tie HDU5-SDS2.5 is a high-performance holdown designed for structural wood applications. Its pre-deflected design, inclusion of Strong-Drive SDS Heavy-Duty Connector screws, and ease of installation make it a reliable and efficient choice for both residential and commercial construction. By following the manufacturer’s installation guidelines and performing regular maintenance, users can ensure that the holddown continues to provide a secure and stable connection over time.