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HTT Tension Tie & Holdown

Simpson Strong‑Tie offer a wide variety of holdown devices designed and tested to address many applications and load demands. The HTT Tension Tie & Holdown is designed for heavy‑duty holdown applications on single or double studs and offer a solution for resisting tension loads.

The heavy‑duty HTT is ideal for retrofit or new construction projects. They provide high-strength, post-pour, concrete-to-steel connections. The HTT is also suitable for residential and commercial projects, sub diaphragm floor, seismic upgrades, mid floor vertical connection applications.

The HTT is a single-piece formed tension tie — no rivets, no welding points and a 4-ply formed seat. No washers are required. They feature an optimised nailing pattern which results in better performance with less deflection.

Key Features
  • A single piece folded and no weak point of welding, provide ultimate strength tension tile
  • Unique nailing patten that provides better results with less deflection
  • Stronger and safer than typical through-bolt installations for deck post connections
  • Uses Strong-Drive® SDS Heavy-Duty Connector screws which install easily, reduce fastener slip and provide a greater net section area of the post compared to bolts
  • Suitable for heavy duty holdown applications on single or double studs
  • Helps prevent a common type of deck failure
  • 15mm diameter anchor hole can accommodate Simpson Strong-Tie M12 Titen HD Screw Anchor or any M14 threaded rods
  • HTT5 and HTT5KT are suitable for steel frame holdown connections
Scope of Use


  • Heavy‑duty holdown applications
  • Resisting tension load applications 
  • Shearwalls, studs to foundation connections
  • Concrete-to-steel connections
  • Retrofit or new construction projects
  • Residential and commercial projects
  • Sub diaphragm floor, seismic upgrades, mid floor vertical connection applications
  • Steel frame applications
Limitations on Use


  • Use all specified fasteners
  • The HTT requires no additional washer
  • Strong‑Drive SDS Heavy‑Duty Connector screws install best with a low speed high torque drill with a 3/8” hex head driver
Statement of Building Code Compliance
  • HTT Tension Tie & Holdowns are compliant with NZS 3604:2011
B1 Structure compliant
B2 Durability compliant
Independent Assessment
Independent Assessment
Test Results
Test Results
CAD Drawings
Technical Data Sheet
IAPMO UES Evaluation Report


Product Approval


Research Report


Research Report


Installation Guide
Full Catalogue: Timber Connectors NZS3604


A leader in structural systems research, testing and innovation, Simpson Strong-Tie is among the world's largest suppliers of solutions and products, helping build safer, stronger structures.

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